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Discussion Starter · #1 ·
Need a little help here. I just finished installing my audio system and it sounds great however whenever I put the key in the ignition and move it to the on position a loud thump occurs. When I say thump I mean one quick base tone and I just tested it and its only happening on the subwoofer.
How do I fix this and what is causing this problem.
thanks
Adam
 

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my speakers do the same thing whenever you turn the ignition off, nothing happens when i turn it on.
 

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okay i was gonna say u should haev searched first, but it took me quite a while to find the topic on this so im not even gonna bother...but this guy had the same problem, HERE are some of our responses, hope it helps
 

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Discussion Starter · #4 ·
well I read that post but it really didnt help. I mean I have a great ground connection and the remote wire doesnt seem to be spiking when the radio is turned on. I am using the remote wire comming from the HU Alpine CDA-9847 and I have it running to two amps but only the Alpine MDR-500 is thumping like that. Should I connect the accesory/remote wire to someting else?
thanks
Adam
 

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Discussion Starter · #6 ·
Well it seems like it is a power surge or something. The RCA wires are run on the other side of the car and the ground is a 4AWG about 12 inches away bolted to sanded bare metal.
When the car comes on all of the guages go up then down and whne they go down thats when the radio turns and as soon as the radio turns on the loud tump happens. I posted my wireing diagram and everyone including you said it looked just fine.
Oh well, just post if you have any ideas about whats going on.
Adam
 

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Discussion Starter · #7 ·
So I re-grounded everything and still the same thing is happening. I pulled the deck out and monitored the voltage of the Remote Turn-on as I turned the key to the ON position and basically it registers about 9-9.8V while the gauges are all moving up and comming back down, then THUMP and the Remote Turn on registers 12.6v right after(or mayber during) the thump.




Ok I just thought of something. I have my amps mounted behind the back panels (both sides). I had to fabricate a bracket system to hold them. The brackets are all metal and they are screwed into the cars metal and they are connected to the metal amp. Am I just an idiot. You cant do this right? I shouldnt have the external pieces of the amp touching metal right?
 

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Originally posted by adambeazley@Aug 7 2005, 09:29 PM
So I re-grounded everything and still the same thing is happening. I pulled the deck out and monitored the voltage of the Remote Turn-on as I turned the key to the ON position and basically it registers about 9-9.8V while the gauges are all moving up and comming back down, then THUMP and the Remote Turn on registers 12.6v right after(or mayber during)  the thump.




Ok I just thought of something. I have my amps mounted behind the back panels (both sides). I had to fabricate a bracket system to hold them. The brackets are all metal and they are screwed into the cars metal and they are connected to the metal amp. Am I just an idiot. You cant do this right? I shouldnt have the external pieces of the amp touching metal right?
Another person with back panel mounting... I couldn't get my brackets right.. I need pictures!

Anyways...

I don't think the amplifier components are grounded to the amp chassis and actually just through the wire, so this shouldn't be an issue? Right? I mean RIGHT! Err..

Thats my guess anyways.

As for the thumping... hmm.. that reminds of the time I tried to use the ignition wire as my remote wire and that induced a thump and noise. Unfriendly remote wire? Bad RCAs?

I had this annoying thing with my old Kenwood Excelon deck... the stupid thing shutoff the amp when you switched your source and I'd get the thump sometimes. Nice sounding deck though. Almost sounds like the amp is on and then the amp shuts off and back on again within a split second.

I don't know.. I've been out in the heat for the past 2 1/2 days finishing my system (one of the spx-177r mids are blown gah!) and not getting my mrv-f345 mounted behind the drivers side rear panel (grrr!!!). Oh well.. good luck!
 

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adam, very interesting problem, and yes your wiring diagram looked fine. Are you sure you are connected to the remote turn on(blue w/white for most)? It is time to just start trying other options. You redid the ground so you can check that off your list, maybe try power antenna lead instead of remote turn on. I wouldn't think that the brackets attached to metal would matter much, but it is always something else to look at. Is your head unit grounded to somewhere in the dash? Hard telling exactly what is wrong, time to just go through the wiring piece by piece.
 

