Tuning Your System Audio Car

In This Chapter

► Setting amplifier gain

► Using a real-time analyzer 

► Looking for trouble spots 

► Avoiding annoying noise problems

So you’ve installed the car audio system of your dreams. You’ve spent months saving up for it, weeks designing and planning the system, and many days and nights installing it. Then comes that moment when you finally turn the key, hit the power button, crank it up, and ... it sounds terrible.

How could that be? You spent good money for the best components, you installed everything properly, but it still sounds less than stellar.

Tuning In: Getting the Best Sound Out of Your System

A car audio system is like a musical string instrument: If it’s well designed and properly constructed, it has the potential to create great music. But like a string instrument, it first has to be tuned. With an instrument such as a guitar, it’s a matter of stretching or loosening the strings to get it in tune. With a car audio system, tuning means properly matching the signals between the various components, making sure the bass doesn’t drown out the treble, and fixing any annoying noise problems. And as with a musical instrument, it takes a good ear to tune a car audio system.

In fact, using measuring devices such as a real-time analyzer to tune a car audio system can be very helpful, but the final judge should be your own ears. For example, you want to strive for a flat frequency response, meaning that the system produces an equal amount of sound at all frequencies — not too much bass and not too much treble. But remember, you also want it to sound good to your ears. 

Understanding What constitutes good sound

Before you can get the best sound out of your system, you need to know what to listen for. 1 cover this in more detail in Chapter 3, but here are some of the basic elements of sound quality:

The basic elements of sound quality are

Smooth frequency response: The ability of a system to reproduce the I audible frequency spectrum without emphasizing or deemphasizing one particular frequency range.

Clarity: The ability of a system to produce music without distortion and other noise.

Dynamic range: The ability of a system to reproduce loud and soft pas¬sages in music, and at loud and soft volumes, with the same level of detail.

Tonal accuracy: The ability of a system to faithfully recreate the sound of the instruments, voices, or ambiance in a recording.

Staging and imaging: The ability of a system to recreate the illusion of a stage on which a performance is occurring, in which you should be able to pinpoint the sonic image of each individual performer and instrument on the stage.

Points of reference

Although you may be able to understand all of these concepts in theory, you need to hear them in practice. You need a reference. You need to find the best system possible and listen to it so you know what good sound is and how to apply to your own system the sound quality concepts discussed above.

Visit a local car audio shop and ask to hear one of their best-sounding demo vehicles, or go to a sound-off and listen to some of the award-winning SQ or sound quality vehicles there.

To get the best possible reference, visit a high-end home stereo store and listen to one of their systems with well-recorded music. A car audio shop or home audio store will likely have some sound quality (SQ) recordings on hand. Make of note of what they are, or bring some of your own CDs that feature well-recorded music or just your favorite music. 

Setting Gains

The first thing you’ll want to do when tuning a car audio system is set the gain or input sensitivity of each component, which is also called level matching. Gain is the ability of a system to increase the amplitude or power of an audio signal; it is measured in volts. A good way to grasp this concept is to think of an amplifier as simply a large gain device: It takes an audio signal and increases its gain. A volume knob on a head unit also acts as a gain control.

Because a car audio system is made up of various components, with varying levels of input and output voltage, what you’re trying to do when you set gains is dial in each component for maximum signal level with the least amount of noise — in other words, achieve the highest signal-to-noise ratio possible. Every component has a maximum amount of gain or signal level it can produce before it starts to clip or distort the audio signal, and each component has an inherent noise floor, which is a measure of the noise the component itself produces or picks up from other sources. In a perfect world, a component would produce zero noise, but car audio (and even home audio) components are far from perfect, and the car environment, with all of its potential to induce noise in a system, is very imperfect.