White Noise? No 100% Mute
Thread Starter
Racer
Joined: Feb 2010
Posts: 416
Likes: 43
White Noise? No 100% Mute
2006 C6 - OnStar Equipped
Aftermarket Alpine InDash / Aftermarket SoundStream Speakers
As soon as the car is powered on you can hear the radio come on and the white noise come through the speakers. If you turn up the volume the white noise goes up with it. If you mute the system, it doesn't mute 100%, you can still hear the radio faintly in the background.
I did not do the install myself so I'm not sure where to start..
Any ideas ? ? ?
Aftermarket Alpine InDash / Aftermarket SoundStream Speakers
As soon as the car is powered on you can hear the radio come on and the white noise come through the speakers. If you turn up the volume the white noise goes up with it. If you mute the system, it doesn't mute 100%, you can still hear the radio faintly in the background.
I did not do the install myself so I'm not sure where to start..
Any ideas ? ? ?
Advanced
Joined: Dec 2015
Posts: 97
Likes: 7
From: Charleston South Carolina
2006 C6 - OnStar Equipped
Aftermarket Alpine InDash / Aftermarket SoundStream Speakers
As soon as the car is powered on you can hear the radio come on and the white noise come through the speakers. If you turn up the volume the white noise goes up with it. If you mute the system, it doesn't mute 100%, you can still hear the radio faintly in the background.
I did not do the install myself so I'm not sure where to start..
Any ideas ? ? ?
Aftermarket Alpine InDash / Aftermarket SoundStream Speakers
As soon as the car is powered on you can hear the radio come on and the white noise come through the speakers. If you turn up the volume the white noise goes up with it. If you mute the system, it doesn't mute 100%, you can still hear the radio faintly in the background.
I did not do the install myself so I'm not sure where to start..
Any ideas ? ? ?
Steve
Thread Starter
Racer
Joined: Feb 2010
Posts: 416
Likes: 43
This sounds like the same issue I have after installing new everything except the headunit. It's also consistent with many people in the past after doing upgrades. More than likely you've got a ground loop issue, there are a number of posts on here discussing and steps to try to eliminate it. Do you have an external amplifier?
Steve
Steve
Advanced
Joined: Dec 2015
Posts: 97
Likes: 7
From: Charleston South Carolina
I'd certainly say before doing all that I'd try some diagnostic work first. This site had a decent walkthru on how to check where the noise is coming from about 1/4 the way down under alternator whine. It walks step by step into how to eliminate equipment as the culprit. http://www.termpro.com/asp/pubs.asp?ID=121
I know in the other thread you said not to say it's your ground but odds are the ground or the wiring is your problem. If you replaced the stock head unit with an aftermarket one why retain the stock amp? Easiest thing to me would be to run new speaker wires from the head unit to the speakers and bypass the amp. The other thing you could try is 2 fold. First pull the radio out and disconnect the feeds to the amp to see if the noise goes away. Next connecting a single speaker to the radio bypassing the amp and see if it has noise. If it does then the noise is coming from the radio and you need to address the radio or radio wiring. If the sound is clear then you at least know the radio is good and the wiring to the amp or there could be a ground issue between the radio and amp.
Steve
Le Mans Master
Joined: Nov 2003
Posts: 5,401
Likes: 52
From: Norman OK
As I said in the General forum, when I had this problem it was a bad adapter. I used a OS adapter from Dennis, he sent me a replacement and that solved the problem. Only difference than OP is I replaced speakers and Amp at the same time.
Racer
Joined: May 2016
Posts: 294
Likes: 192
From: TN
I have eliminated the head unit and the adapter both. Have tried two different new in box headhunts, my Kenwood and a Pioneer. Have also tried two different brand new in box adapters from different manufacturers. Have also grounded the head unit directly to the frame rail, seat mount and factory grounding point per the GM manual. With 8 gauge wire.
None of the above changed the symptom even one bit.
None of the above changed the symptom even one bit.
Thread Starter
Racer
Joined: Feb 2010
Posts: 416
Likes: 43
I'll dig into it tomorrow. On my 07 Z06 I had a similar issue, but got it corrected before I put everything back together. Problem is it was 6 years ago and I don't recall what I did. I knew it had something to do with the wiring harness/rcas
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Thread Starter
Racer
Joined: Feb 2010
Posts: 416
Likes: 43
Racer
Joined: May 2016
Posts: 294
Likes: 192
From: TN
My car is non-Bose, non-Onstar. Hopefully someone can offer up a solution. I agree with the above statement too, it has to be something with the way the factory Delphi amp is processing the signal from the aftermarket HU. That is all that's left...
