Everything Car Audio

Amplifier Troubleshooting

2009-08-30T00:08:00.000-07:00

Please try these things before sending in your amplifier. By the numbers, 40% of all amps returned to us work just fine and there is a problem in the wiring or install.
You must have a DMM (Digital Muti Meter) and know how to use it.
If no: take it to someone who does.
If yes: thumb through the following scenarios

Amp will not come on (no lights):

Set DMM to DC voltage and check at the amp. You need to test with both (+ & -) leads on the amplifier Power terminals.

If over 12 volts: check both sides of the fuses in the amp.
If no or low voltage: ground the DMM (-) test lead to a good, clean, metal chassis ground in the vehicle and retest.

If over 12 volts now: problem is in the ground wire or connection (between the amplifier and its chassis ground).

If still no voltage: check both sides of the fuse by the battery.

NOTE: You cannot check a fuse by just looking. Fuses can be “bad” and not blown; especially the larger, cheap-ass, glass ones.

If blown or bad: replace and start beatin’ again!

If all is good with battery voltage, it is now time to check the remote (or turn on) wire. Check voltage at terminal of amp.

If no voltage: check voltage at head unit. You can also make a jumper from the main 12V+ connection to the remote terminal to see if the amp comes on. If it does, the problem is in the head unit remote output or remote wire between the head unit and the amplifier.

If all power wiring tests good, remove the amp from the vehicle and test with short jumper wires directly at the battery, using a jumper wire from amp 12V+ to the remote terminal, just as a “I need to make sure” final test. If it still doesn’t come on, it needs to be sent in.

Amp turns on but goes into protect:

Disconnect RCAs and speakers and try turning the amp on again.

If it still goes into protect with just power, ground and remote; the amp is bad.

If it is now on and not in protect: connect the RCA’s first.
If it goes into protect: the problem is in the cables or headunit. Change and retest.

If still not in protect: reconnect speakers
If it goes into protect: problem is in the speakers or wiring (most likely shorted [or grounded] wiring or burnt coils). Set DMM to 'ohms' and first test by shorting leads together. This number (usually in the .4 range) will be subtracted from any reading you get. Connect DMM leads to each speaker wire pair. If you have a short, reading same as touching the leads together, trace the wiring to find short.

If no short in wiring: test the speakers individually and eliminate problem.

If amp comes on (and not in protect) and has no output:

Check all settings. Turn deck on at low volume.
       Master/Slave switch in master position.
       Gain all the way up.
       Subsonic filter all the way down.
       Boost all the way down.
       X-over all the way up.

If still no sound: you will need to try an alternate input. The best is a signal generator right to the input of the amp. Alternately, you could use another radio wired in with temporary wiring right at the amp with a very short, known-working RCA cord.

If still no sound: try a known-working test speaker with very short wiring right to the amp terminals. If still no sound: amp is bad. This is a very rare failure but it can happen.

Amp has distorted output:

Same test as above. You need to eliminate all the variables.

If you are testing a stereo amp and you have the problem on one channel:

Swap RCA’s: if it changes sides, the problem is in the deck or RCA cables.

If same side: swap speaker outputs at the amp. If it changes sides, the problem is in the amp. If it stays on the same side, the problem is in the wiring or speaker.

Amp plays but has low output:

Check all settings. Turn deck on at low volume.
       Master/Slave switch in master position.
       Gain all the way up.
       Subsonic filter all the way down.
       Boost all the way down.
       X-over all the way up.

Turn up the radio. If problem remains:

Check voltage drop at amp power input terminals. Set your meter to DC voltage with the hold feature activated. If your meter does not have that feature you will need to watch it to see how low the voltage drops when it is trying to play loud. If voltage drops below 11 volts at any time, you need more battery/alternator power and or better wiring.

If voltage remains above 12 the entire time, you need to check the speakers.

Set meter to ohms and check the DC resistance of the speaker load. If it falls within the proper load for the amp, check the amp, hooked to known-working speakers. If new speakers work, the problem is in the speaker system. If it still has low output, you need to check the inputs as described above with a known-working deck and RCAs.

Amp plays but cuts off and on:

Attach volt meter to power and ground terminals at the amplifier.

Set the meter to peak hold (max/min) and display "minimum DC voltage".

Run the system until the amp shuts off and check the voltage. If voltage has dropped below 10 volts at any time, check all wiring.

Leave the meter positive on the battery wire and use a good, clean ground point on the vehicle and test again. If voltage has a higher reading than before, the problem is in the ground connection.

If it has the same voltage, work your way back to the battery; testing at any and all connection points. I.e. distribution blocks, capacitor, fuses, etc.

If at any point voltage goes up, you have found the voltage drop point.

Single vs. Multiple Drivers

2009-08-18T18:49:00.000-07:00

There are advantages and disadvantages to either approach. For this, let's consider a scenario where the cone area of a single driver is equal to the cumulative cone area of multiple drivers: An example of this would be a single 10" woofer with an Sd of 50in^2 versus a pair of 8" woofers with an Sd of 25in^2 each.

The single driver advantage: Linearity. A single driver system isn't subject to the acoustic or electrical forces countering in phase--even if by a fraction of a degree--which typically occurs when multiple pistons share a common space or when multiple inductors share a common circuit.

The single driver disadvantage: It has been my observation that a single larger driver will typically exhibit higher equivalent air compliance (Vas) than the combined compliance of two smaller drivers. This can translate into higher Vb requirements.

The multiple driver advantage: Assuming that the motor structure is the same on both the 8" and the 10" model, the immediate advantage is twice the motor for every square inch of cone area, twice the power handling, and more end-impedance versatility.

The multiple driver disadvantage: As stated above, using multiple independently actuated pistons increases the risk of the electro-mechanical forces countering one another. This is particularly evident with high Qts drivers.

The Perfect Subwoofer Box

2009-07-23T19:36:00.000-07:00

We often hear talk (specially in car audio) about certain boxes being RIGHT for certain woofers. Many folks talk like a given woofer wont even play at all if the box size is not exactly perfect!

What is perfect?

Manufacturers often recommend a certain box for their speakers.

Computer box programs can PICK the box size (or tuning) that works best(?) with the woofer if you input the Thiele/Small parameters.

Is the box size the manufacturer recommends perfect? How can it possibly be perfect when they don't even know what kind of car your installing the box into? We all know the car will change the sound (this is called transfer function)! How can they possibly choose the perfect box size? Many times the speaker manufacturers recommendation is chosen not for perfect sound but for an average that might work well in the average car. Many times they might recommend the box that's easiest to build for beginners or small (since many folks like woofs that work in small boxes) or sealed instead of vented because it is less likely for you to blow your speaker in a small sealed box than a large vented box! (if you blow your speaker (a) they might have to replace it. (b) the company might get a reputation for lousy speakers if they blow a lot) Sure, the manufacturers recommendation will probably sound great! But perfect??? Is the manufacturers recommended box size really right for you?

Is the box size provided by computer programs perfect? Again, how can it be unless they take into account the transfer function of the car??? I don't know of a current popular program that does! Most computer programs will calculate a box for you with the lowest response and with the least ripple. In car audio, this many times IS NOT the best! Sometimes (specially in SPL competitions) the ripple the computer program tries to avoid might actually be an SPL or bass boost! Or for an SQ car, a slight ripple (inaudible, an may likely be made up for by the cars transfer function) might get you much deeper bass... Is the computers recommendation the perfect box? Is the computer programs recommended box right for you?

How bout the difference in CUSTOM made boxes vs PREFAB boxes?

Most real car audio enthusiasts would never consider a PREFAB box, we all know the custom built boxes are far superior sounding... BUT ARE THEY REALLY?

From my experience there is a great amount of BADLY BUILT custom boxes being built! Built so badly in fact that for many cases a prefab box would be miles better!

A prefab box could be better than a badly built custom box! I have heard some darned good systems with prefab boxes and some very poor systems with custom built boxes.. It's important if your gonna pay high dollar for an installer to build you a custom box that the installer be good at building boxes or you might just as well have spent your money on a pre-fab and spent the left over money on something else.

PLUS, since we mentioned installers, how many really have any background in speaker design? Many claim to be experts, but in the real world most installers just build the so called custom boxes with no AUDIO PHYSICS in mind. So for a custom box, its important the installer be not only a carpenter but also an expert at loudspeaker box design... Or a pre-fab box might be the better choice! ;-)

And, in reality, there is no PERFECT box, and to really custom build a box to perform as good as possible in a given vehicle it requires huge stacks of expensive test equipment, lots of woodworking tools and saws, and building, testing then rebuilding and retesting, and rebuilding and retesting again and again and again until no more good is achieved. This is done only by a few crazy competition gurus or a few nutty hobbyists, certainly NOT for the average car audio guy, or even the average installer...

So, I think it would be safe to say most so called perfect boxes are no where near perfect, they can all be improved on. And even if they were perfect, putting them in a car will change them, even the direction the box fires in the car can have an effect!

And it makes me laugh when I hear a fellow say something like " the manufacturer recommends 1.5cu ft for this speaker, it wont work in 1.25cu ft!"

Sure it will!
If that's all the space you have,
build it,
play it,
enjoy it!

There are so many variables involved there is a chance the NON-PERFECT box might even sound better than the so called perfect one! Try it ;-)

Enjoy!

Mapping the Transfer Function

2009-07-23T19:34:00.000-07:00

Putting a speaker in a vehicle (or room for that matter) will make the speaker sound different. This is caused by reflections, absorptions and resonance's that exist in that car. This change is called the transfer function.

