Speaker/Amplifier Diagnostics

Always compare the front speakers to front, and rear speakers to rear. Don't compare front speaker to rear speaker because they could be different speakers or their mounting environment could cause them to sound different.

The three basic tones used to test and evaluate coaxial speakers, or other complex speaker systems are a 5 (1 Hz sine tone, 500 Hz warble tone, a 9k Hz spectral tone. The combination tone is a blend of the above three tones.

BASS SPEAKER TEST

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

MIDRANGE SPEAKER TEST

The 500 Hz warble tone is used for the evaluation of midrange speaker response. This tone is qualified as a warble tone because it has different audio characteristics than a sine tone. This tone produces a warble sound. At these midrange frequencies, it is better to use a warble tone than a sine wave because the location of warble tone source, such as a speaker, is easier to identify. A normal sine tone can set up a standing wave within a vehicle which can make it difficult to determine it's source location.

TWEETER TEST

The 8.5k Hz - 9.5k Hz spectral tone is used for tweeter or high frequency evaluation. This tune is a section of frequencies of equal amplitudes ranging from 8.5k Hz - 9.5k Hz. This sounds like a group of crickets chirping. This type of tone is used for two reasons One, much like the warble tone, it is easy to locate it's source, and two, this type of tone is easier to identify for those people with high end hearing loss problems.

ALL SPEAKER TEST

The combination tone can be used in section of tape and can be used for numerous audio problems such as distorted or no sound from speaker or speakers. When using the combination tone, comparative AC voltage measurements can be made on the speaker terminals, provided the fade and balance controls are in the detent position. With these voltage measurements, a determination can be made in the diagnosis of speaker or amplifier.

SPEAKER AND GRILL RATTLE DIAGNOSTICS

The next portion of the tape can be used to diagnose speaker and grill rattles. If the problem has already been isolated, the fade and balance controls can be set to the proper location and the test tones can be played in the specific problem area.