# Serious issues with my JBL MS-8, could use some help



## blackreplica (Mar 14, 2005)

Guys (particularly Andy), i could use your help

I have just finished my installation of the MS-8 into my Lexus IS250 (the same car model featured in the MS-8 video i saw on facebook that someone posted in the MS-8 thread). 

I am running a 3 way front setup with center and sub. Speakers are the Alpine SPX-177r tweeter, Fostex FR-88 mids, and Seas W16NX midbasses. Stock sub. Amplifiers are the Alpine MRV-F407 and MRV-F409. Stock headunit from the Mark Levinson Lexus sound system

Input signals are tapped from the Mark Levinson Amp to the MS-8

I took extra care to read every post in the MS-8 thread and did everything i could to minimise the chances of problems occurring. All gains are set at 2V. Subwoofer input to channel 8. All levels are roughly matched (tested with an SPL meter during the input setup). Input setup gave me a signal OK, level OK, balance OK at about 40 out of a possible 60 on the HU volume control. Calibration was carried out at varying levels, never too loud (i used -20 on the MS-8 most of the time as when the calibration was carried out, levels approximated normal conversation levels as per the manual). The microphone was disconnected after calibration etc etc. I'm not sure what else i could have missed out. 

Here is the problem in a nutshell: Regardless how i many different ways i run calibration, the result is always the same. I have this awful sound being generated when playing any kind of music. It sound exactly like mic feedback, an irregular, frequent 'woooo wooooo' sound that keeps playing over my music, it ruins everything and gets worse when i turn the volume up, but is always present. The same sound gets generated when i plug and unplug the mic into the MS-8 when it is switched on (even if the head unit is switched off). It gets 100 times worse when using my iphone connected to the aux in input on the mark levinson head unit. Music becomes unlistenable. When i play IASCA test tracks like polarity, phase, left-right channel etc from my iphone, the sound is pretty much rubbish, the sound drifts left, drifts right, gets louder, gets softer, goes in and out of phase, cuts in and out...its like the MS-8 has no idea what to do with the signals, going nuts

When i play CDs from the head unit, its a little better but still there and present on every track. When i drove the car around, i found the the right and left channel occasionally cutting in and out, music would go soft, get louder again. It would happen nonstop without touching the volume knob and the amps were functioning normally

Seriously i got so frustrated it took great effort of will to keep myself from ripping out the ms-8 and throwing it out the window. I must have run calibration like 20 times, trying everything i could. Nothing is working. That feedback sound never goes away, no matter what i do.I'm probably one of the first people to use this unit where i live so its up to me to find a solution Someone help me!

Also as an aside, i am far from happy with the autotune result. I am not very impressed with it at all. First of all, the levels are way off. When the calibration tones are being played, it sounds very balanced, but once tuned, there is absolutely no midbass, and the mids are far too high in level. Its sounds absolutely clock-radioish, not hi-fi in the least. Center image (even with center channel) is offset to the left. And there is almost no stage information between the center channel and right speaker (For information's sake, i drive a right hand drive car). Everything sounds compressed to the left side. EQ boost and cut on the MS-8 sounds unresponsive to anything but very large changes.

I'll answer any question i can about how i set it up. I just want to solve this problem and get on with it. The way it is now, the system is completely unusable. Its the worst result i ever got with any piece of hardware in the 10 years i've been in car audio. Seriously, has anyone ever come across all that massive feedback when they used the MS-8? I'm tempted to say its defective but who knows? I might be doing something wrong here and i'm hoping there is this small magic thing i'm missing which will make my problems all go away. I'm very disheartened at the moment as i'm sure you can tell.


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## AAAAAAA (Oct 5, 2007)

Have you tried listening in your car without the iphone in your car? No cell phone at all?


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## blackreplica (Mar 14, 2005)

Probably not...will give that a shot right now....also am gonna try to see if shifting my head during the autotune will solve my imaging bias issues, as per the tips and tricks thread. But i still have no idea what to do about all that massive feedback


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## blackreplica (Mar 14, 2005)

Ok ran another input setup/calibration. Engine off this time, phone left outside the car. Unplugged the mic with MS-8 off so i wouldnt get that super annoying feedback as i pulled it out of the jack

No joy. Still feedbacks like a *****. Most pronounced when the vocals on my music kicks in. Also feedbacks with the basslines, and just about everything really. I even get a short feedback pulse when i switch tracks. Its an incessant warbling kind of feedback sound that is really starting to fray my nerves