All cars have a transfer function, typically the most noticeable change to speakers when placed in a car is MORE BASS. More bass is inherent because the car is like a box, an enclosed space that promotes reinforcing reflections of the bass sounds (because the bass waves are long enough to be reflected and still be close enough to in phase and reinforce)....

But the transfer function is more than just a change in bass, it also can cause major changes in the midrange speakers because of the major glass surfaces for the sound to bounce off of! Or the high frequency sounds from the tweeters can be absorbed into the headliner or car upholstery (intentionally sound absorbent by the car manufacturer to absorb road noise)...

So, we cant easily change the transfer function, but we can map it, and then build our system to take advantage of our cars transfer function.

To map the transfer function you will need a Speaker box, a CD with test tones or an audio test generator or a pink noise generator and a decibel meter. There are several CDs available with test tones, I prefer the tone generator but they are fairly expensive and hard to find an install shop with one, pink noise is OK but pink noise generators are probably just as hard to find as audio generators. And for a decibel meter Radio shack sells one for about $30 that will work. Oh, and a piece of graph paper to write down your results.

First, lets map the speaker box. Take your speaker box outdoors in the back yard and aim it away from the house to minimize reflections, hang the SPL meter or microphone for it a few meters in front of the speaker box. Fire up your test tones and set the volume level where the SPL meter gets a reading on most of your test tones (if the low ones don't register don't worry), but not too loud, we don't want to damage the test speaker! Now without touching the volume control, run your test tones and write down on your graph paper the SPL at each tone. You can even make a graph on the graph paper if you want to.

Your results is the frequency response of your test speaker!

Lets put this box in the car and do the test again and see what changes!

Set the test speaker in a nice location, preferably close to where the real speakers will go later. Hang the microphone in the center of the car near where your ears would be if you were driving, and run through the test tones again, reading the SPL meter and writing down the results on the graph paper.

When you done, subtract the back yard numbers from the in car numbers for each frequency and write down your results. For instance, if you had 90dB at 120Hz in the back yard and 95dB in the car then (95-90=5) write down 120Hz=+5dB, and do this for every frequency you mapped. Some frequencies may have negative numbers, this is OK... When your done, you should have a series of frequencies=numbers something like this: 20=+4, 40=+6, 80=+12, 120=+3, 200=0, 400=-3, 600=-4, and so on...

This is your transfer function, you can now look at any frequency and tell what
your car is going to do to ANY SPEAKER you install.

Simple....

Dual Battery Wiring

2009-05-27T19:33:00.000-07:00

WIRE 1

This POS+ wire connects the two batteries' positive posts. This wire allows the rear battery to receive the charge from the alternator, just like the front battery receives. Without this wire, the rear battery would not maintain a charge.

WIRE 1 should be at least 1/0 awg wire. The reason why is that when batteries are connected together, they will instantly equalize in voltage. This can be hundreds of amps of current that is passed. Anything smaller than 1/0 awg wire is likely to be too small to transfer these high currents.

If you intend on pulling more than 300A of current across WIRE 1, you should add an additional run of 1/0 awg for each additional 300A of current you intend on pulling. So if you plan on pulling 600A, you would need two runs of 1/0 awg minimum. The more runs of 1/0 awg you have, the less voltage you can expect to lose due to resistance.

WIRE 2

This POS+ wire connects your amp(s) to your rear battery. This wire should be sized based on the input of your amp(s). If your amp has a 4 awg input, this should be a 4 awg wire. If your amp accepts 1/0 wire, then this should be a 1/0 awg wire.

If you decide that it is better for your setup, you can choose to use a distribution block between the battery's POS+ post and the amps' POS+ inputs. Some people prefer to use a distro block, but it is easier in my mind to simply run the wire directly from the POS+ post to each amp, in effect using the battery as the distro block. There is no right or wrong here, it is up to you to decide.

WIRE 3

This NEG- wire connects the two batteries' negative posts. This wire size should be identical to the size (and quantity) of WIRE 1. So, if you have two runs of 1/0 awg being used for WIRE 1, then you will need two runs of 1/0 awg for WIRE 3 as well.

Some people will argue that using the chassis instead of wire for your NEG- (grounds) connections is fine, but when you have multiple batteries, that is no longer going to be sufficient in most cases. If your car does not have one solid piece of steel running the length of the car, then you will have multiple pieces of steel that are welded together. Steel, as you well know, is a poor conductor when compared to copper (or other highly conductive metals). The conductivity of steel is highly reduced when welded together with another piece of steel. Imagine the weld as a speed bump.

Now the other issue here that is frequently overlooked is that as you begin to draw more current over a conductor, the impedance will actually rise. So simply measuring the resistance of your chassis without a current draw is pointless.

WIRE 4

This NEG- wire is to connect the NEG- connections on your amp to the NEG- post of the rear battery. It is important that this wire matches the size (and quantity) of WIRE 2. Again, just like with WIRE 2, the size of this wire should be determined by your amps' inputs.

Some people again would tell you to not wire this to the battery, but instead to the chassis. This would be OK if you did not have a rear battery and you had a very small amp. But since this discussion is assuming the rear battery is installed, you need to wire the NEG- connection for the amp directly to the battery.

WIRE 5

These wires are to ground each battery to the chassis for devices that may not have a NEG- wire running directly, but are still pulling power from the battery. A good example would be lights or other chassis grounded devices.

One last wire that is not shown, but would fall under the WIRE 5 category would be a wire from the front battery NEG- post to the engine block. This in essence would be the NEG- wire to the alternator, since the engine block is electrically connected to the alternator. If your alternator in fact has a NEG- post, of course the wire should connect there and not at the engine block.

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And now on to the fuses. Each fuse shown above serves a specific purpose. There are some people who live life on the edge and feel they are a waste of money. There are others who claim that they affect voltages in your vehicle. I am neither of these. I like feeling safe and secure knowing that my electrical system is protected by a fuse. These fuses will not only protect you from improper wiring, but also protect you in case of an accident that shorts out a POS+ wire. Also, good ANL fuses have very little added resistance, so the voltage drop across a fuse is usually not measurable.

FUSE A

This fuse should be located as close to the POS+ post of the front battery as possible. This fuse should be rated to match the current rating of WIRE 1. If you are using a single run of 1/0 awg wire for WIRE 1 and it is rated up to 300A, then FUSE A should be rated at the same 300A.

What FUSE A does is protect your wire from transferring more current (amps) than it is rated for. In the case of a short circuit in the middle on WIRE 1, the front battery will try to push all of it's energy through WIRE 1 to that short. When this happens, the amount of current will exceed the fuse value and cause the fuse to blow. When the fuse blows, the short is alleviated and no more current will pass along WIRE 1 from the front battery.

If the fuse would not have blown, the excessive amount of current would have exceeded the capacity of WIRE 1, which would have caused a fire.

FUSE B

This fuse does the exact same thing as FUSE A with the exception that it protects WIRE 1 from the current coming from the rear battery. If WIRE 1 were to be shorted, there is a potential for energy to flow from both batteries. A fuse on both ends of WIRE 1 is essential. Again it should be located as close to the POS+ post of the rear battery as possible.

And there is no reason to use only one of these two fuses here on WIRE 1. If you don't have both FUSE A AND FUSE B, then you are not protected from a short. So don't think that having one of the two is going to help you. Unless you have both, you are not protected at all.

FUSE C

This fuse is intended to protect WIRE 2 from to much current. Just as with WIRE 1 and FUSE A & B, you are going to match FUSE C with the current rating of WIRE 2. So if your amp accepts 4 awg wire, WIRE 2 should be 4 awg. If your 4 awg wire is rated up to 125A, then FUSE C should be 125A.

Choosing the Correct Port Tuning

2009-05-22T18:44:00.000-07:00

Tuning of a ported subwoofer box is determined by a combination of port area, port length, and net volume of the subwoofer box. Tuning changes the frequency at which the frequency response peaks (is loudest) and can change the way a subwoofer box sounds in your setup. Your tuning choice will be determined by the goal of your system install.

If you're looking to achieve an SPL setup your car (getting as loud as possible), you'll want to tune fairly high. High tuning for SPL is usually somewhere around 45Hz or possibly higher. At this high of tuning, the sound quality will not be very good, but it will be louder than if you were to tune low.

A SQ (sound quality) based setup will call for a tuning fairly low - even down around 25Hz. This will also allow you to hit the ultra-low notes with your system. Lower-tuned boxes produce better sound quality, more like a sealed box. The downside to lower tuning is that it flattens the frequency response, which will cause the box to lack the boost around the tuning frequency.

To achieve a good mix between SPL and SQ with a ported box, we have found that it's good to be in the lower 30's for tuning. If you tune up around 35Hz, you'll get a fair amount of SPL out of the box and still have fairly good sound quality. If you tune closer to 30, the box will yield better sound quality but have a little less output than the 35Hz. A range between 30 and 35 Hz is generally good for most general setups.

If you want SPL, tune high. If you want SQ, tune low. If you want somewhere in-between the two, we have found a good tuning is right at 33Hz. This is why we default the port tuning to 33Hz on our customization pages for our ported enclosures. When choosing a ported subwoofer box, the freedom to tune the enclosure is a great way to get your system sounding the way you want it to sound.

