justinsrx7

The other day, the bose sub-woofer in my 3rd gen started making noises like the actual speaker was torn. I have not taken it apart yet, but I assume I will need to replace the speaker in the wave box.

Do you know if I can get a replacement for this or if there is an aftermarket replacement product that will perform better in the wave box than the bose speaker?

Thanks,
Justin

mrhetrick

iTrader: (18)

Justin! I feel your pain. I too have what sounds to be a blown speaker in the rear wave unit. I was going to take it to an authorized Bose tech., but that is sure to cost a ton. I had thought about getting one or maybe two of those Bazooka tubes. Not sure if they are compatible, but if they are that might be an option. Let me know how things turn out.

Mike

justinsrx7

Actually, in reading more threads today, it sounds like it is not a speaker that is blown at all, but a failing sub-woofer amp. Now I am trying to find out where that amp is located in the car and where I can get a replacement.

I love the sound of my car engine and exhaust note, so I don't need a killer stereo to drown that out. I just want background music without the blown speaker sound.

Dane

Most of the time the actual issue is the amplifiers - not the speakers themselves. The failing of the amps will replicate a bad speaker almost perfectly until it finally dies.
The Wave is somewhat of a bandpass design, so you will probably not hear the "squealing" that you normally associate with dying Bose amps, but this noise is the last stage of the Bose amp(s) going out before the go totally mute.
Either way, it is a very simple affair to test the Wave. Look for the test plug on the left side (if facing from the rear of the car). It has two pins and is probably buried underneath. Simply put speaker output from a home stereo or similar to this and see how it then sounds (this harness patches the output directly to the speakers).
If it sounds decent at this point, you likely have a bad amplifier or both (there are two located on the bottom of the assembly).
Either way, just for good measure you can completely pull the Wave from the car which only takes a few minutes. Then take it apart and inspect the speakers inside and individually test them hooked to a home stereo.
If for some reason you find that a speaker or speakers is bad, you can obviously replace them if you can find a set used (or buy new). Some other Bose equipped cars use a slightly different version of the Bose 6.75" driver that will interchange with a little fabrication (ie 90 300ZX rear, 92 Legend, etc). I have used the alternative drivers in the past for customers that wanted to save $$, but really wouldn't recommend this technique for a DIY'er because the speakers are mounted in an isobaric way, and the slightest leak or misalignment would totally destroy the sound quality.
If you determine that it has bad amplifiers then you have a few options at this point. The most obvious one is to replace the amplifiers, but you must use some from a Wave - the crossover points and gain parameters are different for every Bose OEM amp based on mounting location and vehicle.
The second option would be to add aftermarket amplification using a deidcated sub amp that is a natural 1 channel version (not bridged due to low impedence load). Obviously this could get potentially messy, particuarly if you are running the factory head.
Finally, if you actually determine that you will need replacement parts, your easiest bet would probably be to buy a complete Wave from Ebay and make one good one from the two you would then have (90% of them sold on Ebay are bad in some way - why are they selling it?).
Normally I stock used parts for the Wave, but due to the spring rush I am pretty much tapped out. However, if you need amps tested or anything on these lines, I would not charge you anything for that - you would only be looking at shipping in both directions.
Either way, if you need any more info or help - email me.

DANE
zmaxsystems

CCarlisi

I am using an aftermarket amp with my Bose sub and it sounds great-better than with the factory amp. If you want a replacement amp I believe I have one in my parts car. Shoot me a PM if you're interested . . .

Rotornut

Did you say that an aftermarket amp works with bose wave? I did not know that this is possible. Did you just remove the bose amp and connected the speaker wires to the aftermarket amp?

Thanks.

finnicky7

I have a full Bose trunk system if anyone wants it PM with an offer.

CCarlisi

-Yes. Remember the speakers are setup isoberically (sp?), so connect the wires accordingly. Also I believe the Sub speakers are 2ohms rather than 4ohms which may be an issue depending on what amp you're using.

