Help! JBL MS-8 turn off thud!

[dillypo]

I'm hoping someone here can help me.

So before this last weekend I had two alpine amps a pdx-m6 for subs and pdx-f4 for the 6" doors and 6x9" rears. I couldn't get the car to sound how I wanted so got myself an ms-8 and installed it this last weekend. I haven't played with it to much yet but the auto-config gets it way better than I was able to do without it. Probably 80-90% there. Anyway after I installed it I noticed when it turns off I now get a loud thud.

I've been experimenting for a few days trying to get it to go away. I double checked and confirmed that the remote on/off is wired up correctly. It goes from the car -> ms-8 -> amps. I tried playing with the off delay but that doesn't seem to be the issue. I think that is supposed to help if its the amps themselves making the noise and I do not believe this is the case for a few reasons. First they didn't do it before. Maybe a very barely audible tap noise but this is a full loud "BUMP". Second while playing with the gains on the amps vs the volume on the ms-8 (more on this in a second) when I had the gains up pretty high on the amps and the turn off delay set to 5 seconds on the ms-8 I heard two turn off noises. First the loud thump from the ms-8 and then 5 seconds later the soft "tap". The second would be the amps, so to me that confirms that its the ms-8 sending out this signal. It also happens the second the ms-8's screen turns off regardless of the turn off delay.

I also noticed the volume of the thump is directly related to the system volume of the ms-8. The higher it is, the louder the thump, and if I mute it before turning off the car and opening the door there is no thump at all. I don't feel that I should have to mute it everytime. I was trying to compensate for this by turning the gains higher and higher on the amps so I could have the volume lower on the jbl but it gets to a point with high gains where a little bit of noise becomes audiable and the thud still isn't quiet enough for me to live with it. So I reset them back down.

The headunit is the factory as I want to maintain the stock look of the car.

The thump appears to coming from all channels. It is quite startling loud but I don't think its damaging to the speakers. Its not louder than I comfortably play loud music and its not a burst of static or short pop but a thud like a loud bass drum hit. I don't think I'm willing to just live with though.

Anyone have some ideas for whats causing this and more importantly how to fix it?

[CamaroGeek]

Metra has a new product called the Trigger (imaginative name, yes?) which does about 20 different things for car audio - turn on delay, turn off delay, RAP, etc. One of the modes is specifically for GMLAN Amp Turn On. This will solve your problem. You can get them from sonicelectronix.com, search for the Axxess Trigger.

[dillypo]

I don't see how this will help. The sound happens when I turn it off not on and it's a signal coming from the ms-8 not the amps.

[CamaroGeek]

The problem is the radio, not the MS-8. The radio's outputs drop before the turn-on line does, and that's when you get the pop. There is a mute line from the radio that needs to be used, and the Trigger does that. If you put the Trigger between the radio and the MS-8, the MS-8's turn-on line will be dropped before the pop happens.

[baskethead]

Tbone587 sent me the following
"If you are connected to the turn on wire through the ******** harness you will get a turn off thump. Connect your wire to the green wire at the cig plug connector in the center console."
worked like a charm.
Greg

[CamaroGeek]

That should work as well. You will lose your "key in" or "lights left on" chimes, but that's probably a minor point. Unless you leave your lights on....

[Agent WD-40]

Originally Posted by CamaroGeek

Metra has a new product called the Trigger (imaginative name, yes?) which does about 20 different things for car audio - turn on delay, turn off delay, RAP, etc. One of the modes is specifically for GMLAN Amp Turn On. This will solve your problem. You can get them from sonicelectronix.com, search for the Axxess Trigger.

I didn't see this on SonicElectronix. Do you have a link?

[CamaroGeek]

http://www.sonicelectronix.com/item_40417_Axxess-TRIGGER.html<br>

[dillypo]

Well I did some tests today to verify what you guys said (that its the head unit). I then started looking around for another 12v source. My cig plug connector didn't have a green wire, just a red and black. For now I went ahead and tied into the cig plug to use as an on/off wire and that seems to be working well.

For anyone else who stumbles upon this, there are a few downsides to doing it this way. As mentioned above you do lose the warning chimes that tell you if you left the lights on and in addition to that you also lose the ability to turn on the radio without the key. By that I mean sit in your car with the head unit off. Then push the power button (volume). The radio comes on and starts playing but if you have it tied into the circuit the cig lighter is in, the amps won't come on. I think this is part of the aux circuit so they only come on when the aux power is on.

Thanks for everyones help!

[The 2010 Sin]

You just need to set ur turn off relay on the MS-8. Mine used to do it until we made the simple adjustment

[dillypo]

It's not the turn off delay. Not to be impatient but if you read the initial post it'll explain why its not that.

[The 2010 Sin]

I didnt have to sacrifice the use of chimes, cigarette lighters or any other power source with my setup.. if you are let me know and i'll get the answer: here's the questions i'd have if you want to make it work without the sacrifice of all of your factory setup.


Okay.. Sorry. I reread what you have posted and let me ask you a few questions. I've had the MS-8 since day one. I am a team member and competitor for Team JBL. I'll get the answers for you if I dont already have them.

What equipment is your MS-8 processing. Are you using JBL Gto amps MS amps or another brand? Aftermarket headunit?

Also, When you did your initial setup with your headset mics, what was the gain on the MS-8 and the volume on your headunit set to during process? ( This will and can play a huge part in how the entire system is calibrated and how it will perform as far as highs, mids, lows and alignment )

Have you adjusted your amplifiers after having done the calibration trying to correct the issue without going back and recalibrating the system using the headset?

If you can get me those answers I'll call Jeremy or Gary Biggs and have an answer back to you in just a short bit.

We can figure this out.. Im on a stock headunit and I took first at Iasca nationals in SQ with this bad boy! lets get yours doing what it should!!!

Zach

[Hooper]

Hi Camarens...
I have read this thread and done as much online research as I can to no avail. I have 2 aftermarket amps, speakers and sub. Using the stock head unit. I had no turn off thump before adding the MS8, now I do. I have played with the delay - turned off, 2 secs, and 5 secs. No success. I don;t want to lose my factory accessory operations. there has to be a solution here. Does the trigger affect anything else in the system? Any help is appreciated. Thanks...

[ppiamp]