Quad DVC Subwoofer Wiring

2009-05-22T18:36:00.000-07:00

Parallel/Parallel DVC Subwoofer Wiring:

* Four 4 ohm DVC subwoofers = 0.5 ohm amplifier load
* Four 8 ohm DVC subwoofers = 1 ohm amplifier load

Series/Parallel DVC Subwoofer Wiring:

* Four 1 ohm DVC subwoofers = .5 ohm amplifier load
* Four 2 ohm DVC subwoofers = 1 ohm amplifier load
* Four 4 ohm DVC subwoofers = 2 ohm amplifier load
* Four 8 ohm DVC subwoofers = 4 ohm amplifier load

Parallel/Series DVC Subwoofer Wiring:

* Four 1 ohm DVC subwoofers = 2 ohm amplifier load
* Four 2 ohm DVC subwoofers = 4 ohm amplifier load
* Four 4 ohm DVC subwoofers = 8 ohm amplifier load
* Four 8 ohm DVC subwoofers = 16 ohm amplifier load

Triple DVC Subwoofer Wiring

2009-05-22T18:32:00.000-07:00

Parallel/Parallel DVC Subwoofer Wiring:

* Three 4 ohm DVC subwoofers = 0.67 ohm amplifier load
* Three 8 ohm DVC subwoofers = 1.33 ohm amplifier load

Series/Parallel DVC Subwoofer Wiring:

* Three 1 ohm DVC subwoofers = 0.67 ohm amplifier load
* Three 2 ohm DVC subwoofers = 1.34 ohm amplifier load
* Three 4 ohm DVC subwoofers = 2.67 ohm amplifier load
* Three 8 ohm DVC subwoofers = 5.36 ohm amplifier load

Parallel/Series DVC Subwoofer Wiring:

* Three 1 ohm DVC subwoofers = 1.125 ohm amplifier load
* Three 2 ohm DVC subwoofers = 2.18 ohm amplifier load
* Three 4 ohm DVC subwoofers = 2.45 ohm amplifier load
* Three 8 ohm DVC subwoofers = 2.82 ohm amplifier load

Dual DVC Subwoofer Wiring

2009-05-22T18:27:00.000-07:00

Parallel/Parallel DVC Subwoofer Wiring:

* Two 1 ohm DVC subwoofers = 0.25 ohm amplifier load
* Two 2 ohm DVC subwoofers = 0.5 ohm amplifier load
* Two 4 ohm DVC subwoofers = 1 ohm amplifier load
* Two 8 ohm DVC subwoofers = 2 ohm amplifier load

Series/Parallel DVC Subwoofer Wiring:

* Two 1 ohm DVC subwoofers = 1 ohm amplifier load
* Two 2 ohm DVC subwoofers = 2 ohm amplifier load
* Two 4 ohm DVC subwoofers = 4 ohm amplifier load
* Two 8 ohm DVC subwoofers = 8 ohm amplifier load

Parallel/Series DVC Subwoofer Wiring:

* Two 1 ohm DVC subwoofers = 1 ohm amplifier load
* Two 2 ohm DVC subwoofers = 2 ohm amplifier load
* Two 4 ohm DVC subwoofers = 4 ohm amplifier load
* Two 8 ohm DVC subwoofers = 8 ohm amplifier load

Single DVC Subwoofer wiring

2009-05-22T18:25:00.001-07:00

Parallel DVC Subwoofer Wiring:

* One 1 ohm DVC subwoofer = 0.5 ohm amplifier load
* One 2 ohm DVC subwoofer = 1 ohm amplifier load
* One 4 ohm DVC subwoofer = 2 ohm amplifier load
* One 8 ohm DVC subwoofer = 4 ohm amplifier load

Series DVC Subwoofer Wiring:

* One 1 ohm DVC subwoofer = 2 ohm amplifier load
* One 2 ohm DVC subwoofer = 4 ohm amplifier load
* One 4 ohm DVC subwoofer = 8 ohm amplifier load
* One 8 ohm DVC subwoofer = 16 ohm amplifier load

Quad SVC Subwoofer Wiring

2009-05-22T18:21:00.000-07:00

Parallel SVC Subwoofer Wiring:

* Four 2 ohm SVC subwoofers = 0.5 ohm amplifier load
* Four 4 ohm SVC subwoofers = 1 ohm amplifier load
* Four 8 ohm SVC subwoofers = 2 ohm amplifier load

Series SVC Subwoofer Wiring:

* Four 1 ohm SVC subwoofers = 4 ohm amplifier load
* Four 2 ohm SVC subwoofers = 8 ohm amplifier load
* Four 4 ohm SVC subwoofers = 16 ohm amplifier load

Triple SVC Subwoofer Wiring

2009-05-22T17:43:00.000-07:00

Parallel SVC Subwoofer Wiring:

* Three 2 ohm SVC subwoofers = 0.67 ohm amplifier load
* Three 4 ohm SVC subwoofers = 1.33 ohm amplifier load
* Three 8 ohm SVC subwoofers = 2.67 ohm amplifier load

Series SVC Subwoofer Wiring:

* Three 1 ohm SVC subwoofers = 3 ohm amplifier load
* Three 2 ohm SVC subwoofers = 6 ohm amplifier load
* Three 4 ohm SVC subwoofers = 12 ohm amplifier load

Dual SVC Subwoofer wiring

2009-05-22T17:18:00.000-07:00

Parallel SVC Subwoofer Wiring:

* Two 1 ohm SVC subwoofers = 0.5 ohm amplifier load
* Two 2 ohm SVC subwoofers = 1 ohm amplifier load
* Two 4 ohm SVC subwoofers = 2 ohm amplifier load
* Two 8 ohm SVC subwoofers = 4 ohm amplifier load

Series SVC Subwoofer Wiring:

* Two 1 ohm SVC subwoofers = 2 ohm amplifier load
* Two 2 ohm SVC subwoofers = 4 ohm amplifier load
* Two 4 ohm SVC subwoofers = 8 ohm amplifier load
* Two 8 ohm SVC subwoofers = 16 ohm amplifier load

Single SVC Subwoofer Wiring

2009-05-22T17:10:00.000-07:00

SVC Subwoofer Wiring

* One 1 ohm SVC subwoofer = 1 ohm amplifier load
* One 2 ohm SVC subwoofer = 2 ohm amplifier load
* One 4 ohm SVC subwoofer = 4 ohm amplifier load
* One 8 ohm SVC subwoofer = 8 ohm amplifier load

Hifonics Release 09/10 range of Brutus Amps

2009-04-27T04:12:00.000-07:00

Maxxsonics' new Hifonics Brutus amplifier line up offers the most versatile and comprehensive Super D-Class series than ever before.

For years, Brutus BXI amplifiers have been recognized the world over as some of the best subwoofer amplifiers in their class. The new Brutus amps are 1-Ohm stable, but also run at 4- or 2-Ohms for a much tighter bass response.

Simply put, watt for watt, a Brutus amplifier produces more output with less impact on a car’s battery and charging system, than many other amps available today. Translated into cost, that’s more wattage output with less battery current used, equaling more watts per dollar.

For SPL, nothing compares to the Super D-Class grade microprocessors developed exclusively by Hifonics. In relying on this super-speed enhanced chip-set, Brutus BXI amplifiers offer higher current capacities and more precise digital to analog conversion. The result is very low distortion, even at high listening levels. For high performance sound, Hifonics doesn’t miss a beat by also including a Brutus A/BClass amplifier in the line.

According to John Studley, Vice President Product Development, “Our Brutus amps not only sound great, but look great with an extruded aluminum chassis and an illuminated Hifonics logo. We spend just as much time and detail on the technology of our products as we do on the exterior.” Studley concluded by saying, “Even the Hifonics logo was designed so that it has a soft haloed illumination that is tasteful and not distracting.”

See the Brutus series and complete line up from Hifonics at the Maxxsonics booth, North Hall 1809 at CES.

MODEL/ RMS POWER /MSRP

A/B-Class

BXI610 1 x 150 W @ 4 Ω, 1 x 300 W @ 2 Ω, 1 x 600 W @ 1 Ω $449.95

D-Class

BXI1210D 1 x 450 W @ 4 Ω, 1 x 900 W @ 2 Ω, 1 x 1200 W @ 1 Ω $649.95

BXI1610D 1 x 550 W @ 4 Ω, 1 x 1100 W @ 2 Ω, 1 x 1600 W @ 1 Ω $799.95

BXI2010D 1 x 650 W @ 4 Ω, 1 x 1300 W @ 2 Ω, 1 x 2000 W @ 1 Ω $999.95

BXI2610D 1 x 850 W @ 4 Ω, 1 x 1700 W @ 2 Ω, 1 x 2600 W @ 1 Ω $1199.95

Understanding The Basic Car Audio Capacitors

2009-03-08T23:18:00.000-07:00

The audio system in our cars is an assortment of different parts. Each and every part in the system performs a specific function. It is with the co-ordination of all the parts, that you can hear the system play those fantastic tracks as you drive along. In the entire system, car audio capacitors have a significance of their own.

What are car audio capacitors?

Car audio capacitors are basically power storages in the car. These capacitors accumulate that power which is essential for the amplifier to produce great sounds. You can hear the booming bass sounds and songs with that much needed punch only because of audio capacitors. Car audio capacitors are also known as stiffening capacitors.

More on car audio capacitors

• Audio capacitors accumulate power whenever it is not required. This power is released when the demand for power exceeds the supply capacity of the power system of the car.

• Audio capacitors are necessary to supplement the regular power supply of the car in order to ensure the smooth functioning of the amplifier. Car audio capacitors usually range from 0.5 farads to 3 farads.