Dane

Uhh, didn't you read where I said that a couple posts before his? I guess I wrote all of that for nothing?

Rotornut

Sorry Dane, I was browsing through my lunch time earlier and I didn't get to the part where you mentioned what you did to the wave setup.

pinkrx7

iTrader: (2)

Anyone find a 1ohm 6 inch replacement woofer that works well in the wave system?

davesan1

iTrader: (4)

Dane -

You seem well versed in FD speakers, so I would really appreciate your help on the following situation:

My rear Bose speakers suddenly started to make a very loud low frequency hum. The head unit volume control has no effect on it. The front and side speakers are working OK. The rear Bose units have no head-unit-based sound - just the loud hum. The hum is coming from both of the speakers.

OK then, my diagnosis would be that the inputs to the rear amps are open circuit and I just have the normal situation found with any o/c input on any amp. So one would think that the plug that supplies the inputs to the rear amp(s) has simply fallen out of the amp. socket. The schematic confirms that the same plug is used for both amps. Great-diagnosis seems good so far. However, also according to the schematic, the power to the rear amps uses the same plug as the inputs! The power is clearly getting to the rear amps (i.e. loud hum!) so, unless the connector is slightly out of its socket and the power pins are longer than input pins, (possible but unlikely), my diagnosis doesn't fit.


The same situation exists if I assume it is the head unit plug for the rear amps that has fallen out. However, once again, the output pins and the power for the rear amps share the same plug at the head unit. So I'm stumped.

It seems unlikely that both rear amps went bad together. It also seems unlikely that both head outputs to the rear amps went bad together. However, those are the only two possibilities left (I think).

So, now to my questions;
1) Any other possibilities that could be causing the problem?
2) Where exactly are the rear amps located? Inside the "Bose tubes?" In a separate box somewhere?
3) What do I have to remove to get to the rear amps?

Also would appreciate help from anyone else. Has anyone had this exact same problem?

Thanks

Dave

davesan1

iTrader: (4)

OK, I pulled the rear speaker assembly out of the car and diagnosed the problem to one of the amps. being bad. Anyone have one for sale? (I have also posted this request on the parts for sale/wanted forum). I also seem to remember reading somewhere that new (Bose) ones were available for around $60, but I can't locate the thread I saw it on. Anybody know anything about this option?

BTW, my comment in my earlier email that "it seems unlikely that both amps. failed at the same time" is now explained. In fact only one amp. had failed, but, because of the construction of the "Tube" enclosure you can still hear the output, (loud hum in this case), from both left and right sides when only one amp. is working. The hum was so loud from the bad amp, (regardless of head unit volume control setting), that it totally blanked out the other amplifier+speaker sound, which was working just fine. I'm temporally running on just one amp, with sound coming out of both sides, albeit of slightly lower quality.

davesan1

iTrader: (4)

MattGold -

I sent you a reply to your Private message. In the interests of the general forum, I'm also pasting it here, as below:-
MATTGOLD MESSAGE:
Hey Danesan,
I am having an identical problem as you described here:
https://www.rx7club.com/showthread.p...bose+diagnosis
'low frequency, LOUD hum from the rear speakers'
However, in my case, I have NO sound from anything else.
What did you end up doing to solve your problem? Did you buy a used unit - if so, what did you need to replace? The entire 'snake' or just the amp?
MattGold -