When i turned the volume up, the music and feedback gets louder, and i notice the left and right channels slightly cutting in and out. Based on memory, the cutting in and out and phase shifts and balance issues seemed worse when i was listening to it while driving home just now

Still absolutely no midbass output. And shifting the head does indeed help move the center image. Moved my head to the left during calibration, and now the center is offset to the right instead of the left. Will have to mess with my head position a little more once i've sorted out the feedback problem, which is the main issue really Its still driving me nuts and i cant think of what else to do


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## 14642 (May 19, 2008)

Run acoustic calibration with MS-8's volume at -40. I'm looking up a wiring diagram for the car now.


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## 14642 (May 19, 2008)

OH. I'll be in Singapore on July 28th. I feel certain we'll get your issue solved before then, but if you have a few minutes on that day, I'd like to meet you and hear your car. Will you be available?


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## blackreplica (Mar 14, 2005)

last few observations, i've given up for the day

Feedback does not change in level whether mic is plugged in or not

Feedback stays no matter how i configure my gains and no matter how many times i run calibration. 

The feedback gets worse the higher the volume. Problem is, the MS-8 configures its outputs to give almost nothing until very high volumes on the headunit, which makes the problem worse. Input setup is run at vol 40 (of 60), and if i listen to music anywhere approaching that volume, like 32-35 (which is only about 90-92db), i hear more feedback than actual music. Even at whisper quiet listening levels, there is still feedback, albeit less of it. 

As the volumes get higher, i also hear the channels cutting in and out, balance and phase wandering etc even more.

Is anything other than a faulty unit possible here?


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> Run acoustic calibration with MS-8's volume at -40. I'm looking up a wiring diagram for the car now.


Andy, its good to see you in this thread

I dont think that the tones will even be audible at -40, but i'll go try that now.

yes i am in town on the 28th. This is quite fortunate as i am out of town often (i am a pilot). I would love to meet you when you are in town. But if there is something you can do to help with my problem before then, more's the better!

Give me about 20 mins to run the cal at -40 and i'll get back to you


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## 14642 (May 19, 2008)

I feel pretty sure that there are a couple of issues here. One may be that the sweeps are too loud during calibration. The other is most likely the factory active noise cancellation, which has no idea what to do when an additional EQ is placed in the system. The diagram below is for a 2009 IS250, but a left hand drive version. Look for the connector labeled JR1 (I'll bet it's on the other side in your car). If your car isn't 2009, and you don't find this connector, please let me know the year of your car and I'll go do some more research.


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## AdamS (Dec 22, 2009)

OK, let's split your problem into 2 (UnEQ vs Acoustic EQ).

To determine if UnEQ/head unit is your issue, please do the following...

Connect your Iphone directly to MS-8's AUX in, not the Levison/IS250 Aux in.
Switch the MS-8 input to to Aux.
Play your music.
If not enough gain from your Iphone, increase the Aux level in the System Levels menu.

Post your result.


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## blackreplica (Mar 14, 2005)

Ok guys, thanks for the help so far. Calibration run at -40. No change, still feedbacking

Andy, you're spot on, my lexus is indeed the 2009 year model (the one with the indicator lights on the side mirrors, the facelifted version). That wiring diagram should apply to my car

My MS-8 is installed in such a way that i do not have direct access to the AUX input. but i am revisiting my installer tomorrow so i'll get him to open her up for me and i'll give your suggestion a shot too, AdamS


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> I feel pretty sure that there are a couple of issues here. One may be that the sweeps are too loud during calibration. The other is most likely the factory active noise cancellation, which has no idea what to do when an additional EQ is placed in the system. The diagram below is for a 2009 IS250, but a left hand drive version. Look for the connector labeled JR1 (I'll bet it's on the other side in your car). If your car isn't 2009, and you don't find this connector, please let me know the year of your car and I'll go do some more research.


Crap...those pillars where the JR1 connector is located is right where i decided to mount my midrange and tweeter on fibreglassed pods. 

I did spend a few days driving around without my pillars (while they were getting trimmed out) and noticed that connector thing on the left side. There wasnt a similar connector on the right. I thought it might have been a wire harness for my sunroof or something)

When i visit my installer tomorrow i suppose i could get access to it...but what should i do? Disconnect the entire harness?