• You have to install a car audio capacitor that complements your amplifier. It is also necessary to place the capacitor as near as possible to the amplifier. For 500 RMS of power output, it is necessary to have an audio capacitor of 0.5 farads.

• There are also digital audio power capacitors. These can also be installed in cars. A digital audio capacitor (usually from 1.5 farads) consists of a turn on and turn off circuitry along with a 24-volt DC.

If you car lights dim when your car audio system produces a deep bass note, then your amp will be greatly helped with a car audio capacitor.

How do I know I need A Capacitor?

Before installation, it's often difficult to predict whether or not a capacitor will be beneficial to you. It's generally best to install the audio equipment prior to making the determination, so that you can address which symptoms need to be remedied and assess the severity of the symptoms. This will not only help you decide whether or not you need a capacitor, but also how much capacitance would be beneficial.

The most common symptom in need of added capacitance is headlight dimming (and sometimes dimming of the interior/dash lights). It's caused by a drop in system voltage associated with excessive current draw. While there may indeed be several loads drawing substantial amounts of current from the electrical system (eg. heat, AC, and so forth), it's usually the transient draws that best manifest themselves in noticeable dimming. This is partly because our visual systems are most sensitive to detecting rapidly changing intensity levels rather than steady absolute differences.

Once you've assessed whether or not the dimming is noticeable (and sufficiently annoying), you must decide whether a capacitor is warranted or if you'd be better served by upgrading the alternator.After initially having your alternator and battery checked out (some places will do this for free), the choice should be based on the severity of the dimming.

A commonly-used estimate for determining the appropriate size capacitor is 1F/kW (one farad per kilowatt). For example, a system running at300W would need a 0.3F (or 300,000uF) capacitor. However, there are several variables at play here, including the capabilities of the vehicle's electrical system (which generally varies from idle to higher RPMs), the efficiency of the amplifiers, and the listening habits of the user (ie. the tone controls and the type of music).

These factors should all be considered when making the determination. Moreover, the voltage drop can be so severe that added capacitance is nothing more than a band-aid. That is, even several Farads of capacitance would not be able to sustain the voltage for as long as the drop persists. This Is when an alternator upgrade may be in order.

How to wire a capacitor?

You can refer to a recent post on wiring Here

Planning Your Audio System

2009-03-08T22:57:00.000-07:00

This part of the game can be fun or disappointing depending on what you can do. First I'm going to give you an example system that I believe includes everything you need to have a pretty good system. After that I will show you how to make compromises and leave out parts that may not be as important to you to keep your system within your budget. If you want to go beyond my basic system you probably already know more than what this site can tell you. Also, you do not have to get everything at once. I put my system together over a few years. With a little planning you can upgrade your system in steps and that way its like getting a new system every time you change something instead of getting everything at once!

Basic System: This is my opinion only but I think that a good system should start off with a good head unit that either has a CD player and/or is connected to a CD changer. A good system sounds best when playing CDs, tapes just do not cut it. Next I think component sets are made with fewer compromises than coaxial speakers so I suggest getting a good mid-range/tweeter set for the front. Head units generally do not put out enough clean power so you will want an amp to drive the component set. In the rear where you only need some "fill" for ambiance you can get away with cheaper coaxials and set their level lower than the fronts to keep the sound stage in front. A modest (50x4) 4 channel amp is a good choice here for powering the component set up front and the rear speakers. You could use a good 2 channel amp and run the front and back in parallel on the amp but it would harder to adjust the level between them. Mid-ranges sound best when they do not play bass so you will want a 2 way electronic crossover and use the high pass output to drive your 4 channel amp. I did not forget the bass! Most people are happy with a single 10" woofer or a pair of 12"s. Use an appropriate enclosure and a big amp (at least 75x2, preferably even more). Throw in installation and wiring accessories (like fuses and distribution blocks). Here's an approximate price break down of what this costs in my area. Your prices may be significantly different.

head unit: $300-$500
4 channel amp for highs: $250-$400
2 channel amp for lows: $300-$700
sub(s) (1-10" to 2-12"): $150-$450
enclosure for sub(s): $0 (free air) - $250 (custom)
component set: $200-$500
coaxials for rear fill: $100-$400
crossover/equalizer: $100-$500
wiring and accessories: $50-$250
installation: $0 (do it yourself) - $100 (basic)

This comes out to $1450-$3950! I realize that this is a lot of money and that most people do not spend nearly this much money on their car stereo. However, the things listed above are what I feel is necessary to have a system with only a few compromises. If you are less concerned about highs, get coaxials in front instead of the component set and power them off of the head unit and use some bass blockers on them. This will save you about $400. Getting a bargain head unit can save you some money as well. If you are really not into bass much you can forgo all the bass related equipment and run your component set full range. This will still give you clean sound but not much bass. However, you will save $550-$2300. I would start with what I have listed above and take out parts you do not care about as much. Only you know what kind of system you can be happy with.

Please do not email me asking for recommendations about specific brands. There is a lot of equipment out there that I have not used so I will not comment on them. I am happy with the components that I have but that is as far as I can go with recommendations. When buying equipment try to spend time listening to it before you buy, especially with speakers. Also try to use equipment that is similar to yours when listening in a store. As for amps, it costs money to build a good amp so if you see some awesome price on an amp you have never heard of, it is probably a piece of junk. Stick with good names with amps.

Finally, if you are on a budget (aren't we all?) it works better to upgrade in steps. The most important thing is to have a car audio system that sounds good to you not someone else. If you are happy with just changing the factory speakers and stopping there then just do that. There is a level when that new amp or speaker is not going to make a difference so it is not necessary to always upgrade. There are people who think my system is terrible but it works well enough for me and anything else I do to it would be a minor gain and not worth my trouble. Do not let a salesperson talk you into something you do not need! Good luck!

Pioneer AVIC-F900BT - Navigation Review

2009-02-20T23:20:00.000-08:00

The Latest Version Of The AVIC Is Loaded With Features At A Budget Price

MSRP: $1,100
A few months ago I had the opportunity to testdrive the new AVIC F-series of navigation/multimedia source units in one of the various demo vehicles that Pioneer arranged for the press preview. The F-series basically replaces the D line, which ended with the D3. Like the latter, the new products are priced low enough that, value-wise, it would be a much better deal for people who want navigation to buy an AVIC F than one of the PNDs from the big three nav makers. After all, the AVIC-F900BT is superior in many ways to the D-series and costs only a little over a grand, for which you get a lot of built-in media functionality, along with the navigation.

There were some glitches in the pre-production models at the preview- some of the same issues some users have experienced with the production models. But the new AVICs seemed very promising, and I looked forward to having the chance to use one of various source units in the line.

Affordable All-In-One

Ostensibly, the AVIC-F900BT that I received for review is the complete package. The double-DIN unit with a 5.8-inch touchscreen has map data (from TeleAtlas) completely contained on a flash drive. A lot of nav users will be glad to hear that DVD-ROMs are no longer necessary. So you have navigation, DVD playback, and music galore via disc, iPod, a thumb drive, or an SD card, not to mention HD Radio and satellite radio with adapters, which have to be purchased separately. Conveniently, there's also a mini-jack connection on the face of the source unit. The 3.5mm mini-jack aux input is a great feature, but that too requires Pioneer's CD-RM10 cable in order for you to connect an A/V device to the unit.

This AVIC also has you covered for Bluetooth. You can connect three phones and the F900BT will store 400 contacts; it allows you to be totally hands-free. That applies for accessing music from your iPod as well. The F900BT has voice recognition software (called the VoiceBox Conversational Voice Search Platform) that makes it possible for you to select music folders and tracks by voice command. As with a lot of voice command systems, it can have problems understanding your requests. Be it the Ford Sync, the AVIC-Z3, or a separate aftermarket Bluetooth kits-I've yet to find a product that works as advertised in terms of the voice recognition quality. In theory, you can make calls, select tracks off your iPod, and even make some navigation commands just by using your voice. It's not perfect, but it's better than not having the option. Caveats or not, the above features are a pretty amazing collection of options. They may be found on other pre-existing (and separate) products, but at $1,100, this seems to be a real steal.

Add the option for MSN Direct for traffic information, movie time listings, and a list of the gas stations with the best per gallon prices and more, and you can see why I say that the F900BT is the complete package. MSN Direct is a must-have. And the GOOG-411 service is a nice add-on feature. You can use it to search for and connect to local businesses via a toll-free number. The only thing that is important to me that the unit lacks is the ability for DVD-Audio or, say, SACD playback. But then when was the last time you actually bought a disc in one of those formats? OK, not big misses there. On the audio side, the F900BT takes care of business, and will probably be robust enough for most music fans. There are seven preset EQ curves; and you can make a couple of your own custom EQ settings. There's also a three-band parametric EQ that allows you to select the Q factor, a highpass filter, adjustable loudness, and SLA (source level adjustment) to keep your volume settings consistent over different sources.

Navigating Potential

The main selling point for most consumers, of course, is going to be the navigation. The map data covers the U.S., including Alaska and Hawaii (and Canada) on a 2GB flash drive. That contains the usual list of POIs as well. The graphics are fine and the lane departure indicator is terrific, but the voice guidance could have provided faster alerts to turns on surface streets and exits off freeways, for example. But the bigger problem was that accessing data can test your patience. Searching for a POI "around the current GPS location" requires a wait of a few seconds to get to the next menu window. Also, I looked for Nixon's library locally as a tourist attraction, but it wasn't listed on the search result. When I typed it in on another search I finally got the address. So there are some things you might think should be more intuitive than it is; however, I should add that I find this kind of problem a lot with various nav devices. What compounds the issue of an already slow system is something more fundamental: I counted anywhere from 30 to 60 seconds for the system to load when I started the car. The only thing I could do during that time was insert a CD and adjust the volume. Whether or not this is a big deal will depend on your level of patience. I just don't happen to have a lot of it.

