Hisssssss

[matt_bennett05 10+ year member]

What tips/tricks do you guys use to find the slight hiss that is made from your headunits? I've got a CDA-117 that has always seemed to have it (going from a DEH-9800BT which also had it). It doesn't drive me nuts but what are some tricks/tips I could try to eliminate it? Not using the headunit amp. Knu Karma cables ran separately on 02 GMC Yukon passenger side (power on driver side). Kicker ZR600 on front doors and ZR240 on rear fill; both gained appropriately though less than they could be safely. Sub amp and door amps share same remote.

Tried using RCA output from ZR600 to ZR240 but that seemed to make it more apparent. All contacts on modules are clean and crisp.

Also, each amp I've used on doors which include Aura RPM2300, ZR's, MB Q RAA2400, and others have had similar hiss so I can't think it would be the amps.

@ Keep_Hope_Alive !!!

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[matt_bennett05 10+ year member]

Someone help me w/ that mention tag please~

 

[butterMilk 10+ year member]

@keep_hope_alive ;

 

[keep_hope_alive Premium Member]

"hiss" or noise is inherent in the equipment and the audio recording itself.

each stage of gain worsens the hiss.

my older alpine all had hiss after vol 24.

my 9887 has inaudible hiss, even at full volume.

my xtant amps have inaudible hiss.

the test for hiss is a 0-bit track (like found on IASCA test CD's and Autosound 2000 Disc 102).

 

[matt_bennett05 10+ year member]

"hiss" or noise is inherent in the equipment and the audio recording itself.
each stage of gain worsens the hiss.

my older alpine all had hiss after vol 24.

my 9887 has inaudible hiss, even at full volume.

my xtant amps have inaudible hiss.

the test for hiss is a 0-bit track (like found on IASCA test CD's and Autosound 2000 Disc 102).

Ok I can tell that different tracks have different levels.

And by inaudible hiss you don't hear it? (Inaudible means unable to hear just making sure my definition matches yours).

How can something exist that isn't audible (know our ears can't hear everything but I guess I'm confused by your meaning unless you were scoping).

Is there an A/B (500+ rms 2/4 channel) that could help eliminate some of this in my casse you have knowledge on? And also, is there a spec I'm missing or should pay better attention to on amplifier spec sheets?

 

[TDot 10+ year member]

I've used stuff in recording studios that take away and mask hiss that I wonder if there is something on the car audio side that is similar, or has been transplanted to.

1/ a noise gate: basically a threshold is set and if the audio drops below that threshold the gate would activate and basically close off the audio. This would have to be put after the amp and before the speakers. It is almost bewildering to me that something like that isn't built into the output of amps. This doesn't eliminate hiss in your track, but eliminates hiss "in your speaker". So you'll hear hiss in your music, but when the music is gone the hiss will be gone.

2/ noise imprint: basically this looks at your pure noise floor and adjusts eq curves and noise thresholds to remove that noise. This is far more complicated and more expensive tHan gates, and cheaper algorithms adds in a little bit of audio artifacts, but the good ones sound pristine and pure as long as you are not trying to totally eliminate all of the "air".

I wish these things were available.

If I wanted to take up some more room in my trunk I would grab some gates and hook them up. If you're not concerned about trunk space that is the best way to go. For four channels the space taken up would be a minimum of 19"x4" and then convert dc to ac 120v.

 

[matt_bennett05 10+ year member]

I've used stuff in recording studios that take away and mask hiss that I wonder if there is something on the car audio side that is similar, or has been transplanted to.
1/ a noise gate: basically a threshold is set and if the audio drops below that threshold the gate would activate and basically close off the audio. This would have to be put after the amp and before the speakers. It is almost bewildering to me that something like that isn't built into the output of amps. This doesn't eliminate hiss in your track, but eliminates hiss "in your speaker". So you'll hear hiss in your music, but when the music is gone the hiss will be gone.

2/ noise imprint: basically this looks at your pure noise floor and adjusts eq curves and noise thresholds to remove that noise. This is far more complicated and more expensive tHan gates, and cheaper algorithms adds in a little bit of audio artifacts, but the good ones sound pristine and pure as long as you are not trying to totally eliminate all of the "air".

I wish these things were available.

If I wanted to take up some more room in my trunk I would grab some gates and hook them up. If you're not concerned about trunk space that is the best way to go. For four channels the space taken up would be a minimum of 19"x4" and then convert dc to ac 120v.

Wooooh, that's a WHOLE LOT DEEPER that I'd be willing to go to eliminate it.

I also got to thinking... could me installing the BT adaptor in the dash (up front tucked under top of the dash) be causing any of this? Could relocating it help?

 

[keep_hope_alive Premium Member]

my xtant amps have a noise gate. but that's only for when the music is paused.

inaudible means we cannot discern it from the noise floor (general background noise floor in a car that off, in a garage, windows up, is 20dBA - 30dBA) while driving the noise floor is commonly 50dBA - 60dBA.

everything makes noise. whether or not you can hear it is dependent on other factors.

older amps have more background hiss than newer amps.

you could snag up a Boston Acoustics GT-2300 for $300 right now. it should be quiet. it's not as good as the previous GT-28. you really want the versions made in Italy.

 

---------- Post added at 11:40 AM ---------- Previous post was at 11:39 AM ----------

 

certainly, there is noise in a BT system. you need to evaluate noise with a 0-bit track from a test CD.

 

[rugdnit 10+ year member]

you could snag up a Boston Acoustics GT-2300 for $300 right now. it should be quiet. it's not as good as the previous GT-28. you really want the versions made in Italy.

 

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I would talk to RexRoad over at DIYMA about those GT's. I believe he has run at least the first two gens. No difference. In fact not all of the original GT's ( all silver sink ) were made in Italy. I wouldn't sweat where it's made so much as the design-- which is pretty solid. I have even heard more than a few guys say that the Made In Italy tag is a bit of a hoodwink.

 

[keep_hope_alive Premium Member]

I would talk to RexRoad over at DIYMA about those GT's. I believe he has run at least the first two gens. No difference. In fact not all of the original GT's ( all silver sink ) were made in Italy. I wouldn't sweat where it's made so much as the design-- which is pretty solid. I have even heard more than a few guys say that the Made In Italy tag is a bit of a hoodwink.

yep, i saw those threads on DIYMA. i agree that the design is more important, but the biggest thing about where it's made is consistency and component quality. i have no issue with a good design being made in asia where they just churn out PCB's like no one else.

I was sad to see BA leave the car audio scene, i've always liked their amps and speakers. Those GT amps are the best amplifier value on the market today, IMO. we are all silly for not picking up a few.

 

[rugdnit 10+ year member]

Yeah... Wasn't trying to be argumentative at all. I will add that there is a famous joke about " made in Italy " something along the lines of if was manufactured on a Monday or Friday it's probably going to have some issues.... //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif