Rear speakers work but quiet...
Thread Starter
Advanced
Joined: Mar 2009
Posts: 60
Likes: 1
From: Memphis TN
Rear speakers work but quiet...
My '89 Convertible has had the original Bose radio changed out for a later 90's model GM Bose Gold Series CD player unit. I assume the speakers are original, though I guess they may have been changed out with the head unit.
The rear speakers work, but they are very quiet. I am no radio expert, but my guess would be that they are getting less "juice" than the fronts. Any suggestions where I should start looking?
Thanks
The rear speakers work, but they are very quiet. I am no radio expert, but my guess would be that they are getting less "juice" than the fronts. Any suggestions where I should start looking?
Thanks
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Some measurements need to be made to find out what is wrong. How much audio is being applied to the rear speaker amplifiers? Do the amps have 12v on them? If you supply adequite audio input level, do the amps put out the correct level and if not, then the amps need repair.
Thread Starter
Advanced
Joined: Mar 2009
Posts: 60
Likes: 1
From: Memphis TN
How do I measure all this? I know how to check for 12v but what about testing the levels?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
The input audio voltage is best tested with an audio voltmeter. You might have some success with the ac voltmeter in your VOM (voltmeter, ohmeter, milliammeter) test meter. You would still need to know what level is normal and the best way I know is to compare it to a radio that works ok.
Racer
Joined: Jul 2000
Posts: 345
Likes: 2
From: Arlington Wa
If the front speakers are OK take one out and connect it to the rear speaker, the connectors should be the same. This will tell you if the problem is with the speaker/amplifier assembly or the head unit. Your problem is most likely due to the amplifiers located in the rear speaker assemblies. It is a very common for the electrlytic capacitors on the amplifier PCB's to fail.
http://forums.corvetteforum.com/c4-t...-and-more.html
http://forums.corvetteforum.com/c4-t...-and-more.html
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Service Manual audio spec ('89) is about 1 volt a/c - it's the "about" part that makes a diagnosis difficult, but the fact that neither work would lead me to believe that the amps are the problem.
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Le Mans Master
Joined: May 1999
Posts: 6,520
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From: Windermere FL
Just to let you know, before I totally removed and replaced the Blose system I had the same complaint for my 90. The rears give mostly base and so are much "quieter" than the fronts. Seems to be the way the POS was designed. Was that way since it was new.
