Both Door Speakers Don't Work (Monsoon)
06-13-2018, 06:37 AM
#1
On The Tree
Thread Starter
Both Door Speakers Don't Work (Monsoon) Looking for help from those that are more stereo / electrically savvy than me.
I have a 97 Trans Am with the Monsoon system from factory (including the CD changer in the trunk, if that is relevant at all). When I got the car, the two lower door speakers (6.5" round on both LHS and RHS) did not put out any sound, but rest of the speakers (including door tweeters) did. However the head unit always acted wonky, volume controls didn't work properly, power kept cutting in and out, etc, so I didn't think too much of it.
Step 1 I replaced the stock head unit with a Pioneer MVH-S600BS unit and used the Metra 70-1858 wiring adapter. It all went smooth and works great, but still those 6.5" speakers in both doors aren't working, and the power still cuts in and out on the unit.
Step 2 I read the BCM tutorial on soldering bad joints, pulled out the BCM and saw the one joint was cracked, resoldered it and the stereo intermittent power loss issue is fixed. But still no door speakers.
Step 3 is where I decide both speakers must be blown (buddy with a Firebird says he's replaced both door speakers already), so I ordered a pair of Rockford Fosgate Prime R165X3. They are 4 ohm resistance, but other than a small volume drop from what I've read they should work fine. Also got the Metra 72-4568 speaker harness adapters so I couldn't screw it up. Just installed the driver's door speaker last night, and still no sound or activity whatsoever. Of course I wasn't smart enough to check anything with a meter when the door pad was off, so not sure if it's getting power or not, but my assumption is it's not since it's brand new out of the box and not working, with RHS speaker also not working.
So I'm at a bit of a loss on where to start with this. Looking at the pinout for the head unit, the LH and RH speakers have separate pinouts and wiring, so I can't see there being an issue with what I wired up. Also remember the speakers never worked with the stock head unit either. It's possible the RH speaker is blown and the LHS has some other separate wiring issue and they are unrelated, but I'm not holding my breath.
Sorry for the long read, but wanted to give all the details. Does anyone have any ideas on a source that might cause both door speakers, left and right, to go out together? All other speakers work, so it would have to be something that only affects those two. Any help is greatly appreciated!
I have a 97 Trans Am with the Monsoon system from factory (including the CD changer in the trunk, if that is relevant at all). When I got the car, the two lower door speakers (6.5" round on both LHS and RHS) did not put out any sound, but rest of the speakers (including door tweeters) did. However the head unit always acted wonky, volume controls didn't work properly, power kept cutting in and out, etc, so I didn't think too much of it.
Step 1 I replaced the stock head unit with a Pioneer MVH-S600BS unit and used the Metra 70-1858 wiring adapter. It all went smooth and works great, but still those 6.5" speakers in both doors aren't working, and the power still cuts in and out on the unit.
Step 2 I read the BCM tutorial on soldering bad joints, pulled out the BCM and saw the one joint was cracked, resoldered it and the stereo intermittent power loss issue is fixed. But still no door speakers.
Step 3 is where I decide both speakers must be blown (buddy with a Firebird says he's replaced both door speakers already), so I ordered a pair of Rockford Fosgate Prime R165X3. They are 4 ohm resistance, but other than a small volume drop from what I've read they should work fine. Also got the Metra 72-4568 speaker harness adapters so I couldn't screw it up. Just installed the driver's door speaker last night, and still no sound or activity whatsoever. Of course I wasn't smart enough to check anything with a meter when the door pad was off, so not sure if it's getting power or not, but my assumption is it's not since it's brand new out of the box and not working, with RHS speaker also not working.
So I'm at a bit of a loss on where to start with this. Looking at the pinout for the head unit, the LH and RH speakers have separate pinouts and wiring, so I can't see there being an issue with what I wired up. Also remember the speakers never worked with the stock head unit either. It's possible the RH speaker is blown and the LHS has some other separate wiring issue and they are unrelated, but I'm not holding my breath.
Sorry for the long read, but wanted to give all the details. Does anyone have any ideas on a source that might cause both door speakers, left and right, to go out together? All other speakers work, so it would have to be something that only affects those two. Any help is greatly appreciated!
06-13-2018, 07:55 AM
#2
The Firebird version of the Monsoon system has all tweeters powered directly by the head unit while all other speaker elements run off the amp. That means that the Monsoon amp (or its connections) would be a common point of failure for the front door mids while the tweeters were still working. You might want to check the amp connections and possibly even test continuity for the front speaker wires between the head unit and the amp as well as between the amp and the front speakers. Due to the length involved, the easy way to do that is to unplug the HU and the amp then put a jumper wire across the two left front speaker wires at the HU (short them together) then test for continuity at the amp connector across the same pair of wires. Repeat for the other side and for the amp-to-speaker wires on both sides. That will tell you if you have a wiring problem, If not, then the amp is the next most likely culprit.
06-13-2018, 08:51 AM
#3
On The Tree
Thread Starter
Thanks for the quick and detailed response, WhiteBird. I know the pinout for the head unit has separate wires for the LH and RH speakers, which I now know go to the amp, but do you know if the amp supplies power to the speakers from a single source? That would make a lot of sense.