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## blackreplica (Mar 14, 2005)

Oh dear its already 1am where i am and i gotta get to bed. Will check up this thread once i wake up later today before i head back to my installer. in the meantime, if there are any suggestions as to what to do in addition to what has been advised already, post it here and i'll give it a shot. hell, i'll give anything a shot. 

Andy, if you have any idea what i should do to the JR1 connector, let me know with the specifics and i'll get my installer to do it. Just post here and i'll get it done later today


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## blackreplica (Mar 14, 2005)

Andy and AdamS (and anyone else reading this)

Major breakthrough: I couldnt let this issue go so i went down again to try AdamS' suggestion of using the AUX input of the MS-8 instead. It took a lot of work (and a little pain) to stick my hand into the crevice where the MS-8 was mounted and plug the RCAs in, but it was worth it

My jaw nearly dropped to the floor when i played the first song using the AUX. All the problems went away! Not a single hint of feedback, not a single distorted note or channel cutting in and out, regardless of volume. Even better, the sound was fantastic! I couldnt believe how much my Levinson HU (or amp) was crapping the outputs. It was unbelievable, now i understand why so many are raving about the result of the processor and why my result was so different. The midrange is still a little high in level for my tastes but the midbass is back, and i am sure i could easily fix it with a bit of gain tweaking. The staging and imaging was magnificent.

The only small oddity i found was this: playing the IASCA "my voice is in phase, my voice is out of phase" track, i noticed that when the out of phase portion played, the sound almost completely dropped out, it was as if any out of phase signal was being deleted by the MS-8. Probably something to do with the fact that i am running Logic 7 with a center but no sides/rears ( i think i recall Andy saying something about out of phase info being steered to the rear in logic 7). but just to be safe i thought i'd mention it. Everything else, particularly proper musical tracks were fine

I guess this completely eliminates the MS-8 and everything downstream of being the cause of this mess. Run off the head unit, things are still crap. I just cant believe how much the Levinson system is messing with the signal....not just with the noise, feedback, and distortion, but how it was completely ruining the autotune result of the MS-8 as well!

Do you guys have any idea how i can get the factory head unit and amp to give me a clean signal? I'll try anything to get it working as well using my factory system as it does with my iphone on the MS-8 AUX in!


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## AdamS (Dec 22, 2009)

So now we know it's either the head unit, signal summing (UnEQ), or some odd combination of the two...

1. make sure ASL (levelizer) is disabled (I have it on stock IS250, I'm not sure what you have). You can add it back in when setup is working.
2. if a loudness curve is available via button push, make sure it is disabled. you can also add this back in later.
3. look into any noise cancelling microphones feeding back into MS-8. Andy can help you with this. You may need to cut these lines.
4. Tell me which inputs from Levinson (front low, front mid, front high, etc) are connected to the MS-8 and which channels are they connected to?
And are they high level or low level?
5. What Lexus head unit volume range do you get OK, OK, OK during input setup? Which did you run Input setup with?


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## AdamS (Dec 22, 2009)

blackreplica said:


> The only small oddity i found was this: playing the IASCA "my voice is in phase, my voice is out of phase" track, i noticed that when the out of phase portion played, the sound almost completely dropped out, it was as if any out of phase signal was being deleted by the MS-8. Probably something to do with the fact that i am running Logic 7 with a center but no sides/rears ( i think i recall Andy saying something about out of phase info being steered to the rear in logic 7). but just to be safe i thought i'd mention it. Everything else, particularly proper musical tracks were fine


And yes, out of phase stuff goes to the sides/rears, so you'll lose it. There wasn't an easy way to add that back into the fronts for our supported configurations.


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## blackreplica (Mar 14, 2005)

AdamS said:


> So now we know it's either the head unit, signal summing (UnEQ), or some odd combination of the two...
> 
> 1. make sure ASL (levelizer) is disabled (I have it on stock IS250, I'm not sure what you have). You can add it back in when setup is working.
> 2. if a loudness curve is available via button push, make sure it is disabled. you can also add this back in later.
> ...