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Discussion Starter · #10 ·
Well I regrounded the head unit as well. I grounded it by itself to bare metal. When the system is on anp playing I am not gettig any noise, it sounds perfect. (aside from initial thump)
My next thing to do tonight is to connect the amps to the power antenna wire instread of the remote turn on. We will see if that works. Also I downloaded a pdf on how to setup that MRD-M500 amp with all those digital controls. Im used to the old school amps with the gain turn knob and this one is a bit more complicated so I might have the settings wrong. Considering I bought this used and I messed with the settings a bit before reading up on it, that might have something to do with it. Well we will see what happens.
Regardless, I must put this car back together tonight because we are going out of town.

Also, if anyone knows which wire the KEYSENSE wire please let me know. My alarm is working except for the remote start. I have a feeling I got the wrong wire to bypass the keysense. The DirectWire diagram says its the white wire in the ignition harness, however there are three different white wires so Im stuck doing the old "trial and error."

anyway thanks for all of the help.
Adam
 

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i dont think the power antenna wire will solve your problem except to maybe help determine if the problem IS the remote wire, becasue as far as i know, in alpine decks the power antenna wire is only on when the stereo is selected to radio, so when u switch your source to cd, it willl turn off, but by doing this you may determine that your remtoe wire is bad.

based on hwat i was reading from ur post i think it must be either your amp, something faulty. Or the rca's....besides that u have a text book install, so keep us up to date....
 

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just read ur last post and u mentioned ur amp, i doubt its faulty, but from what people were saying is that these amps have a delay setting that willallow it to power up a few seconds after everything else in the car, that might be the something to look into
 

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^^^Yes bingo, thanks for letting me pull my head out of my ass.....the alpine head units have built in features that allow you to adjust the delay for the turn on, adding another second or two should solve your problem and then you dont have to change any wiring.
 

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Discussion Starter · #14 ·
ok well here is whats goig on. Basically The fact that the amps are mounted to metal isnt making any difference. I took them off of the mounts and put tem on the carpet and everything was still happening. I did find out that the MRD-M500 has a turn on delay and when I set that to 2 seconds the thump in the subwoofer stops. Now the amp running the front component set is an old alpine and it doenst have any type of delay. So I serched around the internet and lerned how to make a turn on delay out of a diode and a capacitor.

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Quick tutorial:
Get a 1N4004 diode (radio shack) its a 1 Amp diode. Next get a Capacitor (polorized electrolytic) with a value of 100 - 1000uf (micro farrads) and rated for at least 16V. Now depending on how long you want the delay to be just follow this:
1 second delay = 100uf capacitor
2 second delay = 200uf capacitor
3 second delay = 300uf capasitor
ect........
Now basically you cut your remote wire and connect the Anode end to the side leading to your radio and connect the cathode end (identified by polarity band) to the side leading to your amps. Now get that capacitor and connect the positive end of the capacitor to the Cathode end (marked with colored band)of the diode and connect the negative end of the capacitor to the vehicle chasis (ground it).
And thats it you now have a turn on delay- the energy is stored in the capacitor until its full and then the overflow electricity goes to the amp and this is what causes the brief delay.
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Ok now back to what I was saying. I used that turn on delay and it is working. Every now and then I will get the thump, but i think thats because I need a larger capacitor. Anyway I didnt realise that the Alpine head unit has a turn on delay function built in. I will have to read up on that and turn it on. Anyway thannks for all of the help Im just glad im done with that project it took me 8 days to sound proof, audio setup, remote start alarm, wireless bluetooth car phone setup and the custom box and Im still not finished.
Well I am for now and Im going on a vacation so peace out people.
Adam
 

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Discussion Starter · #15 ·
Ok I just looked through my owners manual and I am not seeing anything about a turn on delay on my head unit. Are you sure that the Alpine CDA-9847 has that option?
Does anyone know? If so please educate me on how to turn that option on.
thanks
Adam
 

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i dont think that head unit has a delay...but its good to see that u have a handle on the situation
 
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