insaneamine

iTrader: (1)

Well, actually, $0.99 because the resistors come in packs of five.

I stole this information off of another forum. I have added to it through my own experience. It worked for me!

This modification negates the auto adjusting effects and the “boominess” of the system.

IT WILL PROBABLY VOID YOUR WARRENTY TOWARDS ANY STEREO RELATED CLAIMS!

Required: ¼ watt, 1k-ohm resistor. Radio Shack part #271-1321.
Phillips screwdriver.
Heat shrink tube or electrical tape.
½ Hour.

1. Remove the lower kick plate under the steering column. There are three screws; one to the far left under the side kick plate, one just under the steering column towards the left, and one far right against the center console. The top snaps in.

insaneamine

iTrader: (1)

2. Remove the steering column under housing. There are four screws; one is under the column adjustment lever. Pull the steering column under housing down, it is snapped in also.

insaneamine

iTrader: (1)

3. The microphone is attached to the inside of the under housing. Unscrew the microphone and unclip from connector. Save for later, if you decide to replace it.

insaneamine

iTrader: (1)

4. Cut off about half of the resistors “legs.” Bend directly at resistor body. Plug the resistor into the microphone connector. The resistor needs to go into the smaller holes of the plug. Finish off with some heat shrink tube or electrical tape.

insaneamine

iTrader: (1)

5. Test it out.
6. Replace steering column under housing and then the lower kick plate.
7. Enjoy.

slaponte

iTrader: (2)

LOL! You make me smile...

Of all the crazy Hungarians I know, and most of them are, you are the tops.

Great post! Thanks for the info. Now I have a little project for this weekend...

slaponte

iTrader: (2)

If it is that simple, don't you think a small switch could be wired in line to turn it on and off??

Add on to your kit business...

abz123

Is this for real?

If this works, this has to ranks up there with using a magic marker to decrypt CDs.

insaneamine

iTrader: (1)

I installed the resistor and drove around a bit. I played both CDs and the radio. The volume did not auto adjust and the bass and treble levels remained where I set them.

I suspect the microphone and the circuitry was acting as a variable resistor. The inherent resistance to the mic is 8k ohm.

I read another post here, where the author tried resistors ranging from 3k to 10k without luck. Maybe he didn’t go low enough.

This mod is fairly simple and unobtrusive. Try it. Post your comments if you disagree.

Here is a picture of the underside of the beast.

aelius

Rather than disconnect the microphone, itself, would it not be easier simply to cover the microphone grill with a bit of black electrical tape?

syf0n

Holy *****!

insaneamine

iTrader: (1)

The original post can be seen at www.club350.com by danstam in the Mobile Electronics section.

abz123

For the electrically challenged, what is this actually doing?

KJ-350

Pretty funny b/c I had to do the same exact thing in my GTi when I installed my Sparcos to keep the sensors and ECU from reading an empty or faulty airbag harness and throwing a CEL (but it was a 4.7 1/2 watt)

Basically it is keeping the feedback level constantly at one / the same point! The system is getting volume reading as if the mic were still in place b/c the resistance is still there! But since the resistor is in Vs the actual mic its not going to have different levels to send back for an increase or decrease the levels for the autopilot!! It will keep the loop constantly at one level regardless of your actual speed or amount of noise in the car! Where as disconnecting the mic altogether would just break the loop of sending and receiving! I don't know what exactly it would b/c I didn't remove my all together but I would assume it would give some type of error, CEL, or may cause the stereo to sound even worse.

I'm definitely going to try this one since it worked for me before! Funny how sometimes the biggest issues / problems end up having the smallest fixes that are right there in front of you!!! Thanks for the post, I 150% agree that this should get a note up top!!!!

insaneamine

iTrader: (1)

On my ride in to work this morning I put in one of the most dynamic new CDs that I have. The Foo Fighter’s latest, One By One. This CD R-O-C-K-S!

Anyway, I set all the levels to Zero. I playes at low and high volumes. The sound seems fine.

Don’t get me wrong – this is no a “cure all.” The Bose System is still very bottom heavy. But at least it doesn’t over compensate itself.

Again, if you don’t like the results, replace the mic and you are back to the original. Please post your feedback.

onecoolee

Being a EE...I am surprised that this works. Here is the reason why...

