Car Audio Installation Tips
This section will provide tips to help you complete and/or understand techniques in car audio installations - Updated Bi-Weekly
Choosing the Right AmplifierOne of the most common question asked by a newcomer to car audio is, "What is the best amplifier?". This question is just about impossible to answer. Choosing an amplifier can both be an easy yet daunting task. There are a few things to consider when choosing an amp.
The first question would be what kind of speakers will be used with the amplifiers?. In car audio, there are different speakers for different frequencies. High frequencies would be produced by tweeters, mid frequencies by mid range and low frequencies are handled by subwoofers.
Generally, tweeters and midrange can come in two styles. One is of the coaxial type, and the other is of the component type. The coaxial is a two-in-one speaker, with the tweeter within the larger cone. Components would have two separate speakers that come with a crossover (xover).
These two types need about 100watts RMS to produce clear sounds. Rule of thumb is: The higher the power, the cleaner the sound. These would only require amplifiers that are rated at roughly 100w @ 4ohms.
Unless you are about to enter competitions, there is no need to go higher. 100watts would almost certainly provide clean and loud sounds.
Subwoofers, on the other hand, require more power to push them to work. Low frequencies require more air to be moved, and that is why subwoofers are so large. A typical entry-level subwoofer might only require 200watts RMS, and the high power subwoofers can handle 1,000watts and beyond.
Amplifiers, especially subwoofer amplifiers, draw a certain amount of power from the cars alternator. A typical 100w amplifier will not draw a lot of power, but 600w amplifiers might draw over 50amps. There are a number of amplifiers that are in different class. The first is class A, with a high draw in power. A/B and B are more common types for low power (under 500w) amplifiers. Class D is the most common for amplifiers rated 600watts and higher. This is because their topology allows less draw while creating the same amount of power, as opposed to a Class A amplifier. Class D amplifiers make a significant amount of noise with high frequencies, so that would explain why it is only used in subwoofer applications.
For midrange and tweeter speakers, the connections are simple enough. Positive to positive, negative to negative. Majority of car audio speakers come in 4 ohms, and there is little to worry about in terms of load.
It is a different story with subwoofers, as subwoofers produce a mono signal. All amplifiers have the ability to be bridged, basically taking the two channels into one single mono channel.
Commonly, you would see (2channel) amplifiers with the following power ratings:
RMS @ 13.8v
100w X 2 @4ohms
200w X 2 @2ohms>
400W X 1 @4ohms
RMS denotes the continuous power that the amplifiers produce at 13.8volts. 13.8 volts is what car batteries commonly produce.
The first set of numbers mean that the amplifiers will produce 100watts to each channel with 4ohm speakers connected. Similarly, 200watts will be produced with 2 ohm speakers (usually two 4 ohm speakers on one channel). The last number is only relevant should the amplifier power subwoofers that handle 400watts RMS.
Take note that with a mono channel (x1), it is written as 4ohms again. Amplifiers have limited capabilities in ohms. The ohm level can make or break an amplifier. The lower the ohm figure, the more power amplifiers can produce. In the case of the amplifier mentioned above, only a 4ohm load can be accepted. You could connect it to a 2ohm load, but you would most probably overwork the amplifiers until they either shutdown or burn out. Unless the amplifier specifically states that it can drop lower, do not try to get more out of your amplifier.
Judging by the ohm loads, it is easy to see why it is rather hard to choose subwoofer amplifiers. The amplifier and the subwoofer have to compliment each other. For the above amplifier, a 4ohm single voicecoil (covered in Subwoofers) subwoofer with 400watt RMS handling would be ideal.
Do take note that well respected amplifier manufacturers underrate their amplifiers, whilst cheaper amplifiers would over rate their power to attract more people. Under rating amplifiers has been a common practice, so that during competitions, they can enter a slightly lower class for a little advantage.
This source is from caraudioresources.com - Patrick Buckley
WILL A CAPACITOR HELP ME?
If your lights dim with the beat, or your speakers start smoking without permission, or your CD skips a beat or two, your amplifier may be trying to use more fast energy than the electrical system can supply. Unfortunately, your car's electrical system is not thinking about the needs of your amplifier. Power is being robbed from your audio system by such trifling matters as: the engine and lights. This may leave your amplifier hungry for power, and worse, delivering destructive distortion when it fails to get it. Now, you should know that no capacitor is a substitute for an adequate amplifier to provide the amount of bass energy you want to project. Nor will it substitute for an inadequate car power supply. You may have to install a stronger alternator if you have a more powerful amp, or other equipment pulling your cars power.