AdamS,

1. ASL was disabled prior to the installation and remained that way throughout. I have all settings (Balance, Bass, Mid, Treble, Surround) at zero. The only nonzero setting i have is Fader at full forward, as my rears are still connected to the amp but, obviously, i dont want to hear them working once the MS-8 was installed

2. Dont think i have a loudness function on the Levinson head unit

3. I'm racking my brain to think if i ever saw any microphones in the car but i cant think of any. I dont ever recall seeing one. Hopefully Andy can help me with this

4. OK as far as i know: I instructed my installer to only use all the front speaker outputs + sub from the factory amp to be connected to the MS-8. Channel 1 + 2 of the MS-8 is getting the signal from the Front channel mid/high of the Levinson amp (the levinson splits this output via passive crossover for the tweeter/mid combo, according to my installer). Channel 3 + 4 gets the signal from the Levinson Front channel midbass (which is dedicated). The remaining signal is tapped from the subwoofer output of the levinson amp which is wired to channel 8 of the MS-8. All are high level inputs tapped from the speaker outputs of the levinson amp.

Also something i thought i'd mention: as part of the troubleshooting process, after input setup + calibration, my installer was constantly swapping input signal polarity as i played music to see if something out of phase on the input signal could be causing the problem. I remember that as he switched them, the sound produced was changing dramatically. Sometimes the mids would sound wierd, other times the midbass came back but the treble disappeared, funny stuff like that. after messing with it nonstop, i gave up and told him to wire it back the way it was done originally. My question here, does the polarity of the input signal matter or does the MS-8 correct that? On a somewhat related note, would you still get 3 OKs if, say, i intentionally wired one pair of input channels out of phase or did not include a pair of channels which was necessary to generate a full range signal?

5. I remember getting 3 OKs the first time with volume at 46. All subsequent attempts at input setup got me the 3 OKs at volume 39 and 40. Maximum is 60. At volumes 38 and below got me a level low, and 41 and above, level high. I remember getting lots of signal noisy messages too at random volume levels (mostly at the high end, above 40). I never got a signal noisy at 39, or 40 though. At those volumes, i always got the 3 OKs. I ran input setup with volume at 39 the first couple of times, then at 40 at every attempt thereafter. Results were identical regardless of the volume i chose


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## 14642 (May 19, 2008)

blackreplica said:


> Oh dear its already 1am where i am and i gotta get to bed. Will check up this thread once i wake up later today before i head back to my installer. in the meantime, if there are any suggestions as to what to do in addition to what has been advised already, post it here and i'll give it a shot. hell, i'll give anything a shot.
> 
> Andy, if you have any idea what i should do to the JR1 connector, let me know with the specifics and i'll get my installer to do it. Just post here and i'll get it done later today


Oh, sorry. Disconnectthat JR1 connector. That's the connector for the microphone. That will kill the noise cancellation and should fix the feedback.


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> Oh, sorry. Disconnectthat JR1 connector. That's the connector for the microphone. That will kill the noise cancellation and should fix the feedback.


Consider that done. Will be my first order of business once i get back to the shop tomorrow. What a strange place to put a microphone harness...did they put the mic in the roof or something??? I never even knew my stereo had some sort of noise cancelling programming going on

Hopefully this works. Will post the results of the harness disconnect ASAP. In the meantime if anything springs to mind which you think may help, i'm all ears. I cant thank you enough for the help you and Adam have given me so far. You guys have some pretty insane vehicle-specific knowledge


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## t3sn4f2 (Jan 3, 2007)

Andy Wehmeyer said:


> I feel pretty sure that there are a couple of issues here. One may be that the sweeps are too loud during calibration. The other is most likely the factory active noise cancellation, which has no idea what to do when an additional EQ is placed in the system. The diagram below is for a 2009 IS250, but a left hand drive version. Look for the connector labeled JR1 (I'll bet it's on the other side in your car). If your car isn't 2009, and you don't find this connector, please let me know the year of your car and I'll go do some more research.



Are there any others in the car. The new accord has two, one in the front map light area and one in the rear IIRC.

Also, what is JR2. Seems to go to the same mic?


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## AdamS (Dec 22, 2009)

blackreplica said:


> 4. OK as far as i know: I instructed my installer to only use all the front speaker outputs + sub from the factory amp to be connected to the MS-8. Channel 1 + 2 of the MS-8 is getting the signal from the Front channel mid/high of the Levinson amp (the levinson splits this output via passive crossover for the tweeter/mid combo, according to my installer). Channel 3 + 4 gets the signal from the Levinson Front channel midbass (which is dedicated). The remaining signal is tapped from the subwoofer output of the levinson amp which is wired to channel 8 of the MS-8. All are high level inputs tapped from the speaker outputs of the levinson amp.


Sounds like you are connected properly.