In the interest of "easiness" I have a buddy with a 97 Firebird with the Monsoon system, so I might just borrow his amp and plug it in and see what happens to rule that out.
The other thing I noticed is that on the Crutchfield website where I ordered the speakers it says "To get full-range sound from your aftermarket speakers, you'll have to bypass the factory amplifier by splicing input and output wires together." But in the instructions I was sent by them there is no mention of this. Do you know which input and output wires they are referring to splicing together? And do you think it makes any sense that this could correct my issue?
Also since it's an aftermarket head unit putting out "normal" voltage to the speakers, is the amp even required any more? My understanding was that the factory head unit put out a low voltage to the amp which then powered the speakers, which if that is true couldn't I just connect each speaker directly to the head unit and bypass the amp altogether? Or am I misunderstanding how this system works?
In the interest of "easiness" I have a buddy with a 97 Firebird with the Monsoon system, so I might just borrow his amp and plug it in and see what happens to rule that out.
The other thing I noticed is that on the Crutchfield website where I ordered the speakers it says "To get full-range sound from your aftermarket speakers, you'll have to bypass the factory amplifier by splicing input and output wires together." But in the instructions I was sent by them there is no mention of this. Do you know which input and output wires they are referring to splicing together? And do you think it makes any sense that this could correct my issue?
Also since it's an aftermarket head unit putting out "normal" voltage to the speakers, is the amp even required any more? My understanding was that the factory head unit put out a low voltage to the amp which then powered the speakers, which if that is true couldn't I just connect each speaker directly to the head unit and bypass the amp altogether? Or am I misunderstanding how this system works?
06-13-2018, 03:26 PM
#4
The Monsoon amp takes speaker level input from a so-called Monsoon head unit which is nothing more than a standard Delco HU with an extra label on the front (in fact, many don't even have the label). That input is 4-channel. The amp filters and separates the signal and outputs eight channels to cover all the speakers except the tweeters (all speakers in a Camaro). The front left and right audio goes to the door speakers while the rear left and right go to the hatch area speakers. The sail panels have dual voice coil subs so they take two channels each of low-pass filtered signal that is generated from the other channels. Low frequency sound is not directional like the higher frequencies so the amp basically combines all of the bass audio from front and rear and passes it to the sail panels.
That's why Crutchfield says that you have to bypass the amp to get full-range sound in place of the low-pass filtered sound. That's true if you install ordinary coaxial speakers in the sail panels but if you have subs there (either original or replacements like CDT or Bazooka) then you'll want that filtering. The door mids already get a full-range signal from the amp so you don't want to change for that.
Unlike most aftermarket or even the factory Bose system used in some GM products, the Monsoon system doesn't use low-level (RCA) input. Using speaker-level input makes it very easy to swap head units. You could eliminate the amp and wire the HU directly to the speakers but then you have the filtering issue and why give up the extra power if you don't have to?
Trying your friend's Monsoon amp is an excellent way to test whether the problem is with your amp or somewhere else. If it turns out that the amp is the problem then you can buy a used one fairly cheap or you might consider bypassing at that point (although there would be rewiring and different speakers involved).
That's why Crutchfield says that you have to bypass the amp to get full-range sound in place of the low-pass filtered sound. That's true if you install ordinary coaxial speakers in the sail panels but if you have subs there (either original or replacements like CDT or Bazooka) then you'll want that filtering. The door mids already get a full-range signal from the amp so you don't want to change for that.
Unlike most aftermarket or even the factory Bose system used in some GM products, the Monsoon system doesn't use low-level (RCA) input. Using speaker-level input makes it very easy to swap head units. You could eliminate the amp and wire the HU directly to the speakers but then you have the filtering issue and why give up the extra power if you don't have to?
Trying your friend's Monsoon amp is an excellent way to test whether the problem is with your amp or somewhere else. If it turns out that the amp is the problem then you can buy a used one fairly cheap or you might consider bypassing at that point (although there would be rewiring and different speakers involved).
03-19-2021, 07:42 AM
#5
Hey I know this thread is pretty old but did you ever figure out a remedy for the problem? I am having this same issue with my 98 formula with monsoon. All speakers work fine expect the front door midranges. There is simply no power coming from the head unit to power the speakers. What I did was take the input wire from a rear speaker that was getting power and plugged it into the amp where the front door speaker input was and it worked great, but at the sacrifice of my rear speaker. I had the same issue with the volume going nuts and what not so I just ran a power wire straight to the amp, and that solved the issue, but I will definitely look into fixing the bcm. Thanks.
03-19-2021, 07:43 PM
#6
Fixing the BCM has nothing to do with the symptoms you describe. The cold solder fix is only to repair a solder joint in the retained accessory power (RAP) circuit which will cause the power to the radio and windows to cut out intermittently. If your radio is not shutting off completely on occasion then the BCM is not your problem.
In fact, it should be pretty obvious that you have a defective head unit (volume problems, individual output channels not working). What I don't understand is why you wouldn't spend a few bucks on a good used replacement head unit instead of hacking the wiring.
In fact, it should be pretty obvious that you have a defective head unit (volume problems, individual output channels not working). What I don't understand is why you wouldn't spend a few bucks on a good used replacement head unit instead of hacking the wiring.