I have had this happening before with my two old 10" subs before they died so I hope I didn't blow it or something? I just have 1 15" sub connected to 850watt amp thats been in my car approx. year and a half.
I noticed lately now and then a thumping sound would come out and that my front left speaker was cutting out badly. Today I decided to mess with it and I fixed the speaker up front (I thought wire crossing was causing sub distortion). I also redid the amp wires making sure they were all in nice and tight.
Now I turn the car on and almost constantly it makes a radio static noise (the kind when you listen to a high school football game on the radio) and the thump noise. I'm not sure whats wrong unless its the speaker wire inside the sub is coming lose?
With my old 10" subs I got real rough and blew 1 of them. Then I had a 12" and blew that as well. So I have been pretty kind to this 15" I don't think I abused it, but I have been playing some sick beats lately.
Any insight as to what I should do would be appreciated. I know its not something to put off so I have turned off my entire sound system until I resolve this...
Replies (5)
swez on 01/24/2006 17:05:05
Wise move... shut er down until you find the root cause.
1. Look at all your grounding points first. That's HU and amp grounds and solid RCA lines as well. The HU and any/all amps, need bare metal grounds to floor pan.
2. Check your work again, (at low volume) after the grounds are right and tight. Things back to normal?
3. If not, remove the input RCA's from the amp and determine if the issues are there or gone now. Try gently wiggling the RCA inputs to your amp and see if you get the noise back, w/o jacks plugged in.
If these steps do not cure the problem, we have to look deeper.
What make and model HU and amp(s) do you have now?
Swez
lakecityransom on 01/24/2006 17:24:49
Okay thanks heres my equipment: JVC KD-LH810 mp3 player, 850watt farenheight amp, mtx 15" sub)
I turned it on again about 45 mins later and it was fine, tried going full power for a sec then down and then tested a few more times at longer intervals it worked completely fine... so I kept it on then listened one last time before I turned the car off, no problems. Kinda strange. Gonna keep an ear on it though :P, thanks.
swez on 01/24/2006 18:11:37
Intermittent issues are the hardest to track down. If you have a DC Voltmeter, it would be good to connect it to the amp power suppy leads and watch the voltage. If you see a large dip in power on the meter and the amp goes into "flaky" mode, it's a sign of possible internal problems with the amp or it is not getting enough power from the ALT/BAT.
I would anticipate a nominal voltage at the amp terminals to be in a range between 14.0 volts at startup of the vehicle and it will gradually drop to a steady state of ~13.5 volts. If you see a major drop to under 12.0 volts at any time, this may be a big part of the problem. (low voltage)
I would expect that to happen only when running the system with the BAT and engine is off.
What is the model number of your amp and sub?
Swez
jazzbass on 01/24/2006 22:50:41
My $0.02 worth, I agree with Swez regarding the grounding issues. I was convinced that my Main Amp, a US Acoustics 4065 was gone because I started getting a thump, then the amp started immediately going into a protection mode and shutting down as soon as power was applied. I checked all of my connections for continuity and shorts and all were good. I was getting ready to remove the amp. Last check, I pulled up the carpet and nudged the ground connection... music came from all around!
In summary, I went through all of my grounds and made sure I had good clean bare metal contact. Life is good once again! It is surprising how important that negative ground connection is. Everyone thinks of big gauge power cables and capacitors on their inrunning lines, but the ground is every bit as important.
MrBrownstone on 01/25/2006 23:46:46
the static noise sounds quite familiar...did you monkey with the gain controls on the amplifier? usually, turning the gain down (or way up) will either remove or induce issues with the whining....
The thumps, that could be amp turn-on noise, grounding from the headunit or any other equipment along the way.
I noticed lately now and then a thumping sound would come out and that my front left speaker was cutting out badly. Today I decided to mess with it and I fixed the speaker up front (I thought wire crossing was causing sub distortion). I also redid the amp wires making sure they were all in nice and tight.
Now I turn the car on and almost constantly it makes a radio static noise (the kind when you listen to a high school football game on the radio) and the thump noise. I'm not sure whats wrong unless its the speaker wire inside the sub is coming lose?
With my old 10" subs I got real rough and blew 1 of them. Then I had a 12" and blew that as well. So I have been pretty kind to this 15" I don't think I abused it, but I have been playing some sick beats lately.
Any insight as to what I should do would be appreciated. I know its not something to put off so I have turned off my entire sound system until I resolve this...
Replies (5)
swez on 01/24/2006 17:05:05
Wise move... shut er down until you find the root cause.
1. Look at all your grounding points first. That's HU and amp grounds and solid RCA lines as well. The HU and any/all amps, need bare metal grounds to floor pan.
2. Check your work again, (at low volume) after the grounds are right and tight. Things back to normal?
3. If not, remove the input RCA's from the amp and determine if the issues are there or gone now. Try gently wiggling the RCA inputs to your amp and see if you get the noise back, w/o jacks plugged in.
If these steps do not cure the problem, we have to look deeper.
What make and model HU and amp(s) do you have now?
Swez
lakecityransom on 01/24/2006 17:24:49
Okay thanks heres my equipment: JVC KD-LH810 mp3 player, 850watt farenheight amp, mtx 15" sub)
I turned it on again about 45 mins later and it was fine, tried going full power for a sec then down and then tested a few more times at longer intervals it worked completely fine... so I kept it on then listened one last time before I turned the car off, no problems. Kinda strange. Gonna keep an ear on it though :P, thanks.
swez on 01/24/2006 18:11:37
Intermittent issues are the hardest to track down. If you have a DC Voltmeter, it would be good to connect it to the amp power suppy leads and watch the voltage. If you see a large dip in power on the meter and the amp goes into "flaky" mode, it's a sign of possible internal problems with the amp or it is not getting enough power from the ALT/BAT.
I would anticipate a nominal voltage at the amp terminals to be in a range between 14.0 volts at startup of the vehicle and it will gradually drop to a steady state of ~13.5 volts. If you see a major drop to under 12.0 volts at any time, this may be a big part of the problem. (low voltage)
I would expect that to happen only when running the system with the BAT and engine is off.
What is the model number of your amp and sub?
Swez
jazzbass on 01/24/2006 22:50:41
My $0.02 worth, I agree with Swez regarding the grounding issues. I was convinced that my Main Amp, a US Acoustics 4065 was gone because I started getting a thump, then the amp started immediately going into a protection mode and shutting down as soon as power was applied. I checked all of my connections for continuity and shorts and all were good. I was getting ready to remove the amp. Last check, I pulled up the carpet and nudged the ground connection... music came from all around!
In summary, I went through all of my grounds and made sure I had good clean bare metal contact. Life is good once again! It is surprising how important that negative ground connection is. Everyone thinks of big gauge power cables and capacitors on their inrunning lines, but the ground is every bit as important.
MrBrownstone on 01/25/2006 23:46:46
the static noise sounds quite familiar...did you monkey with the gain controls on the amplifier? usually, turning the gain down (or way up) will either remove or induce issues with the whining....
The thumps, that could be amp turn-on noise, grounding from the headunit or any other equipment along the way.
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