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Discussion Starter · #1 ·
Okay guys, I'm at a complete loss as to what the flying **** is going on here. I have a Kenwood KAC-8104D Class D amplifier hooked up to two, MTX Roadthunder RT-10 Subwoofers in parallel. Driving home two days ago, music not even turned all the way up (was 25 on the HU) and then "shrrrrrt" (for like a half a second, kind of like a scratch sound.), bass cuts out for like 2 seconds and comes back on. I got home, examined everything, didn't find any issues at all. I did a full running test for anything sounding off or not right. Found nothing. Drove home yesterday the whole way with the bass pounding, no problems at all. Today, bought some Dynamat at Circuit City's GOFB sale. Had my the HU playing "Beam Me Up" for like 30min at 10 volume (not nearly loud but it worked enough for me to find the places to Dynamat. BTW, those darn sedan trunk vents....grrrrrrr!! Found out they pretty much are the problem.) But anyways, no problems at all. Get everything done, decided to go around the block for a test run. I have the HU at 20 volume. 30 seconds into my trip, same sound again, no bass AT ALL this time. The subs completely cut. So now I'm like WTF. Turn off HU, turn back on, still nothing. I get home, turn my car off, turn it back on, bass comes back :evil: Thinking I blew out my subs, I unscrewed them out of my box, did a full examination, and I HIGHLY doubt I blew them out. I have had them POINDING sometimes and yet they look new. There's no scratching when I push on the center cone or anything. Spider coil looks fine too. (Picture of Subwoofer, Spider Coil on Right Sub, Spide Coil on Left Sub.)

So.....

Amplifier. Pushes out 500rms to 2, 200rms subs. 100w over the rms. To my knowledge that is okay though. I have my speaker level input adjuster turned down a little bit though just in case. However, perhaps the amplifier driver went bad? Prior to this I just had the bass cutting out at random times, only ever happened twice though, then it went away for like a week, and came back as this.

The subs don't sound like there is a problem. They sound 100% fine. I really, really doubt this is the subs. Could it be the amplifier?

Any ideas?
-360
 

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[quote author=Mizzle link=topic=134350.msg2888354#msg2888354 date=1232843284]
Sounds like a loose/poor ground.
[/quote]

+1. I've had weird stuff happen due to a dirty ground (including having my headunit freak out, even though the bad ground was for the sub in the trunk).
 

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I'd say make sure all connections to the amp are good, maybe just pull and clean those and then do the ground too.
 

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Check your amp next time it cuts out, pull over and make sure its on and not in 'protective' mode. I have used a few amps and had similar problems I would replace the amp and all was fine again.

the setup I have now works no problem, but when I drove to Florida the last hour it stats to go to protective mode for a couple seconds. no idea I guess its tired after 8hours of driving... but I know thats the only time so no ground etc.. anyhow I believe its heat related don't know if its a problem your getting but like i say, just pull over when it dies and check it out, carry a multimeter around if need be so you can test power/ground is fine and amps running etc.
 

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Discussion Starter · #6 ·
Thanks for the replies guys! I retightened my ground wire yet again and so far I haven't had any and issues. It seem to be working fine now although I think I'm going to need to find a different place to ground my amp because I am fearing that I am striping my seat bolt by taking it in and out so much. :shock:

When the bass cut before I couldn't get my passenger seat froward enough to see if the amp was still on (since it's under that seat.) so I really couldn't tell you the status of it when it happened. It did appear to be fine when I got home though. There was no protective mode on and everything was lit and working. Except of course the fact there was no power to the subs. I'm thinking it may have been the ground because the bolt wasn't necessarily loose but it wasn't tight either. I'm not really sure how that happened.

But for right now everything seems fine. Thanks again guys!
 

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I would say don't mount it to the seat. Find a bolt to the chassis or frame of the car. It also doesn't help that The frame of the seat I think is painted black. If it is and you're going to keep it grounded there, strip the paint off of where you have the ground connected.
 

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yep... thats your problem....the old grounding it to the seat bolt mistake... the problem there is that that plate the bolt goes into sits on top of painted metal....clean a spot free of paint on the chasis or frame and ground it there.....remember!!!!!! make sure the metals shinny!!!!!lol
 
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