I got mine replaced today too. It took about 1.25 hrs. Not bad considering they had to rip apart the interior of the trunk to replace the amp. The self volume adjustment is fixed SOMEWHAT. It still adjusts by itself slightly... but barely noticeable. After the new amp is in, I think the base doesn't thump as much as before. Hmmm... I'm not quite sure if this was "the fix" for the problem. It feels to me that they just tuned down the amp power so the self volume adjustment is not that noticeable. Any thoughts on this??

 

yeah i hope that nissans "fix" doesnt just detune our 240watt system to a 140 watt system.

 

I think the fix is fine. I have yet to notice a volume change and I can now listen to the radio, which used to sound so crappy that I couldn't stand listening to it. This is the way it should have always been. I have not tried opening the window (there is snow on the ground) to see if the volume compensation thing works. I am fine with it not existing as the car is very quite inside, sounds like something designed for the convertible.

 

Ya know I just gotta add my 3.8 cents... I am dissapointed that you cannot turn off the drunken Audio Pilot. Even my Piece of Sheeot MINI Cooper has 4 levels of sensitivity and an off setting.

I sure hope mine gives me no problems when it comes in.

GL to All-- As I recall the Bose in my '92 started crapping out with the right rear followed quickly buy all locations. A new head unit, amp and custom Fiberglass enclosers fixed that problem.

It was a shocking day when I danced upon my smashed bose head unit only to find a clarion sticker on the bottom. :-(

YIKES! or Jinkies or whatever...

 

I am RETURNING the Bose system!!!!!
I had it with this sound system on my touring. This was a big blunder for the Z...............I am demanding the Dealer return this system to Bose and refund my money. I will not take "no" for an answer. If they will not do this..I will uninstall the system and return it to Bose myself. Does anyone else feel this way?
Is there some way all dissatisfied Bose Z owners can do this together?

To Nissan:
To rebate or not to rebate, that is the question!

Thanx,
Grogs

 

I do agree that the fix is a world of difference from the original pre-replacement amp sound... but if you put this into perspective of the components in this car with a 10 inch subwoofer... there sound is completely flat! It seems they have setup the processor of the amp to de-tune or make the Bass flat no matter the head unit setting. When the original amp was in this car, you could hear the potential of the system, especially with a CD. Now, you have to crank it to about 25 to get any bass response.

I'm not expecting this to sound like a $1000 aftermarket system, but this is inexcusable!

Almost any stereo in any other car will sound as good if not better than this and we paid for a "Premium" sound system. Have you read the Marketing in the brochure that came with the Lust, Then Love package? It's a joke!

I called Nissan North America and described the flat sound and that the autovolume adjustment still does not work correctly. When you slow the car down.. a few seconds later .. the volume actually goes up!.. not down like it should.

I don't expect this system to be boomy and real bassy (if that's a word), but it doesn't even realistically reflect the actual recording.

Please!!! Even though this seems much better than the original.. put the performance of the sound system after the amp replacement into perspective with how much we paid for this and how much we should expect!

Numbers speak volumes and my single complaint won't get anywhere. If we want justice, we all have to voice our opinions to 1-800-NISSAN1.

Thanks for your time!

 

I agree with alot of what has been said about the stereo being a big dissapointment. Even after the amp replacement the bass is now gone and the subwoofer basically does nothing now.

This weekend I am going to disable the audio pilot microphone and see if this helps. If anyone else wants to give it a shot here is the short description from the service manual on the audio pilot function and how to remove it.

 

From Service Manual

 

From Service Manual

 

Nope, the probelm is in the amp located in the rear of the vehicle that controls the Audio Pilot which is connected to the mic that "listens" for cabin noise and raises/lowers the volume.

 

Let us know if that's a solution to the problem (disconnecting the mic). It's not that big of a deal for me to reach over a (manually) turn the volume up or down. I'd much rather do that than continue dealing with Nissan over this problem.

 

The mic is the source. It tells the Audiopilot how to modulate the amp. Remove the mic, remove the source of the problem and no more volume fluctuations. I'm very interested to see if this works.

For more info. on the Audiopilot and the bose system in general (complaint related), please see: https://my350z.com/forum/showthread....threadid=13004

 

Have you tried removing the mic and that's why you say it won't work?

I am thinking also that Bose my just be changing a resistor or something stupidly simply inside the amp to reduce the audio pilot effects. I wonder if there could be a simply pot resistor or something stupidly easy like that we can adjust?

I don't think this will ever get resolved to the point where people are happy and so it will fall on each owner to fix it themselves or replace the system.

 

No experience here just information about the amp. and dealing with my dealer.

I had mine replaced this week and have lost all bass response now. I'm very interested in hearing if removing the mic works.

 

I will be taking out the mic this saturday and see what happens. I will update this thread with the results.

If you want me to email you an update directly please send me your email address to reply to at
jelledge@earthlink.net

As soon as I try it I will send out the update.

Regards,
Jason

 

Please let me know what your findings are with removing the mic.

If that doesn't work and Nissan doesn't do anything else.. I'm going to start looking at bypassing the gain control on the amp/brains in the rear. I don't know if you've checked this or not, but the subwoofer has it's own amp next to it in the enclosure. It probably receives the gain adjustment from the amp/brains in the back. The amp in the back directly receives the bass gains -5/+5 from the head unit.

 

I am an engineer with significant audio hardware design experience. I would caution anyone in simply disconnecting the microphone and leaving that input entirely unterminated. Leaving it open may work OK but could cause widely varying performance, (at different times, unexpectedly). Information in the service manual suggests that it is a "condenser", (capacitor), mic.

