For 1990-2009 cars

#### Tools Required

J 39916-A Audio System Diagnostic Kit

Important: Always compare speakers front-to-front and rear-to-rear. Do NOT compare front speakers to rear speakers, because of the following reasons:

• | The speakers could be of different types

• | The mounting environments could cause the speakers to sound differently

Use the following basic tones in order to test, and evaluate the coaxial speakers and any other complex speaker systems:

• | 50-Hz tone

• | 500-Hz warble tone

• | 9-kHz spectral tone

#### Bass Test which is a 50-Hz Tone

Use the 50-Hz tone in order to evaluate the bass response of an audio system. The tone also helps in evaluating audio systems which have separate subwoofer amplifiers and speakers.

#### Midrange Speaker Test which is a 500-Hz Warble Tone

Use the 500-Hz warble tone in order to evaluate the midrange speaker response. This tone is called a warble tone because the tone produces a warble sound.

#### Tweeter Test which is a 9-kHz Spectral Tone

Use the 9-kHz spectral tone in order to evaluate the tweeter, or the high frequency. This tone is a section of frequencies of equal amplitudes that range from 8.5-9.5 kHz. The tone sounds like chirping crickets.

#### All Speaker Test

The combination tone is used for numerous audio problems, such as distorted sound, or such as loss of sound. Use the combination tone in order to perform the following steps:

1. Set the fade control and the balance control in the detent position
2. Make the same AC voltage measurements on the speaker terminals

With these voltage measurements, you can diagnose a speaker or an amplifier.

#### Speaker Buzz and Rattle Test which is Swept Sine from 50-Hz to 8-kHz

Use the next portion of the diagnostic tape in order to diagnose rattles that come from the speaker or from the grille. The first test consists of 2 tones which are played back-to-back. The second test consists of a variable frequency tone, but the frequency change is at a much slower rate. Use both tests in order to repair a rattle or a buzz that come from the speaker. After you have isolated the noise problem, perform the following steps:

1. Set the fade controls and the balance controls to the correct locations
2. Play the test tones in the specific problem area