There are issues such as the above that make what was potentially an amazing product a decent product instead. The lesser-than-average visibility of the monitor, especially during the day, the average touchscreen responsiveness and the flat, difficult-to-use volume knob also detract from what was a great concept: a multimedia navigation unit priced for the masses. Early adopters of the AVIC F-series have encountered problems with the Bluetooth, iPod functionality, and the system loading time. On the F900BT, I experienced dropped calls as well. To address the different problems Pioneer released a firmware update. You can go to the company's website, www.pioneerelectronics.com and go to the navigation section. There are explicit directions for downloading the firmware and for loading it via SD card to your F900BT or other F-series unit (the F500BT is excluded). You'll find that it will improve the performance of a product, making it that much more worth the price. And ultimately, at this price point (and that is the point) there isn't another product with as much to offer and that is as easy to use while being so feature-rich. The question is: How much is too much for a product with great and various capabilities that are countered by some functionality issues? There are always value or quality trade-offs when you buy things. I would suggest you go for your own testdrive to determine if the new AVIC is worth it for you. I should note that the latest shipment of AVICs have the firmware included, which should make your decision to buy a little easier.

Key Features

5.8-inch touchscreenMap data on flash driveVoiceBox for voice control of iPod and BluetoothMSN Direct (with subscription)Satrad (Sirius or XM) and HD Radio readySteering wheel control compatibility (optional, requires separate interface)DVD playbackSix-channel preamp outputs (front, rear, subwoofer)May need firmware update

How to Dial in Your Car's Audio System

2008-12-26T02:10:00.000-08:00

Level setting, done by ear, is more art than science. It can be done using an oscilloscope but since few people have one of those laying around we'll cover doing it by ear. Basically you want to start with the first component in the chain (the head unit) and work your way to the last component (the amplifier).

1. Start by turning all of the input level adjustment knobs (gain controls) on your components fully counter-clockwise (to their minimum setting). Set the tone controls (bass, treble, loudness) on your head unit to no boost (bass and treble level = 0 and loudness is off). If you have more than one RCA pair you will want to set each gain adjustment separately. Make sure your fader and balance controls are set to the channel you want to adjust first. This can be an individual channel if you have individual gain adjustments or a pair of channels if you have one gain for two channels.

2. Next set all of your equalizers settings (if you have an equalizer) to the center (detent) position so they produce no boost or cut. What we want is as pure a signal as possible.

3. Put in some good quality source material, preferably a CD with strong output and a clean recording. Hard rock would be a bad choice here. Try something cleaner, maybe acoustic, that you're familiar with.

4. Turn the deck's volume up slowly until you begin to hear distortion. When you hear it, stop and back off slightly until you no longer hear it. If you don't hear distortion, even when the volume is all of the way up then you have a quality head unit. That's what we're looking for.

5. Now with your head unit at maximum undistorted volume move on to the next component. Adjust it's input gain until you begin to hear distortion. Back off slightly.

6. Continue this process until you have all of the components in the chain at their maximum undistorted level.

7. When you reach the amplifiers you may need to wear earplugs to adjust them to their maximum level. As before, turn up the gain until you hear audible distortion. This should be audible even with earplugs in. But honestly, if you have to wear earplugs to listen the distortion level is probably not a factor :)

That's it. Play some music and verify that everything sounds right. Congratulations! You've just learned to properly adjust the settings on your car audio system.

Kicker WX10000.1 Warhorse

2008-12-18T20:07:00.000-08:00

MSRP $9,999.99
With dimensions measuring 35 inches by 17 3/4 inches by 3 3/4 inches and a total weight of 66 pounds, the Warhorse is a monster of an amp. On the other hand, it's about the same size as amps with much lower power output, say, around 3,000 watts. That raises the question of whether it's efficient enough to actually make its claimed 10 kilowatts of power.

Before I get into it, let's look at what we're working with. Kicker has rated this beast at 10,000 watts into a 2-ohm load, or 5,000 watts into a 4-ohm load. As far as the class, it's not D, AB, or anything else you might be familiar with. In fact, the operation of this amp is so unique that Kicker has applied for a patent so they can classify it. I'll do my best to explain all that, but in the meantime study up on Class D operation and pulse width modulation as a reference point.

The amp has the usual features you'd expect to find in a big subwoofer amp like 24dB/octave highpass and lowpass crossovers, 0 to 18dB of bass boost at 40Hz, and the absence of fuses. In addition, the Warhorse sports three ought-gauge power and three ought-gauge ground cable connectors, and two pairs of 8-gauge Anderson connectors for the speaker outputs. No, it's not a stereo amp-strictly mono.

Eight indicator lights on the control panel reveal several conditions. PWR illuminates when the amp is on and working properly. NET shows that you're connected to the optional WXRC remote control, which offers expanded crossover slope selections in addition to being able to make adjustments from the driver seat. There are also LED indicators for over-voltage, under-voltage, overheated and short-circuit. The X-BNDW light tells you that you have set the lowpass crossover lower than the highpass crossover, while the Service light lets you know that you probably need to get the amp back to the Kicker service department or at least call the tech support line.

The unit looks like an oversized black briefcase with extruded fins running the length of each side. The top is an engraved black aluminum plate with a molded plastic hood over the entry for the power cables. The cast endcaps house the cooling fans and provide a very structural look to the whole unit. The power and ground-all six ought-gauge cables-come into the amp at almost the center of the top plate. All other connections and controls are hidden halfway along the nearside heat sink under a matching cover plate.

Circuitry
Looking under the cover, the first thing you'll notice is the four planar transformers and the huge buss bars that run across the topside of the main circuit board. The transformers are about the size of your hand and resemble a stack of pancakes. The primary and secondary windings are stacked on top of each other rather than being several strands of wire intertwined. The turn ratio is 19 to 1, meaning there are literally 19 turns of flat wound copper for each secondary and one turn for each primary. The primary looks more like a big horseshoe-shaped PCB trace. Each planar transformer is rated at 5,000 watts for a total capacity of 20,000 watts.

The positive and negative power cables feed the transformers directly by way of the plated copper buss bars. The B+ power supply is stabilized by a total of 50 3,300F/105 C capacitors. That makes for a lot of instant juice on tap.
The entire backside of the heat sink is occupied by 64 MOSFETs, 16 for each of the four transformers. Normally, I'd call these devices "switchers" to drive the transformers and create the positive and negative rails, but this is where we deviate substantially from every other amp. These MOSFETs do actually drive the transformers, but not at a steady rate to create a "reservoir" of output power. They actually drive the transformers directly to the speaker outputs in a pulse-width modulation fashion. This effectively eliminates the section of the amp that would normally be called the "output" section, and also eliminates the efficiency losses associated with output sections, whatever class they may be.

Let's look at the input section. The analog music signal from your head unit enters the amp by way of a pair of gold-plated RCA connectors, and goes pretty much straight to a Texas Instruments DSP chip. There's plenty of support circuitry around the DSP. In fact, the input board is about 6 inches by 8 inches, but all of the processing goes on inside the chip. The gain, crossover, bass boost, and limiter controls are all single element potentiometers that feed reference signals to the DSP chip. In other words, they have no direct effect on the analog signal; they just tell the processor what you want it to do. Once the analog signal enters the DSP, there's no more analog signal until you get to the output filter at the speaker outputs. Because the crossovers and bass boost are handled in the digital domain, the curves are picture perfect and very precise.

Here's where things get even stranger. In a typical amp you have an input stage, a power supply stage, and an output stage where the first two stages work together to kick out the tunes. The power supply runs at a constant rate, creating a "reservoir" of power (called "rails") that's fed to the speakers through the output transistors as the input section commands. In the Warhorse, there's an input stage as usual, but the output and power supply stages are combined. Instead of creating a reservoir of power for the output stage to use, the DSP causes the power supply to actually create the output signal directly. Instead of running at a constant level, the power supplies are constantly going up and down (signal modulated) in response to the DSP to create the output voltage. There are no output transistors.

That's the conceptual picture, pretty much devoid of the details. At this point you may be thinking, "That's too easy" or "Why hasn't this been done before?" While the concept is easy, the execution requires a fairly powerful DSP, as well as a fairly powerful brain trust to program the DSP. On this scale (remember this amp puts out 10,000 watts), it also requires the planar transformers with specific coupling and power characteristics.

The DSP is in complete control of the transformers, running a constant pulse of 24kHz. That doesn't mean the transformers are creating a large 24kHz output signal, but that's the clock speed for the pulse-width modulation. When a signal comes into the DSP, it sends off/on pulses to the transformer switchers of the appropriate duration to create both the frequency and the amplitude of the output. In a pulse width modulation format the length of the pulse will correspond to the output voltage level, and in this amp the length of the pulses will be limited to 1/24,000 of a second. A maximum pulse (100 percent) will result in maximum power output, while a half-length pulse (50 percent) results in half power. At idle, there's zero current going through the transformers, but it's still happening at 24kHz.

