# Speaker Hiss with volume at 0 after amp install



## digitaldav (Dec 8, 2010)

I just got done installing JL Audio XD600/6 . Also adjusted input sensitivity as per manual. System sounds great but when turned all the way down I hear a slight hissing sound from speakers.
Any thoughts?


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

typical noise floor... amps aren't silent... 

could be too high of gain.. 

try a zero bit track and see what that does... or a mute plug...


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## digitaldav (Dec 8, 2010)

Even with the gain turned to 0 I still here noise. Could the rca input cables cause this?


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## mcm308 (Nov 24, 2010)

Aaron'z 2.5RS/WRX said:


> typical noise floor... amps aren't silent...



This... 

some amps are louder then others


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## digitaldav (Dec 8, 2010)

mcm308 said:


> This...
> 
> some amps are louder then others


So there is nothing I can do to remove the hiss?


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## symphonix (Jun 2, 2011)

Would this be a case of alternator whine?


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## digitaldav (Dec 8, 2010)

symphonix said:


> Would this be a case of alternator whine?


No unfortunately the hiss is there without the car running.


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## b&camp (Jan 27, 2011)

Assuming the HU has a zero-bit mute circuit, turning it down all the way and the hiss still being there tells me that it is simply the amp's noise floor. Like Aaron said, muting plugs in the input of the amp will let you know for sure. Solution: Don't listen to music with the volume at 0.


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## digitaldav (Dec 8, 2010)

b&camp said:


> Assuming the HU has a zero-bit mute circuit, turning it down all the way and the hiss still being there tells me that it is simply the amp's noise floor. Like Aaron said, muting plugs in the input of the amp will let you know for sure. Solution: Don't listen to music with the volume at 0.



Mute plugs< I will give this a try!
Thanks


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## digitaldav (Dec 8, 2010)

OK I did the rca shorted plugs and the noise is gone!
So that tells me twisted signal wires from head unit are picking up noise or more likely the headunit sucks..

Is there anything else that can be done besides replacing headunit?


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## InCarAudioVideo (Dec 4, 2010)

I wonder if you could install an eq between the hu and amp and cut off the noise?

on a stage mixer there's a low hz cut to remove floor noise, so the same concept can be applied, but its a trial & error to pick the hz to cut... and it might not work


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## digitaldav (Dec 8, 2010)

InCarAudioVideo said:


> I wonder if you could install an eq between the hu and amp and cut off the noise?
> 
> on a stage mixer there's a low hz cut to remove floor noise, so the same concept can be applied, but its a trial & error to pick the hz to cut... and it might not work


Thanks for the idea, but I dont know if I want to add more components like an eq. So if there is nothing else that can be done to the existing system I guess I will have to live with the noise or keep the volume up!


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## Brian_smith06 (Jan 31, 2008)

What kind of deck do you have?


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## ryan s (Dec 19, 2006)

I've had quite a few amps in my car (same everything else, just swapping amps) and I know my hiss is the headunit. With "6.5v" preouts, I've had amps that can be turned down to accept 8v inputs and the hiss was still there.

If your headunit (or anyone else's for that matter) is like mine, there's 2 things I notice. One is that if the white screen comes on, the noise changes pitch. The 860 has an OEL display or something like that, which some say contributes to noise. Second, if I switch sources...especially to CD...the hiss changes and I can hear the CD mechanism working through the speakers.

And one more thing...I have the tweeters attenuated through the headunit since the amp's gains are otherwise all the way down. Most of the hiss is through the tweeters so I wonder if that plays a part. Haven't played with that setting to test it, yet.

So while the amp may be noisy, in my experience, the chance of a noisy headunit is just as good...


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## digitaldav (Dec 8, 2010)

Yes its definitely not in the amp, I proved that using the shorted rca's. 
To Brian's question, what deck am I using. It's the stock E90 BMW head unit with Hi Fi.


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## envisionelec (Dec 14, 2005)

digitaldav said:


> Yes its definitely not in the amp, I proved that using the shorted rca's.
> To Brian's question, what deck am I using. It's the stock E90 BMW head unit with Hi Fi.


Are noise gates still available on the car audio market? This would fix your hiss between tracks. I hate hiss - and would do this in a nanosecond.


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## digitaldav (Dec 8, 2010)

envisionelec said:


> Are noise gates still available on the car audio market? This would fix your hiss between tracks. I hate hiss - and would do this in a nanosecond.


I'm not familiar with noise gates. Maybey others may chime in...


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