INSTALLING A CAPACITOR
Some capacitors require you to pre-charge them to attain usability mode. To do this, you will need the charging board that comes with the unit. It is usually a simple PC board card with a positive and negative 16 gauge wires. Simply follow the included instructions, administering the power wire from a 12V source to your cap's positive terminal. Don't forget to ground it too. Now connect the card, positive-to-positive and negative-to-negative (or ground). When the indicator on the card comes on, the capacitor is fully pre-charged.
At this point, its time for the installation. Select a good spot, no more than 18" from the amplifier on the + power wire. Cut the power wire on the amp at the location where the cap is to go, and connect the wire to the positive terminal. If you are using ring terminals, install the first one flat on the base of the terminal. Then, run the second half of the spliced power wire from the same positive terminal (set the second ring right on top of the first one) and run it to the fuse block. If you are installing a model that uses a distribution block cap, simply hook the wire to the amp in the appropriate slot, and the 12V lead (to battery) in the appropriate slot. As always, follow the instructions.
Don't forget about the ground (-) connection! The cap should be grounded close by, preferably in the same spot the amp is grounded. Using the same gauge wire, run the ground cable to the negative terminal (usually the one not marked). Next, if your cap came with a remote lead terminal, run this to either the ACC fuse in your fuse block or to the REMOTE/ANT lead on your receiver using 16 gauge or so wiring. With the wiring all in place, secure the cap into place using an included bracket (if included) or using some 3" pipe brackets from Home Depot. You can install the cap right side up, upside down, side ways, diagonally, or whatever. Just make sure the vent at the top is never covered or blocked.
You can now proceed to safely reconnect your battery terminals. Sit back and enjoy cleaner, crisper and faster response, from your bass system.
This tip was provided by electronix warehouse.
STOP!!! THAT TRUNK RATTLE
First you have to identify what exactly is rattling.
the license plate frame is probably one of the most common culprits. Many license plates are only held on by 2 bolts instead of 4 and many license plates have ADVERTISING rings around them that could add to the rattle. You can usually put your finger on it and see if the rattling stops, if it does I put RTV silicone behind it and let it dry, then it wont rattle.
another common problem is air leaks passing through the trunk seal... to isolate this problem I usually lay towels along the trunk seal and close the trunk, if the noise stops then buy a new trunk seal, yours is worn out.
Sometimes the trunk lid surface vibrates on the trunk lid cross braces.
run a bead of silicone along the braces and in between the trunk
lid and brace if you can, let it dry and this should stop the
rattle.
Sometimes it is the car jack, or something in the trunk, wrap it
in a towel and stow it...
Now, no amount of dynamat is gonna fix your problem if you put the
dynamat where the rattle IS NOT! ... ;-)
First identify where the rattle is, then fix it...
Dynamat will deaden a panel, it is great for the overall acoustics of the car. I particularly like what it does to a metal door panel when you surround the speaker mounting hole with Dynamat Super. It can make a cheap car seem like your in a QUIET luxurious expensive car.
More Car Audio Installation Tips soon!!
This source is from TriniTuner and Electronixwarehouse
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SEALED ENCLOSURE - The sealed box is the simplest box of the three mentioned. It is simply a box with a driver in it. The air inside the box works as a suspension for the speaker. Depending on the size of the box different frequency responses can be achieved. This box is good for any music that demands tight, accurate bass. Expect flat response (not excessively boomy), deep bass extension, and excellent power handling. Since a sealed enclosure tends to require more power than a ported box, use an amplifier with ample wattage for optimum performance.
PORTED ENCLOSURE - The ported box is a little more complicated than the sealed box. In addition to using a determined amount of air to reproduce frequencies, they add a “port” that is a certain length and a certain area around. This port, usually a length of PVC pipe, is tuned to a certain frequency by variation in the two parameters of area and length. By adding this port, it reinforces low bass response. Some people prefer the sound of ported boxes for rock, heavy metal, or any hard-driving music. Ported boxes can deliver deeper bass than sealed boxes. You also get more output than you would from a sealed box at any given amplifier wattage. The rear wave of the cone motion is used to reinforce the front wave. When done properly the subwoofer system becomes more efficient than a comparable sealed enclosure above the port's tuning frequency.
BANDPASS ENCLOSURE - The purpose of the band pass system is increased efficiency over a small range of frequencies. This design also helps filter out unwanted midbass and upper frequencies. Bandpass boxes are a special type of ported box, because the woofer is mounted inside a dual-chambered box (one chamber sealed, the other ported), with the sound waves emerging from the ported side. The sound that comes out of the port is extra loud within a narrow frequency range. You will basically get a mono tone type of bass sound, which can become very boomy and muddy. Their aggressive sound is great for rap, reggae, and hard rock.
