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kingsxman
01-30-2006, 10:06 AM
I run NO deck power and I have a Pioneer DEH7400MP as my HU. I believe the volume goes to a level of about "65". I Lets say that I've set my gains with my HU volume at 45 (about 3/4 of full). I understand that the reason to set volume at 3/4 is because most decks will start to put out distortion at 75% total volume.

My question is...I have a few cd's that are recorded pretty low. Normally I'm running my volume for most cd's around 38-46. My AC/DC Back in Black for example (factory cd) is normally run with HU volume on about 51 to 53. Theoretically....shouldnt I be getting distortion at that point from HU? I dont hear it howerver....

I guess my question is...how do you know if distortion is coming from amp or Head Unit?

JimJ
01-30-2006, 10:15 AM
Some head units are more suseptible to clip than others...Eclipse decks are known for having non-clipping preouts even at full tilt boogie.

Running your head unit past the maximum point you used to set your gains is a recipe for clipping your amps if you've set them close to the clipping threshold anyway, however.

kingsxman
01-30-2006, 10:56 AM
Thanks. The thing is though...if its clipping I should hear it. If I set the gains via the gain tutorial....I'm guessing that there is a bit of "play" in there. Its hard sometimes to tell where the distortion is coming from. If your listening to distored guitars....is there clipping or is that just part of the music?

adam71
01-30-2006, 12:54 PM
Some head units are more suseptible to clip than others...Eclipse decks are known for having non-clipping preouts even at full tilt boogie.

Running your head unit past the maximum point you used to set your gains is a recipe for clipping your amps if you've set them close to the clipping threshold anyway, however.

But is the headunit putting out the same voltage when the source material is recorded lower?? I'm not calling you out, just curious myself. I mean if you play a track of digital silence and you crank it way up are you pushing your preouts into clipping?? I guess I've always wondered that. Because if you have source mat'l that is recoreded quiet then your amp will have to see more pre out voltage to get to a certain volume level then say with some mat'l that was recoreded at a loud level.

I guess what I'm asking is does low-level recordings put you at a disadvantage preout wise since you would have crank the deck up.??

JimJ
01-30-2006, 12:57 PM
I guess what I'm asking is does low-level recordings put you at a disadvantage preout wise since you would have crank the deck up.??

Pretty sure that it would.

JimJ
01-30-2006, 12:59 PM
Thanks. The thing is though...if its clipping I should hear it. If I set the gains via the gain tutorial....I'm guessing that there is a bit of "play" in there. Its hard sometimes to tell where the distortion is coming from. If your listening to distored guitars....is there clipping or is that just part of the music?

I have a hard time finding system distortion in rock music, mostly because there's a lot of distortion in the source material to begin with :)

I've found orchestra music is very revealing of distortion. If an oboe doesn't sound like an oboe, or a timpani starts sounding like sonic ***, something's up :)

DBfan187
01-30-2006, 01:00 PM
most pioneer HU's I put on the scope clipped @ volume 61 with a 0dB 1kHz tone with everything set flat.

squeak9798
01-30-2006, 01:06 PM
The reason for using 75% as the gain setting volume is two fold;

1) At some point less than full volume, most decks will begin to clip their output

2) As you have found out, some material is recorded at lower levels. Using 75% of volume gives you some "wiggle room" in volume, so for those lower level recordings you can turn the volume up some more for increased volume. If you set your gains with the volume at 100%, this wouldn't be possible.


And not all clipping is audible, as Jim mentioned.

DBfan187
01-30-2006, 01:08 PM
The reason for using 75% as the gain setting volume is two fold;

1) At some point less than full volume, most decks will begin to clip their output

2) As you have found out, some material is recorded at lower levels. Using 75% of volume gives you some "wiggle room" in volume, so for those lower level recordings you can turn the volume up some more for increased volume. If you set your gains with the volume at 100%, this wouldn't be possible.


And not all clipping is audible, as Jim mentioned.x2

gain overlap is a good thing.

adam71
01-30-2006, 01:09 PM
The reason for using 75% as the gain setting volume is two fold;

1) At some point less than full volume, most decks will begin to clip their output

2) As you have found out, some material is recorded at lower levels. Using 75% of volume gives you some "wiggle room" in volume, so for those lower level recordings you can turn the volume up some more for increased volume. If you set your gains with the volume at 100%, this wouldn't be possible.


And not all clipping is audible, as Jim mentioned.

Oh ok, thanks Squeak. That sheds some light on that for me.:)

kingsxman
01-30-2006, 02:00 PM
most pioneer HU's I put on the scope clipped @ volume 61 with a 0dB 1kHz tone with everything set flat.

That is good information to know.

Thanks all.

$$mok3d
01-30-2006, 04:05 PM
So how do you determine what volume level your head unit starts to clip at. I have a jvc kdar5000 and i think it goes up to 55. I have my gains set for 42 and i havent heard any distortion in the music i litsen to. I rember hearing something about using a head phone jack and listening for it to clip. Can someone give me some insight on this?

squeak9798
01-30-2006, 04:22 PM
So how do you determine what volume level your head unit starts to clip at. I have a jvc kdar5000 and i think it goes up to 55. I have my gains set for 42 and i havent heard any distortion in the music i litsen to. I rember hearing something about using a head phone jack and listening for it to clip. Can someone give me some insight on this?

Only absolute way is with an oscilloscope.


The other way would be to pick up a cheap powered speaker at radio shack and listen for when the distortion begins...but that'd be more inaccurate.