MY RESPONSE

In my case I got a replacement amplifier for the back (there are 2) by advertising (free) for one on this forum. However, in your case your problem is NOT the same as mine. Because all your speakers are non-functional, I would say that your head unit is bad (the centrally-mounted unit with all the controls on it mounted in the front panel of the car. You will likely be able get a replacement head unit on this forum, as above. There is a slight chance that the unit is OK and one of the plugs, (power or main output plug) has dropped out at the back of the unit, but this is unlikely, (do the display lights, {clock, radio channel, etc} on the unit light up? If so it's not the power plug). I would suggest the following diagnosis:
1) If the head unit is not "lit up," (NO), first check the radio fuse, (you can locate this from the various manuals in your car or available on this forum).
2) If that's not the problem, you have no choice but to pull the head unit out of the front panel. You cannot access the cables behind this unit without pulling the unit out of the car front panel. You need a special tool for this, (a few bucks at your local car parts store). Do not try to force the unit out without using the tool - otherwise you will break something. (You cannot access the cables behind the unit without first pulling the unit out of the panel completely). Check elsewhere on this forum for more instructions on removing the front panel of the head unit to access the slots on the head unit that the special tool goes into)
3) Gently pull and "wiggle" the head unit out. There are several cables connected to it at the back and they are stiff and take a while, (and patience), to straighten out and allow the back of the unit to become accessible.
4) If the answer to 1) was NO, you are lucky and the power cable has very likely unplugged at the back of the unit. Push it back on and try the system again before you put the head unit power cable back in.
5) If this is not the problem, unplug all the head unit cables. Note that there is not just 1, but 2 antenna cables to remove. These are not on the back of the head unit but are at the end of 2 short cables coming out of the back of the head unit. To get access to these plus you need to get your hand underneath the carpet and cover at the left -hand side of the passenger compartment. Then get a replacement head unit, as above, on this forum, (unless you want to have to sell your house to get a new head unit from a Mazda dealer!). NOTE: When buying the head unit make sure you ask for the one for the Touring RX7 3rd Gen. (I'm assuming that this is what you have because this is usually the model with the Bose tubes at the back, per my original post). The head unit for the "sport" model, {can't remember the official name,} is different and will not work on a car with the Bose tubes).
6) Install the new head unit in the reverse order of the above. You do not need the tool for replacement of the unit. Just push the unit back slowly and patiently, taking care not to snag any of the cables.
7) Yer done.

Good luck!

Dave

MattGold

iTrader: (108)

Dave I really appreciate you trying to help diagnose my issues. I probably should have given you a little more info.

- I originally had the (stock) touring head units (tape and CD). With these, I had the 'boooooong' sound from the tube and no other sound from any speakers while the radio was on.

- I replaced the original head unit with a Miata radio (wired correctly), but the sound/symptoms remained/were identical.

- The current head unit lights up and works properly - BUT when tuned to radio/CD the sound persists. Additionally, when the AMP output is not wired up, there is no problem - but there's also no sound. =)

I am now trying to figure out what *else* could be causing this. Like you mentioned, it seems like something more 'central' since ALL speakers are effected - rather then just one or two amps.

I think I will start with the BOSE Wave amps then work my way forward.

Any other ideas are welcomed and appreciated.

-M

davesan1

iTrader: (4)

Mattgold -

So from what you say, I believe that this problem has been there ever since you first got the car, (yes?). If this is so, I suspect at some time before then, somebody for some reason rewired the connections to the head unit. I say this because the symptoms you describe suggest that the connections to both the front (3) speakers and the back (2) amplifiers are not connected to the head unit at the correct terminals on the head unit, and are, in fact all open circuit. Then-

1) This would explain the total lack of sound from the front 3 speakers, (for these, if I remember correctly, the amplifiers are in the head unit and therefore no "amplifier-picked -up hum noise," {see later} would get into these 3 speakers so they would be totally silent, as you describe). You may be able to partially verify this, as follows: With the head unit switched off and the head unit volume control at its highest level, put your ear very close to one of the front speakers and then switch the head unit on. If there is ANY connection between the speaker and the head unit, normally you should hear a small click in the speaker. No click likely confirms no connection.

2) As for the 2 back speakers, they are driven by the 2 rear amplifiers, which in this scenario have open circuit inputs. This will cause the inputs to pick up and amplify a classic amplifier "hum" and broadcast it through the rear "tube" Bose speakers, again giving you the symptoms you describe. You can easily test this part of the scenario, because if my diagnosis is indeed the case, the hum from the back will not change volume as you adjust the head unit volume control, because there is no connection between the head unit and the amplifier/speaker combination at the back.