Typically Condenser type microphones, consist of a transistor, and capacitor. Together these provide a sensitivity to whatever is being picked up by the mic input. Essentially, the microphone is excited, or driven with a voltage, and the driving circuit waits for feedback or changing voltage levels from the feedback loop. I assume that since the Audio Pilot technology adjusts the sound levels for certain frequency ranges, that there is some built in circuitry to detect levels at certain frequency bands. These levels are what the factory Bose amp is look for to determine whether it should boost levels in certain ranges or not.

Here is the problem. This microphone has an impedance associated with it, therefore, a voltage drop occurs across it when it turns on, essentially when the audio pilot is activated. It is on whenever the stereo is on, so it always loads down the input/output of the amp. There is no way to substitute a simple passive component (a resistor) for an active circuit (FETs, transistors, and capacitors). This uncommon or improper loading of the audio pilot cuircuitry in the amp, I would think, would send the audio pilot mic feedback, out of range and give you inconsistent results. You cannot disconnect the mic, as several have already tried, the result is 10X worse, and obviously, the amp has to be loaded down. The bottom line is that there's no way to properly simulate normal loading conditions (uncompensated frequency levels for audio pilot in a normal state), by simply replacing the microphone with a 1kohm resisitor. Disconnecting the mic would be similar to switching it on and off, so a switch is not the solution either.

But hey...if it works, and more than 1 person have the same results...great. Maybe there is something more fundamental going on with the audio pilot feedback circuit than what I expect, and if thats true, this fix could possibly work. But, if you look at the electrical characteristics of the mic circuit and system, it just doesn't look like a simple fix like this would work. I am no PhD, and I have been wrong more than once, and I have seen some strange things in my life, so I would suggest a few others try this and prove it works, before we rely on what makes sense.

By the way, I still feel that the best fix for the Bose is a total gut-out. The system has horrible dyanmic range, low s/n ratio, and poor frequency response. I removed the head unit, replaced the speakers with some nice JL Audio seperates, installed 2 quality amps, and am currently working on a custom fiberglass 10" sub enclosure for the left rear portion of the hatch. My sub-less system sounds better than the factory system, and has more bass. You can see a comprehensive component list below...

Please keep this thread going, as I am curious top see what others find as a result. The best test for htis fix is to use the radio, and not a cd, as mine seemed alot more sensitive to radio and often overboosted the bass using the radio. Obviously, it doesn't do that anymore with the new head unit, and after the system was replaced, I am even happier with my Z...

insaneamine

iTrader: (1)

Thanks for your post onecoolee!

Here is from the Service Manual:

AudioPilot™ system

Audio Pilot™ is the sound improving system that picks up any noises or the sound of music coming into the vehicle by a microphone under the steering, and

that the BOSE speaker amp. revises the frequency feature of music at real time in response to the frequency feature of the noise while driving and listening

to music.

- If low frequency area noise from vehicle is loud, it adjusts low frequency element of music to be bigger than vehicle noise.

- If high frequency area noise from vehicle is loud, it adjusts high frequency element of music to be bigger than vehicle noise.

- If vehicle noise is smaller than the setting volume, correction is not performed. This eliminates vehicle noise when listening to music.

Vlad

Holy $h1t!

I always wondered if we can just get rid of mike...
I'm going to do it tonight first thing after work.

I'm going to enjoy mutilating Blose.... I'm goint to do it slow, very slow. And then I'll throw mike to my ferrets ( ) to play with/sharpen their teeths... O, it's going to be a pleasant evening.

Hope it'll work for me until I'll get money for final fix which is to replace pure thing with some descent audio.

abz123

Have you had the TSB fix too insaneamine?

Anyone who tries the mic fix please post results here...positive or negative.

This might be on the Sunday afternoon 'to do list'.

onecoolee

Please post your findings...all here with the Bose system will benefit. I still have some doubts about this simple fix, but the only way to make sure it works or doesn't work is for a few people to try it out with good results...for me, I could care less about the fix, with a new head unit, and no more signs of anything manufactured by Clarion/Bose, but alot of others could benefit from any of these findings...

By the way, the only way to really know if its working is to use the original amp, manufactured before the TSB came out, since the problems seemed to go away after the new amp covered by this tsb came out. Anyone who has a Z with audio equipment manufactured before Oct. 1 by Bose/Clarion, please post any findings...