Weird humming prob
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=43126
Printed Date: May 31, 2024 at 10:51 PM
Topic: Weird humming prob
Posted By: ashcan
Subject: Weird humming prob
Date Posted: November 16, 2004 at 2:38 PM
Okay I have a single 12" Memphis Studio sub and a Depth charge 200w amp....Sometimes when I get in my car and start it up I get this weird humming sound...Kinda sounds like a grinding humm.....I have umplugged the RCAs from the amp and it still happens so its somewhere on the amp side...Is there any thing I can check or do to resolve this problem.... The problem has just recently started....I guess about a month ago...before that it was fine....No humm... Help Please...
Replies:
Posted By: Ravendarat
Date Posted: November 16, 2004 at 2:50 PM
possibly a poor ground, is it rpm related, could also be a problem with the driver but I doubt it
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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer
Posted By: maaudio1
Date Posted: November 17, 2004 at 11:02 AM
^That would be my first guess. Ground problem. Recheck or even relocate you ground on the amp and see if that helps.
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2004 Mazda 3s Hatchback
2- MTX 4500 8" subs powered by MTX 251D
Posted By: ashcan
Date Posted: November 18, 2004 at 7:07 PM
OK....I moved my ground to the Seatbelt bolt that goes into the frame.... I took a dremel grinder and took it down to bare metal.....So its grounded good now.... I still have the same weird humm....It does it for a while then it will stop....Its not RPM related you can rev the motor and no change in tone or frequency of the hum.....I am starting to wonder if my amp is going bad and this is the first sign..... It still plays fine and sounds good but when you turn it down you can hear it... Any more suggestions....
Posted By: uthinkuknoaudio
Date Posted: November 18, 2004 at 7:15 PM
what guage of ground wire are you using? It could be too small, or another problem could be that you have bad RCA's.
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"I don't play games. I play Nakamichi and that for real yo" - Probably some japanese kid said this in the early 80's trying to sell stereo out of his trunk lol.
Posted By: ashcan
Date Posted: November 18, 2004 at 7:21 PM
Its a 200 watt amp so I used 8Ga pow and ground.... Its not in the RCAs....I have unplugged the RCAs from the amp and you still have the sound.... Could the remote wire cause A noise....I am running a factory headunit so I used the ACC pow Wire from behind the radio to turn on the amp.... Any other ideas???
Posted By: archemedes
Date Posted: November 18, 2004 at 7:25 PM
pull the amp and bench test it, could be internal to the amp, and you could change all the wiring and still not find the problem
Posted By: uthinkuknoaudio
Date Posted: November 18, 2004 at 7:26 PM
"Ditto archemedes" - Get it bench tested, i really don't think your remote line could make a difference on it. Your ground seems fine for a 200 W amp ... interesting...
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"I don't play games. I play Nakamichi and that for real yo" - Probably some japanese kid said this in the early 80's trying to sell stereo out of his trunk lol.
Posted By: xTimx
Date Posted: November 18, 2004 at 7:27 PM
does it do it when the car is shut off as well? try that, and if it still does it then :P sorry i have never heard anything like that. you may want to check your ground (again) to see if your connections are corroded. (even on the amp). make sure you dremel the actual bolt too. make SURE you have a good connection.
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xTimx
Posted By: maaudio1
Date Posted: November 18, 2004 at 8:13 PM
Starting to sound like an internal problem on the amp. If you know somebody that might let you borrow an amp for 5-10 minutes. Hook it up and see if it goes away.
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2004 Mazda 3s Hatchback
2- MTX 4500 8" subs powered by MTX 251D
Posted By: uthinkuknoaudio
Date Posted: November 18, 2004 at 8:18 PM
That is a good idea, but pray its not your ground ... I would hate to lend my buddy an amp for 5 minutes and have it blow up lol.
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"I don't play games. I play Nakamichi and that for real yo" - Probably some japanese kid said this in the early 80's trying to sell stereo out of his trunk lol.
Posted By: Steven Kephart
Date Posted: November 18, 2004 at 11:46 PM
Hehe, I know exactly what it is. Your clue that you are using your factory head unit is what gives it away. You are using high level inputs on the amp, that are hooked up to the rear speakers, right? Well when you shut your door, the difference of air pressure moves the cones of the speakers, thereby creating a signal that your amplifier amplifies to the subwoofers which move and in turn vibrate the rear speakers even more. You get a wierd low frequency feedback going on. How do you have your remote turn on hooked up? If you can hook it up to the ignition of your vehicle, then the amplifier won't turn on until you put the key in the car. This should take care of your problem unless you close your door with the vehicle turned on. The other thing you can do is get the signal from the front speakers instead. You may still get a noise from the subs when you close the doors, but it won't feed back on itself as the subs shouldn't move the front speakers like the rear speakers. Good luck! Steven Kephart Adire Audio -------------
Posted By: xtremsounds
Date Posted: November 20, 2004 at 12:35 AM
when you installed your system did you run the power wires and the rca's next to eachother ? Sometimes if you buy cheaper powerwire the wire is'nt sheilded enough . which means your rca's are recieving a volt signal from the power wire causeing interference if it only does it when the car is on and it doesnt raise up and down when you rev your engine it means from 12 volts the power isnt strong enough to bleed through power wire , but when it reaches 14 volts then the shield fails try moving your rcas away from the power wire and see if it stops if that doesnt help get a ground loop isolator should be around 15.00 for a good one i sell a tsunami piece that is the best on the market if your interested i could send you one PAC makes a good one too Good Luck oh by the way the 200 wattt amp should only need 10 guage to 8 guage
Posted By: xtremsounds
Date Posted: November 20, 2004 at 12:43 AM
oops i missed one of your replys if its not your rca's. steven is right , best thing in this case i would do is get speaker baffles so the pressure doesnt change , and also defiantly change your remote wire to ignition if its not already on there
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