This is where the amp is like a Class D amp. If the transformer is completely accurate (not possible, by the way) the output will consist of really large squared waves. In reality, the transformer will round these square pulses considerably, plus there's an output filter consisting of a coil and capacitor(s) to finish converting the squared pulses to nice round sine waves. The output filter coils in the Warhorse actually look just like large transformers that would be used in the power supply of a big Class AB amp.

So you now have output signal to feed your speakers, and it should resemble the analog input signal that came into the DSP to start with. The DSP takes feedback from the speaker outputs and makes real-time adjustments to the pulses to create a more accurate reproduction of the original signal, only lots bigger.

There are two separate sets of speaker outputs on the Warhorse, but they're not parallel. You have to use both of them and you have to use them on a dual voice coil speaker, one output to each coil of the speaker. One set handles the positive side of the wave and the other handles the negative side. The + and - labels on the amp correspond to the labels on the speaker's voice coil terminals. At full power this amp is making around 141 volts between 20Hz and 200Hz. Household AC is 120 volts at 60Hz. If you fed the amp with a 60Hz signal, you could probably use it as a backup generator for your house, so don't mess around with the speaker outputs when this amp is on.

Performance
The amp tested as advertised in all respects. The frequency response is exactly 20Hz to 200Hz at the -3dB points, though we used +0/-1dB for the test results. The crossovers and bass boost are exact as well, which is a direct result of the signal being handled in the digital domain by the DSP chip. Power at 14.4-volt input exceeded 10 kilowatts by 350 watts-the equivalent of a decent subwoofer amp. While 10,000 watts is pretty impressive, the fact that the WX10000.1 can deliver it with almost 90 percent efficiency is amazing. Class AB amps hover around 50 percent, so this amp can deliver almost twice the output power for any given power input. You can feed two of these amps for the price of one.

There was no indication on the scope of any turn-on or turn-off noise. Who needs a 10,000-watt turn-on pop?

Slew rate and damping factor have been omitted from this test due to the way the amp works and the importance of such specs for an amp of this size. Testing was complicated by the fact that the DSP is instantly responding to the output feedback. The compensation by the DSP resulted in a negative ratio for the damping factor. The precision of the DSP also resulted in a very low slew rate at the output, which corresponded very closely to the actual slope of a wave at 200Hz. In other words, we were only able to measure what the DSP was causing the amp to do, rather than what it might be capable of.

Manual
The owner's manual is a pretty comprehensive affair. In fact, I suggest you read the manual before purchasing the amp, just to make sure you're equal to the commitment. The manual is where you learn about having to build an electrical substation to feed the beast. Yes, I'm exaggerating but seriously, Kicker recommends no less than eight batteries of 800cca plus two alternators putting out 200 amps each. That's in addition to the battery and alternator just to run the vehicle. As well, you have to run ought-gauge cable everywhere to boot.

Besides the electrical requirements, and the structural mounting bracket, the manual shows several wiring configurations, and explains the controls clearly. The warranty is three months (consumer installed) or two years when installed by an authorized dealer.

Conclusion
Kicker has managed to break new ground here, and do it in a big way. The Warhorse is expensive, but it's intended for use in decibel machines and show systems. The retail dollars-to-watts ratio is a pretty high 97 cents, but using this amp will reduce the overall cost of batteries and alternators due to its high efficiency. Check out the Kicker Warhorse van making appearances around the country if you want to experience what this kind of power is all about.

Test Results
Output power @ 1% THD, 50Hz, 14.4 volts
Mono @ 4 ohms 1 x 5,494 watts
Mono @ 2 ohms 1 x 10,350 watts
Output power @ 1% THD, 50Hz, 12.5 volts
Mono @ 4 ohms 1 x 4,050 watts
Mono @ 2 ohms 1 x 8,052 watts
Distortion at rated power, 50Hz, 14.4 volts 0.66% @ 2 ohms
Input sensitivity 165mV to 5.2 volts
Frequency response (+1dB) 25Hz - 170Hz
S/N ratio (A weighted, below clipping, min. gain) >82dB
Idle current 3.5 amps
Maximum current consumption, unclipped 801 amps @ 10,350 watts
Efficiency at one-third power, lowest impedance 88%
Efficiency at full power, 1%THD, lowest impedance 89.7%
Crossover slope 24dB/octave
Crossover range, lowpass 50Hz - 200Hz
Crossover range, highpass 20Hz - 60Hz
Low-frequency boost +18dB @ 40Hz
Dimensions 35"L x 17.75"W x 3.75"H
Weight 66.8 pounds

Soldering Techniques

2008-12-12T18:21:00.000-08:00

Soldering is a simple efficient and reliable way to make electrical connections. The most common reason people are not successful in making good solder connections (joints) is that they do not properly heat the components which are being soldered. Some people apply the solder only to the tip of the iron. This will most likely result in a 'cold' solder joint. Cold solder joints will almost always fail. The only time that you should apply the solder directly to the iron is when the iron isn't conducting the heat to the parts. When the COMPONENTS being soldered are hot enough to easily melt the solder, you know the components are hot enough to make a good quality solder connection. Be sure to keep the soldering iron clean. The oxidized solder which will start to form on the outer surface of the tip of the iron is an insulator and will prevent good heat conduction to the electronic components. If you use a wet sponge to clean the iron, be very careful. If there is a large quantity of solder on the tip and you press hard on the sponge (compressing it a significant amount), as the iron slips off of the sponge hot solder may be thrown off of the sponge (and it still may be very hot). I think it may be better to use something like a coarse steel wool to clean the iron. I also believe that the wet sponge may significantly reduce the life of the tip.

Selecting a Quality Iron

If you want a really good iron, I would suggest that you buy a Weller WP35 iron. I have used them for a very long time and they are very reliable. A WP35 (approx $35) is a 35 watt iron which is suitable for almost everything that you will need to do in car audio or electronic repair work. DO NOT buy a $5 iron and expect it to last very long. The tips of cheap irons are usually just bare copper which quickly oxidizes and cannot properly conduct the heat to the components. The tips on the WP35 are steel clad copper which last for months at a time, even when they are used for more than 8 hours a day. The tips are also available in different sizes. The wider thicker tips are more suitable for soldering larger components.

Soldering Flux

Flux is used to help keep oxygen out of the connection and helps to float contaminants to the surface. It may also help to conduct the heat to the components. Virtually all solder designed for soldering electronics has a core which contains flux. When buying solder for electronics, make sure the flux is not an acid flux. Acid flux is used to solder non electronic components like sheet metal. Flux is also available in a paste form but I rarely use it.

Desoldering

If you have ever tried to remove electronic components from a circuit board (especially multi legged components), you know that it is difficult to remove the old solder without some help. The 2 least expensive, quickest devices to remove the solder are desoldering braid and the desoldering pump. Desoldering braid is simply a flux coated copper braid usually about .1"-.15" wide. To remove the excess solder with braid, you simply apply heat to the braid while the braid is in contact with the solder. The braid will wick the melted solder from the circuit board. The desoldering pump is a device which creates a vacuum to suck up the melted solder. The one I use has a spring loaded plunger which you 'cock' prior to each use. Then when the solder is melted, put the tip of the desoldering pump on the solder joint and release the plunger by pressing (depressing) the release button. For me, it works better if the iron is left on/in the solder while sucking the solder. This will result in a slightly shorter life of the desoldering tip but I have better results. I would recommend buying a 'Soldapult' brand desoldering pump. A large professional quality model is about $30 and will last a very long time. I've used mine professionally for about 5 or 6 years and they are still going strong.

Building with Acrylic

2008-11-19T17:48:00.000-08:00

Acrylic Sheeting/Plexiglas:

Acrylic sheeting is widely known as Plexiglas©. Plexiglass©, however, is the name given to acrylic sheeting manufactured by Atofina. The same acrylic type sheeting is also known by the names Acrylite©, Lucite© and Perspex©. From this point on, I'll refer to it simply as acrylic.

Before we go any farther... Do not peel the protective coating from the sheet until the last possible moment. Acrylic sheeting is very easy to scratch. It may be even easier to scratch than CDs.

Cutting Acrylic:
There are a couple of different ways to cut acrylic. Since my experience is mainly with thin acrylic sheeting (1/2" or less), that's what I'll cover.

Table/Circular Saw:
For rough cutting acrylic, you can use a table saw or a circular saw with a fine blade. Blades with fine closely spaced teeth (like those used for plywood) will work relatively well. Blades with widely spaced teeth (like the type used for cutting MDF) will cause a lot more chipping. I've used an Oldham B7254760 on a circular saw with good results. When using a hand held circular saw, use a guide to make sure you get a straight cut with minimal chipping. There are blades made specifically for cutting acrylic. If you're going to be cutting a lot of acrylic or are using very expensive (thick) material, you need to invest in a blade specifically designed for cutting plastics and laminates.

Jig Saw or Band Saw:
Jig saws can be used to cut acrylic when you need something other than a straight cut. To reduce the work of cleaning up the cut, use the finest blade that you can find. Blades with reduced depth (like those used for scroll work - shown below) will work best due to less friction and less resistance when turning the blade. You'll have to experiment with cutting speed to see what works best. Too much pressure can cause excessive chipping. Going too slow may cause the acrylic to melt. If the acrylic melts when cutting, use a light lubricating oil. Have someone apply the oil to the blade as you're making the cut. DON'T use an aerosol dispensed oil. The propellant may be flammable and may be ignited by the jig saw motor. I've had good results with the blade shown below.