Pro
Joined: Oct 2014
Posts: 616
Likes: 193
From: Gilbert AZ
The problem you describe is exactly what happens when you drive the input of an amplifier with an already amplified signal. The white noise you hear is simply the noise floor of the radios already amplified output, being amplified again. This is assuming you are supplying the audio signal to the OEM amplifier via the radios speaker wire outputs.
The specification for this is "Signal to Noise". When you connect the audio output of one device into the input of another device, signal to noise ratios become important. An audio engineering rule of thumb is that the device being driven should have at least -10dB lower S/N than its source in the audio path.
The signal to noise of the amplified outputs of a typical aftermarket radio are around -75dB A-weighted. This means the OEM amp would need to have -85dBA S/N for the noise not to become audibly worse. Unfortunately, this is not the case, the OEM amp has roughly the same signal to noise ratio as the Alpine radio, hence the audible increase white noise.
The proper corrective action would be to either drive the speakers directly with the output of the radio and eliminate the OEM amp, or to replace the OEM amplifier with an aftermarket amplifier that uses the RCA (low level) outputs from the Alpine radio.
Either way, you need to get the OEM amp out of the signal path if you want to reduce the noise.
Garry
The specification for this is "Signal to Noise". When you connect the audio output of one device into the input of another device, signal to noise ratios become important. An audio engineering rule of thumb is that the device being driven should have at least -10dB lower S/N than its source in the audio path.
The signal to noise of the amplified outputs of a typical aftermarket radio are around -75dB A-weighted. This means the OEM amp would need to have -85dBA S/N for the noise not to become audibly worse. Unfortunately, this is not the case, the OEM amp has roughly the same signal to noise ratio as the Alpine radio, hence the audible increase white noise.
The proper corrective action would be to either drive the speakers directly with the output of the radio and eliminate the OEM amp, or to replace the OEM amplifier with an aftermarket amplifier that uses the RCA (low level) outputs from the Alpine radio.
Either way, you need to get the OEM amp out of the signal path if you want to reduce the noise.
Garry
Thread Starter
Racer
Joined: Feb 2010
Posts: 416
Likes: 43
Racer
Joined: May 2016
Posts: 294
Likes: 192
From: TN
The problem you describe is exactly what happens when you drive the input of an amplifier with an already amplified signal. The white noise you hear is simply the noise floor of the radios already amplified output, being amplified again. This is assuming you are supplying the audio signal to the OEM amplifier via the radios speaker wire outputs.
The specification for this is "Signal to Noise". When you connect the audio output of one device into the input of another device, signal to noise ratios become important. An audio engineering rule of thumb is that the device being driven should have at least -10dB lower S/N than its source in the audio path.
The signal to noise of the amplified outputs of a typical aftermarket radio are around -75dB A-weighted. This means the OEM amp would need to have -85dBA S/N for the noise not to become audibly worse. Unfortunately, this is not the case, the OEM amp has roughly the same signal to noise ratio as the Alpine radio, hence the audible increase white noise.
The proper corrective action would be to either drive the speakers directly with the output of the radio and eliminate the OEM amp, or to replace the OEM amplifier with an aftermarket amplifier that uses the RCA (low level) outputs from the Alpine radio.
Either way, you need to get the OEM amp out of the signal path if you want to reduce the noise.
Garry
The specification for this is "Signal to Noise". When you connect the audio output of one device into the input of another device, signal to noise ratios become important. An audio engineering rule of thumb is that the device being driven should have at least -10dB lower S/N than its source in the audio path.
The signal to noise of the amplified outputs of a typical aftermarket radio are around -75dB A-weighted. This means the OEM amp would need to have -85dBA S/N for the noise not to become audibly worse. Unfortunately, this is not the case, the OEM amp has roughly the same signal to noise ratio as the Alpine radio, hence the audible increase white noise.
The proper corrective action would be to either drive the speakers directly with the output of the radio and eliminate the OEM amp, or to replace the OEM amplifier with an aftermarket amplifier that uses the RCA (low level) outputs from the Alpine radio.
Either way, you need to get the OEM amp out of the signal path if you want to reduce the noise.
