Friday, February 23, 2007

Car Audio - "Tune" It UP

One of the best things you can do for your car audio system is to properly tune it. There are several variables to consider when doing this, and I am going to walk to through the most important ones so you will have a good understanding of how to get the most "bang" for the buck from you system.

Assuming you have an amplified system with one or more subwoofers, you can dial in your system to give you the best sound and have the durability you want from it. It starts at the head unit. You want a head unit with a good, strong output signal, between 4 and 5 volts on its pre-outs. Audiphiles tell us that 2-3 volts of good clean signal is good too, but that will require a little more amplifier power to get the decibels we're looking for. You also want a head unit with an adjustable subwoofer level. Start by tuning the stereo without the subs on. Add your bass and treble until you get the desired sound with minimal distortion at the loudest volume setting you will listen to it at. This is generally about 2/3 max volume. Once you are happy with the low/mid/high sound from the multirange speakers, we can add in the subs. If applicable, tune the sub outputs to about 2/3 maximum, and head to the amp. Start at the amp and adjust the frequency and the level to minimum, and turn the volume up to the the same loudest point we were working with earlier. Pull your frequency to about half way, and slowly adjust the power level upwards. If you hit the zone you want, stay there. Keep in mind, this is only a safe adjusting technique with a speaker system that matches the power output of the amplifier. If you want more from your system, incrementally adjust the frequency down slightly with the increases in power level. Your goal is to get a loud, clear bass from the subs that DOES NOT CLIP OUT under the loudest conditions you anticipate. If the amp clips out, then adjust the power level lower until it is back in the safe zone. Once the system is set where you want it, don't mess with it. Leave the levels on the head unit and the amp alone. The mistake I see with blown speakers and amps is trying to show them off with all the levels maxed out. This produces a lot of power at a high distortion level, which is damaging to the speakers and the amplifier. If you want a louder sound than what you have by tuning your system this way, it may be time to upgrade.

If you find you need help tuning your car audio system, contact Majestic Modifications by emailing
Brought to you by the sound experts at Majestic Modifications Auto Parts and Accessories.

Sunday, January 7, 2007

Car Audio

Car Audio Compontents
In the realm of car audio, the possibilities are endless. There are hundreds of brands and thousands of products out there. Majestic Modifications would like to help restore some order to the chaos of building your system. Lets look at some of the components that make up a car audio system.

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The Head Unit
The Head Unit is the brains of the operation. Without this component, your car audio system can't and won't work. The head unitis the central processing device in the system.

The head unit controls all the functions in your car audio system. Music too loud? Turn down the volume. Too soft? Turn it up. Want more bass? Add bass input. In addition to volume, bass, etc., the head unit may contain other systems within its casing. These include: tuner, cassette, equalizer, CD or amplifier.

You see, in a home music system, where you have much more room, many stereo setups will include a separate box for each one of these components -- CD, cassette, etc. You may have a home system like that yourself. In a car, with its space limitations, these components are often crammed into one box -- the head unit. This depends upon a number of factors, such as heat, space, cosmetic design and other concerns, and every car is different.

The Amplifier
All car audio systems have an amplifier, even if it's a small one. Occasionally the amplifier will be attached to the rear of the head unit; however, in most systems it is hidden elsewhere in the car to better dissipate heat.

Signal amplification is actually a two-stage process, handled by two separate components. These are the preamplifier and the power amplifier.

The preamplifier (preamp, for short) is a very tiny signal coming directly from the head unit. Whether it's reproducing a cassette signal, a CD signal, or an FM broadcast, the preamp puts out a signal that the amplifier can use. This is where the power amplifier takes over.

It's the power amp's job to take the signal from the preamp and boost it into the audible range. We'll cover this in more depth in our Amplifier column in this series. Again, because of heat, most amplifiers are located away from the head unit.

The Speakers
The speakers take the boosted signal from the power amp and create sound waves. Essentially, speakers transform electrical energy (the amplified signal) into mechanical energy (the motion of the speaker cone).

For now, know that all sound is vibration, which is a chain of frequencies in the air that eventually vibrate the membranes in your eardrums.

Sound energy is measured in wavelengths, known as hertz, with the audible range falling between 20 to 20,000 cycles. A cycle is the distance from the top of one wavelength to the top of the next.

There are three typse of speakers that produce sounds across the audible spectrum: woofers, tweeters and midrange drivers.

As the name implies, the woofer reproduces the lower frequencies. The tweeter, also aptly named, replicates the highest register. The midrange handles the frequencies in between.

Auxiliary Input Devices
Components such as CD changers and equalizers, not to mention cell phones, navigation systems, MP3 players and many of the newer technologies, interface with the head unit for amplification and signal processing.

We hope this helps you gather a basic understanding of car audio technology. Look for an in-depth view inside the head unit in our next column.