Router:
A router can be used to cut acrylic for either straight or curved cuts. For curved cuts, you'll want to use a router with a collar and a guide (pattern or jig made with 1/4 inch plywood). You'll want to rough cut the material within ~1/8 of an inch of the desired finished shape. Trying to cut too much acrylic will lead to melting of the material. Again, you'll have to experiment with the speed of the cut. To prevent chipping, make sure the blade is not allowed to break contact with the cut edge. If it does break contact with the material and you push the router blade back into the edge too quickly, the cutter may chip the acrylic. You also must make sure you have a sharp bit (carbide recommended) to prevent melting of the material. Again, you'll have to experiment to see what works best for you.

Score and Break:
Thin acrylic sheets (less than ~1/4") can be cut much like regular glass. Instead of using a hardened wheel to chip a line in the glass, you'll use a scoring tool to cut a deep scratch in it. The cutting edge of the scoring tool looks something like a single tooth of a table saw blade (but much thinner). You apply pressure to the tool and drag it along a straight edge guide (which should be clamped securely in place to prevent it from moving). You need to continue scoring the acrylic until the cut is ~1/8 of the way through the material (it may take 20 passes on 1/4" thick stock). After that's done, you'll have to clamp it down on the edge of a table (or something similar). The edge of the table needs to align with the cut. The edge of the table needs to be perfectly square (a radiused edge on the table won't provide the proper stress along the desired cut line). It needs to be clamped very securely so that it can not flex or move. You'll then apply pressure to the piece that's beyond the edge of the table until it snaps. If it was cut deeply enough, it will break cleanly along the desired line. If it was not cut deeply enough, the cut (on the side opposite the scoring) can be as far outside of the desired cut line as the thickness of the material. The image below shows an inexpensive scoring tool (I think it cost ~$3)

Polishing the Edge of the Cut:
Depending on the quality of the cut and the desired end use, the edge may need to be polished. When using the acrylic as a window on a speaker enclosure or for an amp rack, you'll probably want to polish the edge. To make things easy, use a rubber or foam block and waterproof sandpaper. Since it will be nearly impossible to keep the edge perfectly square, I'll usually round it off. With a foam sanding block, start with rough paper (~180 grit). Wet sand with lots of water until the edge is uniform and relatively smooth. Then change to finer and finer paper until you get a satin finish with 600 grit paper (180, 360 and 600 grit will work fine). Remember to use lots of water.

Flame Polishing:
After the edge is polished to a satin finish, you may want to get it to a glass like finish. To do this, you can use a propane torch. Let me recommend that you practice on a scrap piece first. Using a propane torch, you very quickly pass the torch over the edge. You must move the torch very quickly. If you go too slowly, the acrylic will melt and boil. This will leave bubbles in the surface. This is from heating the acrylic too deeply. You only want to heat the very outermost edge/surface to its melting point. This will allow it to flow into a smooth glossy surface. As long as you're moving very quickly along the acrylic, you're not likely to cause bubbles (even if you're using the hottest part of the flame).

Practicing Flame Polishing:
The material that a CD is made of reacts similarly to that of the acrylic sheeting. If you want to scuff up a CD with some 600 grit paper (and water), you'll be able to remove most of the finer scratches and haze with the torch. Remember... Move VERY quickly along the surface. Allow the CD to cool between passes with the torch (just as you would when polishing acrylic). Don't you use a good CD. Try it with one that will not play. Heating the CD will cause it to cup slightly and it probably won't play anymore. This exercise is only to allow you too see how the process works. Two final suggestions... Don't burn yourself and don't burn your parent's house down.

Drilling Acrylic

Spiral Bit:
Standard spiral drill bits will not work well on acrylic. Their cutting angle is too aggressive which causes it to try to cut too quickly. This will lead to cracking and chipping around the hole. If you want to use a bit that can be used for metal also, try a bit like the one shown in the following photo. You can see that the main cutting edge is flat instead of angled like a normal bit. This causes the material to be cut in a more controlled fashion. If you don't want to spend the money on a new bit, you can grind a regular bit to the same profile.

Forstner Bit:
Forstner bits are very high quality bits that are generally used for woodworking. They make a very clean hole with little or no chipping. When used for drilling acrylic, you may need to use a cutting lubricant. I generally use a '3 in 1' type oil. Apply the oil to the cutting surface prior to drilling and to the drill bit shaft as you're moving through the material. If the bit is used dry, the friction between the sides of the bit and the material will cause the acrylic to melt (very bad). When used with lubricant, the hole will be very clean.

Standard Woodboring Bit:
Some people recommend against using woodboring bits but I've never had a problem with them. One advantage of the wood bit is the long centering point. This point will exit the other side of the material before the cutting edge. This allows you to turn the material over and drill from the other side. Since the cutting edge will not be pushing out as the bit cuts through surface of the material, there will be little or no chipping on either side of the material.

When using any of the different bits for drilling acrylic, you should:

Go slow. Do not force the bit to cut too quickly.
Use a drill press. This allows you to have much more control over the cutting speed and assures that you're drilling the hole perfectly perpendicular to the material. You should clamp small pieces down. If the bit grabs the material and spins it, it will cut you. Small pieces don't allow you to get a good enough grip to prevent the piece from spinning with the bit.
Practice on a piece of scrap material. If you crack a piece of acrylic after you've already polished the edges, you are not going to be happy.
If the acrylic melts as you drill through it (regardless of rate of rotation/feed), try using a light lubricating oil to reduce friction between the bit and the acrylic.

Fasteners:
When screwing a piece of acrylic down, you'll need to use some type of washer under the screw. Fiber, plastic and rubber washers will work. If you can't find those types of washers, standard metal flat washers will be better than nothing. If you use washers, you're less likely to crack the material if the screw doesn't go in prefectly straight. Predrilling the hole in the wood will help assure that the screw goes in straight. When tightening the screws, do not overtighten (especially when the surface under the acrylic is not hard). If there's a soft gasket under the acrylic, overtightening the screw will cause the material to crack. You should also use pan head screws (those with a flat mating surface under its head). Using bevel or bugle headed (drywall) screws will cause the acrylic to crack

Kicker ZX350.4 -- Clarity With Agressive Looks

2008-11-11T17:53:00.000-08:00

Kicker's impressive ZX350.4 amplifier.

Stillwater Designs, now better known as Kicker, is an "All American" company that's been around a long time. Back in the day, they originated the "kicker" box before anyone else even thought about it - that's probably why people still refer to them as "kicker" boxes. In the early 1990s the company started building amplifiers and has since quietly grown into a large force in the market. This time we take a look at the latest stage in the evolution of the Kicker amplifier, the ZX350.4.

Description
Kicker rates the 4-channel ZX350.4 amplifier at 60 watts per channel into 4 ohms, 90 watts into 2 ohms and 2 x 175 watts bridged into 4 ohms. The amplifier is an unregulated Class A/B design with both RCA and speaker-level inputs, and crossover and bass boost for each pair of channels. Visually, the amplifier retains its family resemblance to Kicker amps from the past several years. It has predominantly a textured black finish with a trio of rubber-capped knobs for each channel on the top plate. Swooping "V" contours in the top sheet metal frame the Kicker badge, and a red strip of silicon rubber lines the top plate on both sides.

The ZX series is an "upside-down" style amplifier. The main chassis is an aluminum extrusion that forms the bottom and sides of the amp. A cover plate made of stamped steel with the design and vents embossed in it covers the top of the amplifier. Adorning this piece are two badges (one for the logo and the other for the model number) and the control knobs for the gain, crossover and bass boost. The cover plate fits into two red silicone-rubber extrusions along each side of the heatsink. The molded plastic endcaps hold it in place.

The power/ground/remote terminal, two 20-amp fuses and the power/protect indicator light are all found on the left endcap, while the speaker connectors, RCA and hi-level inputs, fader and crossover switches are on the right endcap. Crossover frequency, gain controls and bass boost level controls are located toward the right-hand side of the cover plate.

The circuit layout inside is pretty much what you'd expect from looking at the outside. The power supply and the amplification/output section each occupy half of the main board, with an empty 1" strip running right down the middle as a buffer between them. There are other ways of controlling noise from the power supply, but it looks like isolation is important to the engineers at Kicker. The preamp section is nicely contained on a daughter board suspended above the output end of the main board. Both circuit boards are double-sided, but the preamp board uses mostly surface-mount parts while the main board uses all through-hole parts.

Starting with the power supply, power and ground is accepted through two large brass blocks. These two blocks will accept up to 4-gauge cable, although the manual recommends 8-gauge for this one as it is the smallest 4-channel in the series. B+ runs through a pair of 20-amp fuses and a small inductor. It then goes past three 2,200F capacitors for primary filtering and on to two pairs of high-speed, 49-amp switching Mosfets. A TL494 pwm controller drives the switching through the toroidal transformer at about 36kHz, achieving rails of + and - 30VDC. Secondary filtering consists of four 3,300F capacitors to stabilize the rails.

Jumping over to the input section, the first thing I noticed is that the signal grounds are extremely well isolated from the chassis ground. With 40k ohms of isolation, this amplifier will never participate in any ground loops in your system - that's for sure. The signal and shield conductors from the RCA are all fed into low-noise op-amps, thus making this a differential input. This style of input will better reject noise radiated into your RCA cables. The owner's manual reinforces this format by recommending twisted-pair cables rather than big fat coaxial RCAs. Differential inputs are typically found on more expensive amplifiers and have the potential for much better sound quality than less expensive designs. The gain control is accomplished through additional op-amps, rather than the cheaper (and noisier) style of attenuating the signal to ground.

