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Discussion Starter #1
This is going to be a length post and I'm just going to start from the beginning. I recently bought some LPG 25NFA tweeters, Seas G18rnx/p from npdang and solen, and some dayton audio 3khz crossovers for my truck. Before this I had some Infinity Kappa 572.5cf powered off my Kicker 800.4. I decided to go passive with the new setup because I could bridge the Kicker amp which is rated at 400 RMS @ 4 ohms, to where it could get around 200 @ 8 ohms. I got the tweeters before the Seas, so I figured I'd go ahead and install them. Since the crossover allows you to be able to use either an 8 ohm driver or a 4 ohm driver as the mid, this seemed like a good idea to do.

I install the crossovers and wire the Infinity Mid to the woofer part of the crossover, and the tweeter to the LPGs. It played fine, but their was an underlying hiss sound that you could hear at low volume with the engine running. It wasn't too bad, but little did I know this would get a lot worse.

A few weeks pass and I receive my Seas in the mail. As soon as I can get home to install them, I make my mounting brackets, get all the modeling clay and such to seal it off and install them in the doors. I switch the crossovers to the 8 ohm setting and fire it up. Their is now a very loud wine that corresponds to the engine's RPM's which is engine noise. When I put the car in the on position without the engine running, it makes the same underlying hiss it did before, except it's a lot louder. Also, whenever I make volume adjustments, or change EQ settings, the HPF, or turn the head unit off, it will make very loud clicking and popping sounds that sound really really bad, as if the speaker was getting damaged almost.

I figured I should just troubleshoot this going through the obvious stages so I begin. My first thinking is that the crossover is picking up some engine noise from underneath the dash where I mounted the left one (the right one is in the right kick panel away from electrical devices and wiring). I move the crossover right next to the amp and it still gives me the same problem. My next line of thinking is that the RCA's may of gone bad or something, so I take out my head unit and run another set of RCA's straight to the amp, same thing except now the speakers will not play period, as soon as I turn the headunit on it just makes those loud clicking and popping noises constant which is very erratic and difficult to listen to.

At this point I completely remove the crossover and wire the mid straight into the amp. The constant clicking and popping noises are gone, but it still makes the clicking and popping noises whenever I change the volume, EQ, HPF or turn it off and such.

The next step I take is taking my mp3 player and plugging in a mini stereo jack to RCA splitter and use that as the music source instead of the HU. I can only adjust the volume so far but it seems like all the clicking and noise that shouldn't be there is gone. I tried plugging in the mp3 player with the crossover connected and unconnected and it seemed to have fixed it either way.

I guess the only thing left that can be wrong is the head unit (which is a Pioneer Premier 750) has gone bad. The thing that doesn't make sense about this is, the subwoofer RCA output still works perfectly fine and has had absolutely no noise throughout my problem.

I apologize for the lengthy post, but I really am stumped. I've gone by a local audio shop and the guy there was just as stumped as I was. I hadn't changed any wiring or anything prior to installing this and have never had any problems such as this. Please, help me :confused:
 

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There are afew things I would check...

How are your interconnects run? Are they run anywhere near the power cables? You want them a good distance apart from each other.

Also, check your grounds...

You are on the right track with your troubleshooting...

When you used your mp3 player instead of your head unit, you changed two variables...one, you have a different source(instead of the hu with all the cables going to it), and second, you are using other rca's.
Try plugging you mp3 player into the existing rca's. That way you can narrow it down further.
If it goes away, then its not your cables...now you can focus on your HU. Not so much as the outputs, but possible how the HU is wired up...

I hope this helped...good luck....
 

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sounds like an nightmere amb,just some obvious things you can try,select another grounding piont other than factory harness ,make shure all rca,s are pushed in tight,improve grnd. from chass. to batt, and sounds like your gains are a bit? too high -background hiss at low vol.- or hook it up 4 ch stereo and see how it sounds!!! if its easy for you to do improve-larger ga. wire from your alternator pwr. wire to your batt,wont help with your noise problems but will allow a little more current with under hood temps.
 

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Discussion Starter #4
I dunno why it would be the ground for the H/U, because nothing has changed as far as the headunit is concerned. As far as wiring, I've already upgraded by doing the "big 3" with 1/0 wire. My gains are all the way down too. I'm gonna try using the RCAs i have run tomorrow with my mp3 player. I'm beginning to worry that it's my H/U that's messed up.
 

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I had the same problem before. If you have an equalizer, the equalizer could have something wrong with it. I would look into that area because I had similar problems when using Audiobahns AEX 30band eq. If you don't fix it, things will blow!
 

