Monsoon Stereo Problem, '02 Regal

Just bought this '02 Regal GS. It has the premium Monsoon Stereo system but the rear speakers barely have any sound coming out of them when I fade to the back. Front speakers sound great. Almost like the amp in the trunk is not working. Before I crawl in the trunk to poke and prod checking a fuse or other connections, hoping someone has experienced the same problem in the past. Maybe tell me what to check first and where to find it.

Thanks in advance.

Bob

Welcome to AF.

Checking the fuse to the Monsoon power amp sounds like a good starting point. Then check the 12 volt input at the amp electrical connector.

It's probably not a blown fuse since the front speakers are powered by the same factory amp as the rear speakers. A blown fuse for the amp would cause no sound at all. I would check the wiring between the amp & speakers and the wiring between the headunit and the amp. So you could say that you've already proven that the amp is getting power because the front speakers are working fine.

Are you just hearing the higher frequncies from the rear (no bass at all)? The rear woofers could be blown if that is the case. Albeit, it would be unlikely to have them both blow at the same time. You could temporarily hook up another speaker to the wires going to each woofer (NOT both sets at the same time though). If you get sound from the temporary speaker then the woofers are blown. If not then you know the problem is in the wiring.

Sorry so late to respond. I was out of town this weekend.

Actually rear sound seems to be just the opposite. I've got some low bass out off each speaker but no highs. I've also found that the original speakers were replaced with Memphis Car Audio M Class 6x9 coaxials, model 15-MC692. I've got some old Jensen 6x9's in the basement from my first car stereo 25 years ago (I never through anything away) that I'll have to hook up.

I did check the 15amp fuse for the amp and it's fine. These Memphis speakers also appear to have a special coil with a fuse for each speaker mounted in the rear deck. Those appeared to be fine as well. I think a call to Memphis Car Audio is in order next.

Not sure what the ohm rating is on the Memphis speakers but I seem to remember seeing somewhere that the Monsoon amp requires 2 ohm speakers rather than the typcial 4 ohm. And use of 4 ohm or higher speakers will eventually fry the amp.

The system sounds very nice as it is right now. I can't wait to hear it after I get the rear speakers working properly.

2 for rear and 4 front on monsoon speaker impedance.
Mozilla/5.0 (Linux; U; Android 2.1-update1; en-us; DROIDX Build/VZW) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Mobile Safari/530.17 480X854 motorola DROIDX

Sorry so late to respond. I was out of town this weekend.

Actually rear sound seems to be just the opposite. I've got some low bass out off each speaker but no highs. I've also found that the original speakers were replaced with Memphis Car Audio M Class 6x9 coaxials, model 15-MC692. I've got some old Jensen 6x9's in the basement from my first car stereo 25 years ago (I never through anything away) that I'll have to hook up.

I did check the 15amp fuse for the amp and it's fine. These Memphis speakers also appear to have a special coil with a fuse for each speaker mounted in the rear deck. Those appeared to be fine as well. I think a call to Memphis Car Audio is in order next.

Not sure what the ohm rating is on the Memphis speakers but I seem to remember seeing somewhere that the Monsoon amp requires 2 ohm speakers rather than the typcial 4 ohm. And use of 4 ohm or higher speakers will eventually fry the amp.

The system sounds very nice as it is right now. I can't wait to hear it after I get the rear speakers working properly.

The pictures of the Memphis 15-MC692 speakers show that they have two sets of terminals. This is exactly what you need to correctly hook them up to the Monsoon amp.

I doubt that four ohm speakers will ruin the factory amp if they are hooked up correctly. Somebody probably thinks this because they incorrectly hooked up regular coaxial speakers. Using regular coaxial speakers is possible, but only if they have separate wires going to the tweeters. I have successfully installed a set of Alpine Type-R 6X9 coaxial speakers into the rear of my brother's 2001 Grand Am w/Monsoon. They have been working great for over two years. The trick is hooking up the woofers and tweeters separately. The Alpine speakers I used only have one set of terminals, but they have separate wires going from those terminals going to the tweeter.

The factory speakers are what's called "Bi-Amped". This simply means that the woofer and tweeter are amplified separately so they each have their own wires going to them.

I'm thinking that coil you are seeing for each speaker is most likely a crossover. You don't need it though since the Monsoon amp already puts out two sets of signals for each speaker location. One is set provides a signal for the woofer and the other set for the tweeter. You cannot simply combine these connections though. They need to remain isolated from each other otherwise your amp will be damaged.