1. ensure that surround processing (on the Levinson system) is disabled. If Logic7/Mark Levinson Surround is running on your HU, you will have problems.
2. ensure the mic(s) are disconnected
3. if these two don't totally fix the problem, try disconnecting the sub input. 
In some units, the sub level is so far away from the mid/tweets that the UnEQ can't totally compensate. Disconnecting the sub will use the mids to reconstruct the sub signal. This works well in most cars if the OE sub/mid crossover is less than 100 Hz or so. 
OR
The other option is to use the Bass control on your head unit and pull down the bass control by several dB (and pull up the mid/highs controls by several dB) to pre-EQ the levels a little bit before UnEQ processing. 

In my stock IS250 system, the sub is +36 dB above the mids.

And, MS-8 should handle the polarities going into MS-8 from the head unit, even if they are flipped.


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## 14642 (May 19, 2008)

Hey, one more thing. JR1 includes the three wires in the diagram below (follow the ones that lead to the microphone), but it may contain others. I can't find any others, though. If there are a bunch of wires in that harness, try to only disconnect these three: Blue, yellw and brown. Disconnecting only blue might do it.


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## blackreplica (Mar 14, 2005)

Hi again guys,

First of all, sorry for posting here a day late. Wasnt able to spend some time in front of the computer yesterday

I paid a second visit to my installer on friday to see if we could give all your suggestions a shot and find the source of the problem. 

Andy, we first tried to find the JR1 harness. It was where i the diagram says it was, on the left A Pillar. There wasnt a harness of any kind on the right side. Unfortunately there were actually 2 blue wires, in addition to the yellow and brown, and we disconnected them all but the feedback issue did not change at all, it was still there. In a moment of desperation, i took a chance and asked him to pull out the entire harness. Still feedbacked. If there is a mic in the system, i suspect the wire must be somewhere else.

After that we did a bit of our own troubleshooting. 

AdamS, we also tried your suggestion of using only the front channel levinson amplifier outputs, and removing the sub channel. It was still able to output what sounded to me like a full range signal ( + the 3 OKs). But it did not solve the feedback issue

Other strange (but perhaps useful things we found out)

If we use the levinson speaker outputs, hooked it up to a high-low converter and used the JBL MS-8 RCA inputs instead of the high level inputs, there was still feedback

However, this is where things get interesting. When we use the MS-8 AUX-in connection, the feedback completely goes away! The head unit signal is clean. I'm not sure what to make of it

We tried making a few calls asking if anyone knew where we could find the factory microphone location, but no one had any idea

In the end we gave up and wired things back the way they were at the beginning. I'm using my iphone hooked up to the MS-8 aux-in as a temporary make-do. Did a bit of tweaking with levels and EQ and am really impressed with the sound.

Any more ideas i could try?


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## blackreplica (Mar 14, 2005)

Not exactly sure if this is useful but here is a picture of the harness. You can clearly see the 2 blue wires. This was the only harness (on the left) we saw from both pillars.


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## 14642 (May 19, 2008)

That's definitely the harness. the microphone is located in the dome light assembly. It's also the cellphone microphone, so you'll lose factory integration of your phone when this is disconnected.

Disconnect the rear speakers from the Levinson amp. Fading to the front will eliminate the audio that goes to the rear speakers, but any noise cancellation signal will still be present. Finally, if when you hook the output of the factory system to the aux input and it sounds great, try hooking that same signal to inputs 1 and 2 and choose "skip input setup" in the menu.

I suggest connecting the rear speakers to MS-8's output. Having the rears play when you use L7 will sound better. 

In any case, I can help you get this fixed while I'm there, if you can wait that long (another week and a half). Marcus (our country manager) and I can meet you at your installer's shop if you'd like.


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## t3sn4f2 (Jan 3, 2007)

Andy, for future reference for other cars that might have this issue and have it resolved by skipping the input setup on the main input option. Will the only compromise be that the AUX input will then be mis-calibrated since the MS-8 calibrated off an altered OEM signal?


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## blackreplica (Mar 14, 2005)

Hi again Andy,

The trouble is, when i disconnected the entire harness, the feedback did not go away. What do you suggest i do with the harness?

I have no cellphone integration with my stereo so i dont mind losing that feature

I will try to do what you suggest of disconnecting the rear speakers from the levinson amp.

I would love to try rears and sides with Logic 7 but unfortunately im pretty much all out of channels unless i somehow use passives with my 3 way fronts.