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Is a speaker wire grounded or pinched somewere? Some of the noises you hear may be HF oscillation and could possibly be damaging. Amps that do not use "ground" for the negative and float the outputs will work and not blow smoke if one terminal is grounded but they sure do get pissed!

Chad
 

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Discussion Starter #7
The only equalizer I have is the on in the HU. I don't think the speaker wire is the problem because it plays fine when I hook up my mp3 player to it. I'm starting to wonder if the RCA channel has gone bad. Is that a possibility?
 

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Yes it is possible...anything is possible. Do you have access to the back of the head unit? If so, does wiggling the rca jack make the noise happen or make it worse?

If you wanted to spend the money, you can make a butt-set similar(a very dumbed down version the phone guys use). All you need a is an old analog phone handset, two leads from radioshack and some solder. Just open up the handset and gut it except for the speaker, solder one lead to the + and one to the -. Then put the headset back together and whoala!!! a pretty decent low level audio tester.

Then just connect the + lead to the tip of the amp side of the rca and the - lead to the outer ring of the rca. You should be able to get a decent signal there. If there is noise (popping) then get a different cable(the one you were using for your mp3 player and do the same test. If there is still noise, the try to connect to the output of your HUs rcs outs. Its not as easy to do because they are female and not male, but it can be done if you have the right kind of leads. I used the lead that are used for a multi-meter because of the little probes on the end. if the noise is still there, then its prob. your HU.

Also after reading your post again, you said the sub rca outs do not have this same issue...if you have 3 sets of rca outs, does the outs for the rear have the same issue? if it doesn't, and you are not using them, is there anything stopping you from using the rear outs instead of the front?

good luck...

also remember to turn the volume down all the way and then ramp it up to a decent level so you don't blast your ears.
 

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hey amb.looked at some info on another board,the person had a pioneer 9600mp,after all the niose problems,the tecs had him get a piece of short wire and tuoch the grnd. shield portion of one of the rca,s the other end touch the chassis if the nioses are diminished ther is a internal hu grnd. problem creating a grnd loop-sent in for repair, or you can grnd the hu case to your cars chass,and see how it goes.
 

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dodgerblue said:
you can grnd the hu case to your cars chass,and see how it goes.

I dont know if that would solve your problem but if possible I like to ground the HU... does wonders for rejecting noise from entering your rcas or internal amp. but who uses an internal amp :eek: say it aint so! :D
 

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Discussion Starter #11 (Edited)
Thanks for all the input guys. Today I did a bit more troubleshooting. I used the same RCA's that go through my H/U with my mp3 player and it played fine. The next thing I did was plugged the RCAs into the rear output. Had some interesting results. Engine noise returned in both speakers, but the popping was limited to only one of the speakers. The popping isn't constant anymore but it does still occur any time I change any HPF, EQ, or turning the volume from 0 to 1 or 1 to 0. It also seems to occur whenever I turn the music up pretty loud but not to the point where it would obviously be stressing the speaker's power handeling. Does all this mean the H/U is just completely screwed up? Or should I try using a different ground maybe?
 

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If the RCA's were good with your mp3 player, it is the HU or at least one of the connections or op-amps in the HU.
 

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Check your speakers... make sure they aren't grounded anywhere to the door/metal.
 

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Discussion Starter #15
It's kinda hard to take the speakers out now because they're screwed in and sealed with the clay. Although, If it plays fine through my head unit, wouldn't it eliminate my speakers as being the problem?
 

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andrewbr500 said:
It's kinda hard to take the speakers out now because they're screwed in and sealed with the clay. Although, If it plays fine through my head unit, wouldn't it eliminate my speakers as being the problem?
Your mp3 player isn't grounded to the car though.

Have you tried moving your headunit ground?
 

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Discussion Starter #18
Well, I plugged in my friends 6500 pioneer into my system and all noise is gone so I'm assuming the RCAs have some sort of ground loop problem. I guess I'm in the market for a new head unit. I was looking at some of the eclipse 8V head units, maybe those won't break on me :(
 

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Discussion Starter #19
Well everyone, after a bunch of forum browsing and troubleshooting, I have fixed the problem. What I did was took some speaker wire and wrapped it around the outer metal part of the each RCA cable and grounded it to the same ground as my headunit. All noise is gone and the G18s sound amazing :eek: All static is gone but I do suspect they are slapping against the doorpanel a little bit but that's ok, for now. Now that I have fixed the problem, I was just wondering how did this happen? What did I do that caused it to have this problem?
 
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