I think your best bet is to start wiring from scratch. As previous mentioned, your Memphis speakers have two sets of terminals. One set is for the woofer, the other is for the tweeter. The tweeter terminals have red (+) and black (-) wires attached to them that are routed into the back of the woofer magnet where they go down the center of the magnet to get to the tweeter.

Here is the color scheme of the wiring for your factory speakers:

Left Rear:
tweeter (-) YEL
tweeter (+) BRN
woofer (-) LT GRN/BLK
woofer (+) DK BLU/WHT

Right Rear:
tweeter (-) LT BLU
tweeter (+) DK BLU
woofer (-) LT BLU/BLK
woofer (+) DK GRN

Now just correctly hook these wires directly up your Memphis speakers in the respective places and you should be golden.

Well, I finally got a chance to do some trouble shooting.

I took one of those old Jensen 6x9's and hooked the LW and HW wires for the Memphis speakers up separately to the Jensen speaker with the stereo running with fader and balance towards that speaker. I had a little more sound through the Jensen but not much at all.

Next, I grabbed an old Kenwood home stereo receiver/amp and brought it out to the garage. I hooked up the Jensen speaker to it and it sounded fine. I disconnected the wire and climbed in the trunk and touched the pair up to the woofer input on the Memphis speaker and WOW, now I know the kind of base that speaker can produce. I touched the wire up to the tweeter or high speaker tabs and got good highs. Therefore, I'm assuming it's the amp. However, the crossover????

Funny you should mention that because while digging through the old speakers, I came across an old 3-way crossover I have. And the little 1.5"x2" boxes in the trunk have coils in them like you'd expect a crossover to have. I wonder if the crossover is connected wrong or is over filtering the signal?

Looks like the factory plug is still on the speaker wires that come from the amp and if I put factory speakers back in, I could just plug things back together. Looks like the Memphis audio installer (or the car's owner) attached a plug to the factory connector and ran the wires to the crossover then out of the crossover with the 4 wires to each speaker, one set on each side.

I am getting some sound out of the speakers but maybe 10% of what it should be. So is the amp really blown??? I suppose the next step I'll take is to disconnect the factory plug, grab a couple of wires with aligator clips and jumper from the factory plug directly to the Memphis speakers, bypassing the crossover. If I've got the same low audio level, it's got to be the amp.

Thanks for identifying the color codes of the wires for me so I can go jumper from the plug to the speakers.

Back to the trunk.

It seems to me that whoever installed the new speakers knew what they were doing, at least they thought they did before they came across four wires for each side instead of two. So at that point they probably just kept connecting two different wires to the crossover until they got "acceptable" sound without doing any reasearch to figure out what the color scheme of the wiring was. They just ignored the other two wires because they were getting sound so they thought everything was fine.

If all four of the factory speaker leads are going to the crossover, it is causing a short. So be sure to split them up and keep them separated. If only two wires were going to the crossover (from the factory speaker leads), then the crossover was only receiving half the signal at best. That's assuming that the correct pair of wires for the low or high frequency signal was hooked up correctly (I'm referring to polarity or +/-) to begin with.

Like I said earlier, leave the crossovers out. They are not needed since the amp provides discrete signal for the woofer and tweeter on both sides. Just hook all four factory speaker leads (from each side) directly to the respective places on the Memphis speakers on each side and you should be rockin out to some great sound.

The low frequency wire goes directly from the factory plug to the low side of each of the speakers. The high frequency goes into the crossover and out to the high side of the speaker on each side. The odd thing is that another pair of wires comes out of the crossover on each side and goes up into the rear deck somewhere. I've got no clue where they go. I've got to get ahold of Memphis Audio and see if I can get the install info on these speakers. Like you suggested, I'll probably just bypass the crossovers unless there's something in the Memphis manuals that convince me otherwise.

Thanks.

Bob

The low frequency wire goes directly from the factory plug to the low side of each of the speakers. The high frequency goes into the crossover and out to the high side of the speaker on each side. The odd thing is that another pair of wires comes out of the crossover on each side and goes up into the rear deck somewhere. I've got no clue where they go. I've got to get ahold of Memphis Audio and see if I can get the install info on these speakers. Like you suggested, I'll probably just bypass the crossovers unless there's something in the Memphis manuals that convince me otherwise.

Thanks.

Bob

I can't be sure, but an educated guess is that the extra pair of wires is just going to the factory rear tweeters which the installer just left in there and hooked up too. The terminals on the crossovers should be labeled. Check and see what the wires are hooked up to.

You can try to contact Memphis Audio, but I don't think they will be much help and may even tell you that you cannot hook them up to the factory Monsoon amp - which is only correct if you want to use the crossovers.