As for why this happened, I can only think that maybe the car at one time did not have the "tube" Bose rear sound system in it and the car wiring has always reflected this. After this, somebody tried to install the "tube" Bose system but didn’t change the car wiring. I do know that he main connector(s) on the non-rear- Bose-tube version of the head unit has (have) different pin connections to the one with the Bose-tube head unit, thus allowing for the possibility of the open circuit wiring I describe. (Note also that the rear speaker amplifiers are, I think, in the in the head unit for the non-Bose tube version and there are no separate rear speaker amps to generate the above discussed hum. Under this scenario, the sound system would have never have worked after the conversion, and there would have always been the symptoms that you describe after the conversion. Depending on the historic buying chain you may never know whether this is the case. Let me know any other info. you may have to help solve the puzzle, along with any results from the above suggested tests.
There is a link to the sound system circuit diagram somewhere on this forum. I’ve been looking for it, but I recently suffered a computer crash and, despite backup, it appears to have gone! I’ll try to find it and see if the things I am stating from memory are, in fact, correct. I also have some print-outs filed, which I will find, giving further confirming, or (otherwise!), info.

Dave

davesan1

iTrader: (4)

Mattgold -
OK, I found my circuit diagrams! Let’s start by calling the 2 versions of the car sound system Type 1, (no Bose acoustic wave speakers at the back, and type 2, (with acoustic wave, {i.e. the tube system}). Note that this is what they are called in the circuit diagrams.
My memory for couple of things was in error. What follows are the facts from the diagrams:
a) Type 1 drives all the speakers directly from the head unit. There are no external amplifiers.
b) Type 2 drives all speakers except the center speaker from external amplifiers which are in turn driven by the head unit.
c) (Clearly) the Type 1 head unit differs electronically from the from Type 2
d) Both type 1 and type 2 drive the center speaker from the head unit
e) Both Type 1 and Type 2 have 8 connectors on the back of the head unit, (excluding the 2 antenna connections).
f) Type 1 and type 2 head units each have a total of 8 connectors. For each of 7 of these connectors, those on type 1 HAVE IDENTICA L SIZE, SHAPE and AN IDENTICAL NUMBER OF PINS to their equivalent connector on type 2. The 8th connector on type 1, (which is for the rear sound), is PHYSICALLY different from type 2 and HAS ONLY 2 PINS WHILE 2 TYPE 2 HAS 6 PINS.
f) Electronically the signals on each of the 7 type 2 connector pins above are identical to some of the type 1 equivalent connector pins but there are also additional signals on some of the Type 2 pins which are pins that just spare and unused on the type I equivalent connector. For the 8th connector the type 1 just has 2 pins for the single rear speaker while the type 2 connector has 2 pairs of pins for sound for each of the two speakers plus 2 pins for the 12 volt power to the rear amplifier, a total of 6 pins.
So here’s the new scenario. Assume for the moment that you still have the type 1 head unit but that all the rest of the system is type 2. 7 of the 8 connectors would physically plug in directly to the existing wiring, just as if it was a type 2 unit. My guess is that the 8th connector would also physically plug in because I would be willing to bet that there is a 6 to 2 pin converter behind the unit to allow Mazda to use the same 6 wire cable for this connector on all models by just discarding the 4 unused pins for type 1 versions. So, from the head unit’s PHYSICAL connection viewpoint everything would look OK with a type1 unit plugged in instead of the required type 2 head unit
However, in this scenario, (which I think is the likely cause), because of the missing additional type 2 connector signals that are needed by your otherwise complete type 2 system, you would see some problems, as follows:
Side speakers: Because your type 1 head unit does not supply +12volts to the “spare” pins on the 7 connectors discussed in f) above, (as opposed to the correct type 2 head unit, which does supply the +12 volts), the external side speaker amplifiers would not work. You would receive no sound from their speakers.
Front speaker: This should still work, because the amplifier is inside both the type 1 and type 2 head units. First try turning the volume up higher and see if you can hear anything at all, even just a scratching noise, coming from it. Try tapping the panel above the speaker and see if you can get a crackle from it. If there is still nothing, be aware that it is not at all unusual for this speaker to break as a result of vibration, (mine did, but I was able to fix it, more on this later when you get the rest of it going).