Will also try skipping input setup the next time round and see how that goes

Andy, you and Marcus are most welcome to come visit me at my installer. I already gave my installer a heads up that i might be swinging by with you guys on the 28th. Hopefully we can resolve the problem before then, but if not, thats fine as well. I'm not in a hurry as long as i can use the tunes on my phone for the time being


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## 14642 (May 19, 2008)

No, if you choose "Skip input setup", the difference between the Aux and the HU input will be only the factory EQ in the head (if any). MS-8 generates the signals for acoustic calibration, so the head unit's frequency response has nothing to do with that.


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## blackreplica (Mar 14, 2005)

So, just to confirm, you want me to try hooking up the factory speaker outs to the high level MS-8 inputs (i.e the way i had it originally wired up) and just select skip input setup?

How about the harness? which wire exactly should i disconnect, and should i run skip input setup/calibration as well after that?

P.S Not sure if this helps but i distinctly recall losing the dome light when i disconnected the thicker blue wire. I cant remember if the same thing happened with the thinner blue wire


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## 14642 (May 19, 2008)

blackreplica said:


> Hi again Andy,
> 
> The trouble is, when i disconnected the entire harness, the feedback did not go away. What do you suggest i do with the harness?
> 
> ...


Here's an easy way to determine whether the car's mic is causing a problem or to see ifit's even involved in the problem. While the system is feeding back, cover the mic with your hand to see if anything changes. It's located in the dome light assembly overhead. Look for a little grille or a few slits in the plastic. 

Also, MS-8's microphone is completely unplugged, right? 

One more question: I think I read that this problem is worse when the car is moving. Is that correct? Is that the only time it feeds back or also when the car is stationary?


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## 14642 (May 19, 2008)

blackreplica said:


> So, just to confirm, you want me to try hooking up the factory speaker outs to the high level MS-8 inputs (i.e the way i had it originally wired up) and just select skip input setup?
> 
> How about the harness? which wire exactly should i disconnect, and should i run skip input setup/calibration as well after that?
> 
> P.S Not sure if this helps but i distinctly recall losing the dome light when i disconnected the thicker blue wire. I cant remember if the same thing happened with the thinner blue wire


The thinner blue wire is power to the electret microphone. Before you go reconnecting everything, how did you connect the output of the levinson amp to the aux input?


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> Here's an easy way to determine whether the car's mic is causing a problem or to see ifit's even involved in the problem. While the system is feeding back, cover the mic with your hand to see if anything changes. It's located in the dome light assembly overhead. Look for a little grille or a few slits in the plastic.
> 
> Also, MS-8's microphone is completely unplugged, right?
> 
> One more question: I think I read that this problem is worse when the car is moving. Is that correct? Is that the only time it feeds back or also when the car is stationary?


Ok i will try taping up all the holes on the dome assembly and see what happens

Yes the MS-8 mic is always disconnected. I am using an extension cable though

yes, the problem is definitely worse when driving.Plus more problems with channels cutting in and out and what sounds like phase shifting constantly However the problem is still present when the car is stationary. But when stationary its mostly just feedback. Occasional channel cutting in and out (with some crackling) at very high volume levels


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## t3sn4f2 (Jan 3, 2007)

Andy Wehmeyer said:


> No, if you choose "Skip input setup", *the difference between the Aux and the HU input will be only the factory EQ in the head (if any).* MS-8 generates the signals for acoustic calibration, so the head unit's frequency response has nothing to do with that.


Yup, that's what I meant to ask.


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> The thinner blue wire is power to the electret microphone. Before you go reconnecting everything, how did you connect the output of the levinson amp to the aux input?


I've already wired everything back to the way it originally was before, including all wires in the harness, unfortunately. When i revisit the installer, i will have the thinner blue wire disconnected. How about the brown and yellow? Should i disconnect those as well?

We connected the Levinson amp to the aux input by taking the high frequency speaker wires, using a hi-low converter, and plugging the RCAs to the AUX. Obviously there was a loss of low frequency information, but there was no feedback or crackling.


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## 14642 (May 19, 2008)

OK. One last question. Does the car have navigation? If it does, also look for some little slits (another microphone) in the area around the display screen. 

Sorry about all of this back and forth. The diagram of the car I'm working with is like a Rube Goldberg drawing...


