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My rear speakers are very quiet!

Well I finally got around to registering at the website of my favorite radio show on Saturdays :stuck_out_tongue:

Having just turned sixteen and getting my license, my parents thought it would be a nice reward to buy me a car to travel to and from their errands.

So we looked around and we finally got an amazing deal. We got a 2002 Buick Century Special Edition with 15K miles and 20 MPG City and 30 MPG Highway, as well as all the nice electronic gadgets like audio controls on the steering wheel and cruise control; all for only $9,500 including all the fees! It had come in the day we went to the Wallace dealership and it was clean as a whistle without the dealer having cleaned it yet!

Now my question has to do with the audio system. The car comes with a 6-speaker “Concert Sound II” audio system. I was very excited to see the 2 large speakers behind the rear passenger on below the back windshield.

But I noticed that although the sound is nice and crisp, it lacks some bass, and that not much sound was coming from behind me. So I turn the fade knob so only sound from the rear speakers would be played, only to find that just a small amount of treble was coming out.

I turned down the treble knob and turned up the bass knob and I heard nothing. I turned up the treble knob and heard the same very low but audible sound that was coming from it.

I looked at the speakers from inside the trunk, and they seem like they are large sub-woofers.

I am truly perplexed as to why such large speakers sound like a pair of headphones cupped in your hands!

Is this normal, or am I having some kind of trouble here?

Any help is appreciated :slight_smile: Thanks,


Are you sure they are sub woofers? I would be surprised if there were two large subwoofers mounted in a Buick Century in the area below the rear window.

Two possibilities come to mind…either they are midrange speakers that have blown, or the audio settings are set to a “front seat” bias. That is, the audio system is not sending much to the rear speakers but focusing on the front speakers only. Cadillac Bose systems have this setting, check your audio system to make sure that’s not the case, before replacing speakers.

Let us know how it goes, and congrats on the new car.

Well, they look as if they were sub-woofers but I could (probably :P) am wrong.

But that’s good insight. However even if they do have the front speaker bias, why wouldn’t the rear speakers emit any bass at all?

And thanks, she rides so smooth and got me from Ft. Pierce, FL to Orlando, FL on $15 of gas. I love the car!

Sounds to me like the rear amplifier is not working. This may be part of the radio itself, or a separate amp. I am not familiar with that particular car or sound system, but as a first pass check all the fuses. If there is a separate rear amplifier it may have its own fuse. If the rear speakers have on-board amps, again there could be just a blown fuse somewhere.

One other quick test, if you have a spare speaker around that is known good, you can hook it up to the wires for one of those rear speakers to see what sort of sound comes out. That won’t work if the rear speakers are the type with their own on-board amps, though.

Well I’m currently trying to figure out how to open the damn fuse box.

It won’t open easily, and I don’t want it to break. I’m not sure what has to be done, but simply pulling it isn’t doing the trick.

I’m going to agree that is sounds like the rear amp isn’t working. The little sound you’re hearing is the bleed through from the pre-amp.

As for them being a woofer. They could be. But you’ll have to look at the front of the speaker to tell. I don’t think it’s a mid-range speaker. Where’s the hi-range and low to go along with it??? Unlikely that someone would mount a mid-range speaker. Could be a FULL range speaker.

As for the it not being a woofer because of it’s size…well it could very well be. I’ve seen woofers that were only 6". Didn’t make a GOOD woofer…but it was a woofer. Could only go down to about 100hz. A decent 8" can easily go to 70hz.

Well I got the fuse panel open after a not so graceful tug, and all the fuses for sound seem to be in check.

Here is a picture I took.

I hope it helps somewhat.

I’m still within the 30 days warranty, so should I ask the dealer?

So what can I do to fix this?


Since you say it’s under warranty…how about taking it back to the dealer and have them look at it.

If there is a warranty, I’d try that route first.

After that, try hooking up a known good speaker (from the picture you’ve got normal speakers, not anything fancy). If that doesn’t work any better you probably are looking at replacing the head unit. If there is a separate rear amp, that would be the likely problem, but I don’t know if you would have that or not.

The speakers look like a standard 6x9 Coaxial or tri-axial speaker.

Well, I took it to the dealer today, only to be told that the speakers are not under warranty-- only mechanical parts-- which I think is BS.

I went to Sound Advice and the guy there told me something was definitely wrong and that it is either the radio is bad, or the amplifier is bad. He looked around in the trunk and couldn’t find it.

Any idea where I can find the amplifier?

It is probably in the radio. Most stock car stereo systems don’t have external amplifiers, some do, but mostly not. Check with Crutchfield and see what replacement radios are available. You can call them and they will know if your stock system has an external amp. They have very good information on this sort of thing, and provide instructions on how to install a replacement if you buy from them. Did he try a known good speaker? It’s a real simple test.

I’m not surprised about the warranty. Even new cars often have a separate warranty for the radio that is less than for the car itself. Used warranties generally only cover basics.

No he didn’t he told me to try that on my own.

I tried Crutchfield, and they said they only help customers, so I’m out of gas there.

EDIT: Actually, I was able to get them to tell me that there are no external amplifiers. So the problem must either be in the radio or the speakers.

There you go. For less than $100 you can replace the radio, and for $20 more you can replace the speakers. It’s most likely the radio, though.

Wow, this really helped a lot!


I think I’ve got this solved now, thanks.

The amplifier is in the radio if there is no external one.

A receiver is made up of 3-5 different components.

. Pre-amp: Switches between sources and feeds the amp the appropriate signal.
. Amp: This unit supplies the watts to the speakers. Takes the signal from the pre-amp and amplifies it.

Sources components:
. Tuner: FM or AM or both…Or satellite or Digital.
. Cassette: plays cassettes.
. CD/DVD: Plays CD’s or DVD’s.

ALL sound systems have a pre-amp and amp. And you need at least ONE source component. Some have 3.

A receiver has a Tuner/Pre-amp/Amp all built into one chassis. They may share internal parts like power. A integrated amp is a Pre-amp/Amp combo. And then there’s separates where each component is in it’s own chassis. MOST car audio systems are receivers. Some have external amps. You usually get better sound quality with separates (although not always).

So the problem sounds like it’s in the amp section. These can either be separate or integrated. I guess you may have found the answer to that then. So if you have a receiver and one of the components in that receiver is bad, then you have to replace/repair the receiver. And as I stated before I think you’d be far better off just buying a new one. The ONLY thing you’ll be compromising is the OEM look. Although I bet you can get real close.

A look at the 2002 Buick Century wiring diagram, which is available through my local public library online Web link ARRC (Automotive Research and Repair Center), shows all the wiring for the sound system. If the rear speakers have two wires, they are full-range speakers and DON’T have a separate amplifier. All of these speakers use the head-unit’s built-in amplifier.
If the rear speakers had 4 wires, each, they would be on a separate amplifier. These rear speakers are mid-range/ bass units…no treble.
You could go to the salvage yard for a Buick which has the separate amplifier and the mid/bass speakers; then, use the wiring diagram to wire it up.

Did you figure out if the problem was your head unit? I have the exact same problem in my 2000 Buick Century, although this car is certainly a lot older (180,000 miles). I thought that the rear speakers only worked properly when it is hot outside (they are definitely subwoofers and sound pretty good when they work), but I just found out that they work when it is cold outside, just very quietly and shrill, when I set the focus to the rear and crank up the volume. So it isn’t a broken voice coil I think. (unless it is a broken voice coil - now that I think about it, a lack of power shouldn’t cause the audio to be so shrill) The replacement speakers are a lot cheaper than the head unit, so I hope that’s the issue.