Try this instead:

Obtain a 100 microfarad tantalum capacitor, (~15 volts min.), a 1K, (1x10e3), ohm and a 1 Meg, (1x10e6), ohm film resistor, (.25 watt min.). Radio Shack, etc.

Solder one end of the 1K resistor to the positive terminal, (wire), of the capacitor.

Solder the 1 Meg ohm resistor from the capacitor negative terminal to the open end of the 1 K ohm resister.

Unplug the microphone connector at the microphone.

Connect the wire from the negative capacitor terminal to microphone connector pin 2, (Blue/Green wire), and the junction of the 1 Meg ohm and 1K ohm resistors to microphone wire connector pin 1, (Blue/Yellow wire). Be sure that no bare wires touch anything, (electrical tape, whatever).

Doing the above will preserve the DC voltage, (mic. bias), and short the AC, (sound), components to the microphone input. This should make the amp "think" that no sounds at all are present, and hence it won't have to do anything to change audio levels, etc.

I haven't had time to try this approach on my car yet. So far I have put electrical tape over the mic. holes and this has helped somewhat but low frequency vibrational components still have an effect. Regardless of how well this does or does not work, it is better to do this that either shorting together or opening the microphone input to the amp. Shorting the input could cause damage to the amp module. Explicit technical details of the audio hardware would provide better information that could yield a better solution. Based on a number of posts I've read, I'm definitely NOT going have the Bose amp replaced per the Nissan TSB. This TSB does not appear to be a definitive proper fix for the problem. The proper fix would find all those who used it in complete agreement as to the performance result.

Good luck!

 

Yeah I figured you could not just leave the wires unplugged or short them together. Thank you for the advice I will give it a try as you suggested and let everyone know what happens.

 

Ok boys and girls, I did a little Friday afternoon experiment with the microphone.

First I just disconnected it, as ZNETUSER predicted the sound was all over the place. The unit just did not seem to know what to do so it tried to do everything, bass and treble floated all over the place.

Next I built the circuit suggested by ZNETUSER although I did not build it exactly. The only tantalum caps The Shack had were 1 or 10 microfarad, I went with the 10 since that was closer to what was listed. With the mic disconnected and the circuit in its place the radio sound still did not seem to know what to do, the bass would change from one note to the next. One second it would be ok the next the sub was trying to jump out of its mounting. The cd player sounded fantastic for the first couple of minutes, at bass 0 it sounded good, at bass +2 there was a definite kick in the back with each deep bass note. After the first couple of minutes the bass started to self adjust at random again, not as bad as the radio but definitely not good. If I turned the car off and back on it would be good for a couple of minutes and then start drifting again. During the couple of minutes that it sounded good I tried playing with the adjustments and noticed that if the Fader or Balance controls were set any further than +/- 2 then the sub would almost completely shutdown but as long as it was in the +/- 2 range there was more than adequate good bass.

ZNETUSER, would the 100 microfarad improve upon this or was the 10 close enough for testing purposes? I could track down the right cap on Monday at a better electronics supplier.

My replacement amp is on order from the dealer but I am leery of what others have experienced with the swap out.

 

Re.: Microphone Experiment

tbob and others,

Sorry it didn't work better. (In the case of tbob's work on this it's discouraging that it was not stable with the parts connected). It should have a better chance of being successful when using a larger capacitor value. Although unwieldy to work with, 10 of the 10 microfarads in parallel would yield the 100 microfarads. (Connect all positive leads together and all negative leads together). I really wish that I could guarantee a good result but what's inside the Bose, as mic. input circuitry, unfortunately isn't available. I apologize ahead of time if I cause anyone to spin their wheels on this. What's inside the Bose amp could be as exotic as DSPs doing signal processing down to poorly designed analog circuitry. Clearly they didn't get it right! Normally I would have tried this out before mentioning it, but it's cold here in S. Jersey now and to really have enough space I need to work in the driveway to have the doors wide open on the car and work comfortably and it requires the available time. Below is part of a PM to another member where I outline what the fix should do. Again I apologize if I cause anyone unproductive inconvenience on this.

*********************

Unfortunately we don't know any tech details about the circuitry. Hence we must infer what's, (could be), there from the available info in the Service Manual. The Service Man. indicates a minus, (pin 2), to plus, (pin 1), of 6 VDC at the mic. I assume this to be a DC bias voltage for a condenser mic. element.

So called "condenser" microphones are really capacitors. They require a DC bias voltage across them to work. The capacitance changes as a function of the capacitor changing value based on the audio pickup. The changing capacitance causes the current to fluctuate at the audio rate and appears as a voltage change as the resulting current changes are dropped across the input resistance/impedance of the mic. input circuitry. Voltage amplifiers then amplify the small audio signal to useful levels.

The component values that I picked are not calculated values but are ball park guesses. Calculating the best values is not possible without knowing what's inside the Bose amp, (circuitry), and what the mic. really is.

The 1 Meg. resistor just provides some DC termination, (less than infinity), at the mic. input. I would expect that 1 Meg. is a much lower DC termination than the capacitor element itself though. So the DC component of the mic. input termination is 1 Meg.

The 1 K resistor and the 100 microfarad capacitor, (in series), at audio frequencies make the AC termination near 1 K ohm. Film resistors are generally low noise as compared to, for example, a carbon resistor. Hence the use of film resistors.

So the 2 resistors and the capacitor attempt to look like a signal of zero to the mic. input - no audio, completely quiet.