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## 14642 (May 19, 2008)

blackreplica said:


> I've already wired everything back to the way it originally was before, including all wires in the harness, unfortunately. When i revisit the installer, i will have the thinner blue wire disconnected. How about the brown and yellow? Should i disconnect those as well?
> 
> We connected the Levinson amp to the aux input by taking the high frequency speaker wires, using a hi-low converter, and plugging the RCAs to the AUX. Obviously there was a loss of low frequency information, but there was no feedback or crackling.


OK. This is enough to confirm for me that the problem is active noise cancellation in the factory system. There would be little or no frequency response correction at high frequencies. It would be in the lower midrange and the bass frequencies. This is a pain in the ass, but it's good news. at least we're begining to narrow down the problem.

The brown and yellw wires are the signal wires from the mic. The blue one provides power to the electret, which inreases its sensitivity. Just put your hand over the mic to see if the problem changes. Also, look for another mic near the display. I also see some wires between the display andthe radio that indicate "MIC+ and MIC-", but I can't confirm the existence of a second mic because it may be integral to that entire assembly.


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> OK. One last question. Does the car have navigation? If it does, also look for some little slits (another microphone) in the area around the display screen.
> 
> Sorry about all of this back and forth. The diagram of the car I'm working with is like a Rube Goldberg drawing...


Andy, no problem at all. shoot me any question you want, i am happy to try and answer them

Negative sir, i do not have nav. Singapore IS250s do not have a factory nav option even with luxury spec (the privilege is reserved for the GS series and above) . My system is the non-nav premium Mark Levinson


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## blackreplica (Mar 14, 2005)

Andy Wehmeyer said:


> OK. This is enough to confirm for me that the problem is active noise cancellation in the factory system. There would be little or no frequency response correction at high frequencies. It would be in the lower midrange and the bass frequencies. This is a pain in the ass, but it's good news. at least we're begining to narrow down the problem.
> 
> The brown and yellw wires are the signal wires from the mic. The blue one provides power to the electret, which inreases its sensitivity. Just put your hand over the mic to see if the problem changes. Also, look for another mic near the display. I also see some wires between the display andthe radio that indicate "MIC+ and MIC-", but I can't confirm the existence of a second mic because it may be integral to that entire assembly.


Ok will do. I'm gonna take some pictures of the dome assembly and factory HU as well so you can see if you think there is a possible mic hidden somewhere. I'll also try taping a towel over the entire dome assembly and see if the feedback reduces.

My next trip to the installer should be on monday. If you have any specific instructions for me to try when i am there (in addition to what you've already asked me to do), let me know. thanks

Standby for the results on blocking the mic


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## blackreplica (Mar 14, 2005)

Just a quick update, i only see 2 holes on the dome panel near the light switches. Tried covering them up with a thick cloth and tried the head unit again. There was still feedback, and there was no difference in the amount of it whether i covered the holes up or not. Inspected the head unit but didnt see any holes where a mic could have been mounted. If it helps, ill take some pictures of the dome and head unit and upload them on here tomorrow


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## blackreplica (Mar 14, 2005)

Just to give a quick update. I definitely cant hear a reduction in the feedback by blocking what appears to be the mic holes on the dome panel. Ive included pictures of the dome and head unit face here. Other than those two holes at the top, i still dont see any other place where a mic could have been mounted. Even completely disconnecting the entire jr1 harness and all associated wires did not reduce the feedback. AdamS has asked me to try running a calibeation by using my iphone wired into the levinson head unit aux input to see if that works. Ill have to rip the ms-8 cd to .wav before i get round to that. Is there anything left to try? Ill also attempt to unwire the rears from the levinson amp one of these days

Pics:
on Flickr - Photo Sharing!

on Flickr - Photo Sharing!


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## glidn (Apr 21, 2007)

maybe this is a little bit out of left field. What are the chances that you damaged the high level inputs of your MS-8? By running from the amp to the ms-8 to your new amps/or speakers? I'm pretty sure they dont want anything about around a few mV's? if I can remember correctly.

Can you temporarily plug in a simple radio and use it's speaker level outputs and also try the RCA outputs? This way you can eliminate the speaker level/RCA input's to be faulty.

I would start there.

Honestly I would have thought best to either run from radio to MS-8 to Factory amp to speakers. OR . factory radio to MS-8 to aftermarket speakers?

By doing these above steps will straight away prove there are no issue's with the MS-8 currently then continue down the road as mentioned above.

By doing this even if it does not drop the feedback than you know 100% it's the factory radio or even possibly the amp.


