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 or other complex speaker systems:

• | 50 Hz sine tone

• | 500 Hz warble tone

• | 9 kHz spectral tone

#### Bass Test (50 Hz Sine Tone)

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

#### Midrange Speaker Test (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 (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 ranging 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 no sound, coming from the speakers. When using the combination tone, perform the following steps:

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

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

#### Speaker Buzz and Rattle Test (50 Hz-8 kHz Swept Sine)

Use the next portion of the diagnostic tape in order to diagnose rattles coming from the speaker or from the grille. The first test consists of 2 tones 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 coming from the speaker. When you have isolated the noise problem, perform the following steps:

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