Back speakers: These are clearly receiving power somehow. My guess is that somebody did some wiring changes behind the radio to add a +12v and Ground input to the 6 pin connector discussed in f) above. This would also need an adaptor for the amplifier for the back speakers, (in the driver’s side of the trunk, more later). This is easy to get mixed up. I suspect that it is only passing through the +12v & ground signals and not the proper speaker signals from the head unit. This would provide the loud hum
So, I believe that your problem could be that nobody changed out the head unit. When you changed the manufacturer, it was probably for a unit that had the same basic system design as the then existing Type 1 head unit and thus showed the same problems.
Try pulling out the head unit and having a look behind it. You can tell by the connectors at the back whether it is type 1 or type 2.
Let me know and we’ll go from there, if you’re not fed up with the whole procedure by then.
Dave

MattGold

iTrader: (108)

That was a lot of reading... but thank you.

Here's what I know:

- There is no doubt that this is a Touring Model and has been a BOSE system from the start.
- The original head unit was removed and replaced with another working head unit.
- The replacement head unit was a Mists BOSE CD player, so all connections were correct (Type 2)
- The new head unit is wired correctly and the had unit functions correctly.


I have since removed the BOSE snake but still no sound from any of the other speakers. I will try to diagnose using your methods to see if I can hear the power 'click'.

It is also interesting that I get no Center speaker noise if the head unit is powering it.

I will continue to diagnose and keep you posted. Might send Wave Amp out for a rebuild as a shot in the dark.

-M

MattGold

iTrader: (108)

Quick, good news update.

After I pulled the Wave today I went back to finish up some other projects. In addition to the speakers having issues, the antenna wasn't working. I went in and disconnected the power so I didn't have to listen to the whirring, and unplugged / started to reroute the actual connection so I can switch to a rear glass mounted antenna.


Annnnyhow, I tried to turn the speakers all the way up and listen for the 'clicks' - but nada.

Then I thought about what you said regarding the center speaker - so I smacked the dash a few times...all of the sudden - BINGO - sound! Not from the center channel, but from the passenger speaker.

Long story short... I think the Wave Amp is toast. I will either have it rebuilt or buy a new/used wave. I also think the drivers side amp is done. I will do the same for that. As for the center channel, jury's out on that as I may end up going with a tripoint pod and replacing it.

Thanks for the help - and here's to not being above slapping my car around once in a while!

nelson93rx7

I have a 1993 mazda rx7 only 33,000 miles I want to keep it stock: I am having a problem with one of the rear amps in the snake. does someone have one?? also could use the stock cd player head unit.

theorie

iTrader: (31)

I spent a lot of time trying to fix the Bose "subwoofer" so I could keep the system, but eventually gave up.

I tried swapping the sub with an aftermarket one, and then using an external amplifier, but no matter what I just couldn't get it to sound the same. Still sounded alright, but definitely not the same...

Now I only have door speakers but I don't listen to radio much anyway. haha

Some photos from when I was messing around with it:



Installed different 6.5" speakers...

shmacklepap

iTrader: (15)

Theorie, how did it end up sounding with the aftermarket speakers installed? I had no idea the factory subwoofer setup were mounted towards each other like that...strange

Narfle

iTrader: (16)

He never got it to sound nice. Removing/replacing the bose system is really the best option.

pito13b

iTrader: (3)

Agree 100% I have a cheap setup in the car now with the door speakers and a bazooka in the back and it sounds so much better.

Fortune_Seven

iTrader: (24)

Yanked all my Bose as well and went with component speakers in the front and rear. Sounds good and doesn't take up any extra space.