Garry
Racer
Joined: May 2016
Posts: 294
Likes: 192
From: TN
The problem you describe is exactly what happens when you drive the input of an amplifier with an already amplified signal. The white noise you hear is simply the noise floor of the radios already amplified output, being amplified again. This is assuming you are supplying the audio signal to the OEM amplifier via the radios speaker wire outputs.
The specification for this is "Signal to Noise". When you connect the audio output of one device into the input of another device, signal to noise ratios become important. An audio engineering rule of thumb is that the device being driven should have at least -10dB lower S/N than its source in the audio path.
The signal to noise of the amplified outputs of a typical aftermarket radio are around -75dB A-weighted. This means the OEM amp would need to have -85dBA S/N for the noise not to become audibly worse. Unfortunately, this is not the case, the OEM amp has roughly the same signal to noise ratio as the Alpine radio, hence the audible increase white noise.
The proper corrective action would be to either drive the speakers directly with the output of the radio and eliminate the OEM amp, or to replace the OEM amplifier with an aftermarket amplifier that uses the RCA (low level) outputs from the Alpine radio.
Either way, you need to get the OEM amp out of the signal path if you want to reduce the noise.
Garry
The specification for this is "Signal to Noise". When you connect the audio output of one device into the input of another device, signal to noise ratios become important. An audio engineering rule of thumb is that the device being driven should have at least -10dB lower S/N than its source in the audio path.
The signal to noise of the amplified outputs of a typical aftermarket radio are around -75dB A-weighted. This means the OEM amp would need to have -85dBA S/N for the noise not to become audibly worse. Unfortunately, this is not the case, the OEM amp has roughly the same signal to noise ratio as the Alpine radio, hence the audible increase white noise.
The proper corrective action would be to either drive the speakers directly with the output of the radio and eliminate the OEM amp, or to replace the OEM amplifier with an aftermarket amplifier that uses the RCA (low level) outputs from the Alpine radio.
Either way, you need to get the OEM amp out of the signal path if you want to reduce the noise.
Garry
Run the stock base Delphi amp off the F&R RCA's from my deck? I could wire in RCAs for the harness then the signal into the Amp wouldn't be amplified, correct?
Pro
Joined: Oct 2014
Posts: 616
Likes: 193
From: Gilbert AZ
Manners,
If you can determine how to do that, yes it might work. Here are the details that you'd have to learn:
1. Will the Delphi amp accept unbalanced, common ground inputs like the RCA's from your Alpine? I have not tested a Delphi amp so I have no idea, but I'd be pretty suspect that it might not. If it won't, your plan won't work.
2. What is the acceptable input level for the Delphi amplifier? If it will work with 2 volts, the Alpine's RCA's will be okay. If it needs more than that, you're S.O.L.
3. What is the input impedance of the Delphi amp? The Alpine radio is compatible with input impedances of 1000 ohms and up. Below 1000 ohms and it will cause problems.
To be honest, I have no idea how you can find this stuff out, unless you can get your hands on an amp schematic or something. I have never seen published specs for the Delphi amplifier. Perhaps someone has attempted this in the past and can offer some advice. Best of luck to you.
Garry
If you can determine how to do that, yes it might work. Here are the details that you'd have to learn:
1. Will the Delphi amp accept unbalanced, common ground inputs like the RCA's from your Alpine? I have not tested a Delphi amp so I have no idea, but I'd be pretty suspect that it might not. If it won't, your plan won't work.
2. What is the acceptable input level for the Delphi amplifier? If it will work with 2 volts, the Alpine's RCA's will be okay. If it needs more than that, you're S.O.L.
3. What is the input impedance of the Delphi amp? The Alpine radio is compatible with input impedances of 1000 ohms and up. Below 1000 ohms and it will cause problems.
To be honest, I have no idea how you can find this stuff out, unless you can get your hands on an amp schematic or something. I have never seen published specs for the Delphi amplifier. Perhaps someone has attempted this in the past and can offer some advice. Best of luck to you.
Garry
Last edited by Garry in AZ; May 13, 2016 at 03:25 PM.
Tech Contributor
Joined: May 2003
Posts: 7,035
Likes: 134
From: North Augusta, SC
Many of the adapter instructions incorrectly instruct non-bose owners to snip off the RCA plugs and use the speaker level HU outputs. In C6, ALL cars should be treated as if they are bose for the installation instructions.