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## blackreplica (Mar 14, 2005)

glidn said:


> maybe this is a little bit out of left field. What are the chances that you damaged the high level inputs of your MS-8? By running from the amp to the ms-8 to your new amps/or speakers? I'm pretty sure they dont want anything about around a few mV's? if I can remember correctly.
> 
> Can you temporarily plug in a simple radio and use it's speaker level outputs and also try the RCA outputs? This way you can eliminate the speaker level/RCA input's to be faulty.
> 
> ...


I suppose its possible, but when the rca inputs were used instead of hi-level, there was still feedback. Unless both types of inputs are faulty. Using the ms-8 aux inputs however, the problem disappears. But from the way the feedback sounds, it really does sound like there is a mic somewhere screwing around with the system. maybe i should try recording the sound, it might help with the troubleshooting.


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## 14642 (May 19, 2008)

OK. I don't have a diagram for the Singapore (Asia) version of this car with Levinson and without Nav. I'll try a different angle for finding out what's going on. Hopefully I can get ahold of these folks today. Please stay tuned.


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## blackreplica (Mar 14, 2005)

Roger sir. In the meantime if i can, i will revisit my installer, disconnect the blue, brown, and yellow wire on the jr1 harness, disconnect the rear speakers, and run input setup + calibration using the .wav rip of the ms-8 on my iphone using the levinson head unit aux in as per AdamS' recommendation. Thats about the best i can do at this stage. Will keep a lookout for any further info on this thread. Thanks for everyone's contribution so far!


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## blackreplica (Mar 14, 2005)

double post


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## blackreplica (Mar 14, 2005)

Ok this is weird. Not sure if it helps any, but for the sake of information in case someone else has the same problem, i'll post it here

It started when i attempted to run a new input setup/calibration following AdamS' advice to use my iphone hooked up to the Levinson Head Unit Aux-in. 

Imagine my surprise when the calibration was complete and the feedback was completely eliminated.

I was happy at first until i realised this: I had mistakenly left the Levinson 'Surround' function enabled in Aux Mode (which i used my iphone on) on the head unit (it had been correctly turned off in CD mode, but i forgot that the levinson HU remembers your audio settings based on the mode you are in), and run the setup with it switched on

When i re-ran setup + cal with it switched off....surprise surprise...the feedback was back, in full force. Doesnt matter whether i use the iphone or the head unit to run setup. 

Basically: If levinson 'surround' is turned on, and setup is run, feedback disappears, provided surround is not switched off again later on. The sound is still not 100% right though (there is something funny going on still with the way the MS-8 is steering some of the sound effects in the music, but its relatively minor and something to do with the surround logic on the Levinson probably). If i turn 'surround' on the Levinson off later, the sound collapses and everything sounds like its playing in a cave. 

I dont know much about the levinson surround option except that it uses a center channel, much like logic 7 on the ms-8, and sounded much better (with the stock system at least).


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## 14642 (May 19, 2008)

Interesting. I'm not entirely sure what to make of this. Please PM me the address of your installer in singapore and let's arrange a time to meet next Wednesday. We'll get all of this straightened out then. I'm currently collecting some information form our OEM group.


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## blackreplica (Mar 14, 2005)

PM sent. I'll let my car and sound system take a break while I wait for you to arrive and take a look at things. 

Not sure if anyone else with an IS250 is following this thread, but if so, i promise to post the solution (if one emerges) in this thread for future reference

Thanks again Andy, and see you soon


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## Diffeomorphism (Aug 14, 2010)

Was the issue identified?


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## A-Ron (Feb 12, 2010)

I'd like to know as well since I'm having a very similar problem in my 09 GMC Sierra! Using AUX sounds amazing, using the headunit sounds like ass! Damn OEM!!


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## AdamS (Dec 22, 2009)

A-Ron said:


> I'd like to know as well since I'm having a very similar problem in my 09 GMC Sierra! Using AUX sounds amazing, using the headunit sounds like ass! Damn OEM!!


I've been working with A-Ron on this, and it is largely resolved.

Here's a summary:

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

09 GMC Sierra stock
UnEQ/Signal Summing using Rear Channels (very similar to fronts, but no signaling)
Sample Rate is .5% too fast. This is within the range of correction.

The UnEQ/Signal Summing needed some extra computational complexity, so I added it. As of now, it is only a beta release. 

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


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## A-Ron (Feb 12, 2010)

Adam,
I can't thank you enough for all your help!!


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