Lastly, the output section consists of four complementary pairs of TIP35C/TIP36C output transistors, each capable of dissipating 125 watts, or 250 watts per output channel, which is more than adequate for this unit.

Performance
The amp performed well on the bench, meeting or exceeding every specification as listed in the owner's manual. The S/N ratio was a very respectable >94dB and the frequency response measured 13Hz to an astonishing 66kHz. The crossovers drifted ever so slightly from the published spec, but the difference was small and the curves were textbook. While filters are spec'd at 50Hz to 200Hz, the lowpass range was measured 54Hz to 203Hz, and the highpass was 45Hz to 180Hz. The bass boost was right on with the published 18dB boost, but centered at 41Hz rather than 40Hz. Trust me, you're not going to hear the difference on any of this.

The protection circuits worked well, both short-circuit and thermal. I like that they're self-resetting so you don't have to turn the system off and back on. On the bench the amp fired up smoothly and there was no turn-on or turn-off noise in the car at all.

Manual
The owner's manual really cuts to the chase. On page 2 there's a place to write down the purchase details; then it tells you how to mount the amp. Wiring is next, still on page 2, and then it slows down a little to cover different system configurations and the setting of controls. Page 5 covers troubleshooting and specifications, while pages 6 and 7 are the warranty covered in four different languages. Speaking of warranty, Kicker provides a 2-year deal when purchased from an authorized dealer. As always, keep your receipt.

Listening
The ZX350.4 was installed in the trunk of my Buick and initially connected to the front separates and the rear 6 x 9s. The crossovers were set for fullrange and the subwoofer was not hooked up.

I started out as always with Donald Fagen's Kamakiriad, which is a very well-mastered recording. There is a lot going on in all of these tracks, so it can really reveal any shortcomings with the amps and speakers. Track 1, "Trans-Island Skyway" starts out with a guitar riff, adding bass, keys and percussion as the intro builds. The bass line is pretty busy and can sound muddy, but the Kicker came through. Not only was the bass clean and clear, but everything else sounded distinct and well-balanced. The center image was a little fuzzy and quite low. I checked out "Tomorrow's Girls" for the highs. The cymbals in the intro were clear and smooth. "Snowbound" revealed good low-end clarity on the Fender Rhodes keyboard and bass guitar.

Tracks from Dada's Puzzle and Mary Chapin Carpenter's Come On, Come On reinforced my initial impressions that the response and clarity were excellent, but the image remained low and somewhat indistinct.

I returned to the trunk and changed the configuration. I kept the front separates connected but set the highpass to 100Hz. The other 2-channels were bridged and connected to the subwoofer with the lowpass set to the 100Hz. I repeated some earlier tracks with good results, and then went to "Posters" on the Dada CD. This one starts out with a great drum solo, adding electric guitar along the way. It sounded great, but didn't get as loud as I really like it. No foul here, it's just a smaller amplifier than I have permanently installed. In this configuration it should put out 60 watts each to the front speakers, and 175 watts to the subwoofer, where I normally have 100 watts to each corner and over 300 on the subwoofer.

Conclusion
I like this amplifier a lot because it did what it said it would do. The Kicker ZX350.4 is a very straightforward unit that is usable in several configurations. When auditioning the amp in my car I didn't feel the imaging and staging were as good as my reference amps, but I realize that it's not an issue for most people. However, clarity and frequency response were very impressive and that's something every consumer should be concerned with.

The ZX350.4 is stylish, somewhat aggressively so. At a retail price of $349, and a max power of 387 watts, it comes in at 90 cents per watt. As a general rule, anything with a retail price under a dollar per watt is not bad (for an amp below 500 watts). Overall it's a good amp at a reasonable price.

Hidden Lightweight Performance - Fiberglass enclosure construction

2008-11-05T20:22:00.000-08:00

Fiberglass enclosures have many benefits. Their ability to conform to unusual shapes allows you to maximize the enclosure volume in tight spaces. However there are trade-offs. Compared to MDF enclosures, fiberglass enclosures have a tendency to resonate. Also fiberglass construction requires significant preparation before you actually begin. It would be great if you could combine the benefits of a solid, easy-to-build MDF enclosure with the benefits of light-weight and unusual shapes of fiberglass enclosure. Now you can with the Dynamat fiberglass enclosure method.

The goal of this project was to build an enclosure that was completely hidden behind the factory side panel. Here is the step by step process.

Step 1: Build a frame work for the enclosure. The bottom and front panels of the enclosure are built using MDF. Save the cutouts of the front frame work for later in the build.

Step 2: Once the frame work is sized up, remove and use the front frame to trace the front baffle. Make sure to trace the inside as well as the outside

Step 3: Assemble the frame work. Notice that the cut out brace allows air flow while increasing the stiffness in the center of the enclosure.

Step 4: TacMat, placed behind the frame work, is used as the enclosure back wall. TacMat cushions and insulates the fiberglass from the vehicle, forming a non-resonant composite enclosure. This stops the squeaking noises common with fiberglass/metal contact. Once the TacMat is positioned, use a marker to trace the edges of the frame work.

Step 5: Working outside the vehicle, hot glue the TacMat to the frame. Trim to fit. Once completed, reinstall in the vehicle.

Step 6: Tape off and protect the area to fiberglass. TacMat does not require taping off the area behind. This is a great time saver. Notice how the TacMat is pulled above the frame. This will be trimmed off after the fiberglass is set.

Step 7: Fiberglass the enclosure. Make sure to pay special attention to sealing the front framework to the fiberglass and TacMat. The quality of the bond will determine the quality of the enclosure. For best results, use multiple small strips of fiberglass cloth. Build up the enclosure so that the fiberglass is approximately ¼” thick. Trim off the excess TacMat around the vehicle.

Step 8: Once the fiberglass is completely cured, remove the enclosure from the vehicle. For best results, wait 24 hours to remove the enclosure. This will ensure that the shape remains intact.

Step 9: Next apply DynaSpray (Dynamat’s liquid damping material) to the inside of the enclosure. This will further damp the fiberglass enclosure. The combination of TacMat and DynaSpray transforms the fiberglass into a non-resonant enclosure.

Step 10: Notches were placed in the front of the enclosure to clear mounting tabs for the factory panel. These holes are sealed with Kitty Hair (fiberglass strands suspended in body filler). Follow instructions on the product for best results.

Step 11: Taking the cut-outs from the front framework, adhere Dynamat Original by applying adhesive to the logo side of the product and the panels. For best results, use and upholstery grade adhesive. If you do not have access to that, you can substitute 3M Super 77.

Step 12: Remove the Dynamat Original release liner and apply to the front baffle. Use the guides you traced in Step 2 for alignment. The benefit of the double thick baffle with Dynamat Original is two fold. The thicker baffle provides an extra sturdy mounting for the woofer. By sandwiching Dynamat Original between the two MDF panels, the result is an internally damped front baffle that is extremely dead. Rapping on it with your knuckles sounds like concrete!

Here’s the look of the enclosure he so far.

Step 13: Tile DynaXorbs on the back wall of the enclosure. DynaXorbs are designed to absorb the back-wave noise and distortion of the subwoofer. The results are reduced internal enclosure reflections which enhance the sound quality of the subwoofer.

Step 14: Apply masking tape to the backside of the woofer mounting hole. This is a simply way to ensure that adhesive sprayed to the exterior of the enclosure does not get inside the enclosure. When mounting the front baffle to the enclosure, nails work fine but screws are preferred. Screws ensure a tight bond between the front baffle and enclosure.

Step 15: Cover the enclosure. Use your desired finish for your enclosure. I chose a simple trunk liner because my enclosure is hidden behind the factory side panel.

Using this construction method, I was able to construct a 1 cubic foot enclosure that hides behind the factory side panel. Resonances typical in fiberglass construction are non-existent. The enclosure is roughly half the weight as a comparable MDF enclosure. Not to mention that a enclosure this size would not have fit behind the factory panel.

This woofer is definitely heard but not seen. The JL Audio 8W7 (yes an 8 inch) is able to achieve a respectable 129dB when tuned for sound quality. With great low-frequency extension, the sound is effortless and the performance is much larger that the 8 inch woofer

Amplifier Power Ratings

2008-11-04T19:37:00.000-08:00

Extra features may also be built into a power amplifier. These features include built-in active crossovers, equalizers, signal processing and speaker level inputs. When shopping for an amplifier consider that all power ratings are not created equal. Some of the low-quality brands will exaggerate or even outright lie about the power output of their amplifiers. This is a good reason to stick with the well known manufacturers. The only true measure of an amplifier's power is its continuous power rating or R.M.S. rating. R.M.S. is an acronym for root mean square and refers to the amplifiers average power output. An even better method is the CEA 2006 standard but not all amplifiers adhere to this testing method. Basically the test is performed at 14.4 volts with a four ohm impedance load. The entire audible frequency range, 20-20kHz is tested with a distortion level of 1% T.H.D.

One thing to note is that doubling the amplifier power does not double the sound output. A doubling of system power adds only 3dB of SPL (volume) to the output. SPL works on a logarithmic scale so it takes 10dB of change for the sound to be "doubled". This works out to a little over three "doublings" of power. So if you have 100 watts of power you would need to double that 200 watts, double that to 400 watts and then double that to 800 watts. That would give you a 9dB increase. To truly get the 10dB increase you would need 1,000 watts or a ten fold increase in power.