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Just a Little Distortin' (max input RMS level?)

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DocG's picture
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I've been auditioning speakers and amps for a while now. One of my fav test tracks is Shelby Lynne's "Just a Little Lovin'". On several occasions, I noticed distortion on the highest dynamic peak of the song (at 3'03" to be exact). I also have this at home (20+-year-old lo-fi combo) and in my car (B&O sound system). Last friday it was really obvious when demoing a Devialet 110 amp, fed by a Burmester transport and playing thru B&W PM1 speakers. As the dealer couldn't find the Burmester's remote (to rewind the song a little, to have another listen), he swapped it for a Cambridge Audio CDP with remote... and the distortion was markedly less, nearly gone Shock . As my test-CD is a CD-R with WAV-rips (using EAC), he tried the CD-layer of the SACD he has of the same album, and the distortion was gone! The dealer blamed the ripped CD, but I thought a bad rip gives drop-outs, not dynamic distortion. puzzled

So my guess is that the amp's maximum input RMS level is too low for the transport, which makes it clip at the highest dynamic peaks. Could that make sense? Anybody any experience with something like that, with this particular song (it's a classic test track) or other dynamic recordings? Could it be another system synergy issue to take into account?

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RE: Just a Little Distortin' (max input RMS level?)

There is clipping on that recording, Shelby did not want it removed she wanted a live type feel or something, so its on the recording, so maybe not the best test track?

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RE: Just a Little Distortin' (max input RMS level?)

BigH wrote:

There is clipping on that recording, Shelby did not want it removing she wanted a live type feel or something, so its on the recording, so maybe not the best test track?

But isn't it weird that the level of distortion varies with the equipment used?

BTW, Stereophile's John Atkinson used the song in a talk about loudness and dynamics (article), so it can't be too bad a test track. Worst case you just have to neglect the distortion (it's a very short burst).

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RE: Just a Little Distortin' (max input RMS level?)

I can't see how any of the above tells you anything - you have a lot of variables going on.

Different CD players can output at slightly different levels and you don't know if your WAV rip is the same as the CD layer of a SACD. 

 

 

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RE: Just a Little Distortin' (max input RMS level?)

DocG wrote:

BigH wrote:

There is clipping on that recording, Shelby did not want it removing she wanted a live type feel or something, so its on the recording, so maybe not the best test track?

But isn't it weird that the level of distortion varies with the equipment used?

BTW, Stereophile's John Atkinson used the song in a talk about loudness and dynamics (article), so it can't be too bad a test track. Worst case you just have to neglect the distortion (it's a very short burst).

 

The clipping is only on one or 2 notes. Maybe thye used teh SACD which does not have it? Different systems will be more or less revealing. 

DocG's picture
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RE: Just a Little Distortin' (max input RMS level?)

MakkaPakka wrote:

I can't see how any of the above tells you anything - you have a lot of variables going on.

Different CD players can output at slightly different levels and you don't know if your WAV rip is the same as the CD layer of a SACD. 

i just mailed the dealer and asked him to try the Burmester - Devialet combo, while varying the maximum input RMS level of the amp (which can be done thru software). So if he has the time to do it, we'll know soon enough.

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RE: Just a Little Distortin' (max input RMS level?)

DocG wrote:

i just mailed the dealer and asked him to try the Burmester - Devialet combo, while varying the maximum input RMS level of the amp (which can be done thru software). So if he has the time to do it, we'll know soon enough.

Got a mail from the dealer. He did the test with different transports feeding the Devialet. The distortion was only heard with the Burmester, and could be completely eliminated when he lowered the input gain on the amp. So it looks like the distortion is indeed provoqued by a "gain-mismatch" between the source and the amp. As I experienced this with several other source-amp combos, I think it's something to take into account when putting a system together... Which makes "Just a Little Lovin' " an even better test track than I thought it was! Smile

Then again, maybe there is a way around it, using attenuators and stuff. If anyone knows what I'm now talking about (I don't!), feel free to pop in and educate me!

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RE: Just a Little Distortin' (max input RMS level?)

If the clipping is on the original recording, is it a good thing that the amp is covering this up, what else is it not revealing?

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RE: Just a Little Distortin' (max input RMS level?)

BigH wrote:

If the clipping is on the original recording, is it a good thing that the amp is covering this up, what else is it not revealing?

Out of interest: why do you think the clipping was on the original recording? What is your source? It looks unlikely that John Atkinson, giving a lecture on loudness and the dynamic range a CD can produce, would have his audience listen to a CD of a clipping recording to make his point...

IMO, this song uses (close to) the maximum dynamic range a CD can cope with, hence it shows a mismatch in gain (output source higher than input amp) if there is any. If anyone able to use Audacity (Steve,  you there?) would pop in, it would be easy to distinguish what happens. I don't think anything is being covered up (just my opinion, of course).

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RE: Just a Little Distortin' (max input RMS level?)

I read about it one several forums, I think Steve Hoffman was one, as I said earlier Shelby Lynne was asked about it and she said she wanted it left as recorded for a live feel or something similar.

 

Here is one: http://forums.naimaudio.com/topic/gross-distortion-on-just-a-little-lovin-by-shelby-lynne

Here: http://www.sa-cd.net/showtitle/7997

 

As for DR is not bad for a modern cd but highest track is only 13: http://www.dr.loudness-war.info/details.php?id=19050

If you want DR try Steve Earle - Copperhead Road thats about 17.

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RE: Just a Little Distortin' (max input RMS level?)

BigH wrote:

I read about it one several forums, I think Steve Hoffman was one, as I said earlier Shelby Lynne was asked about it and she said she wanted it left as recorded for a live feel or something similar.

Here is one: http://forums.naimaudio.com/topic/gross-distortion-on-just-a-little-lovin-by-shelby-lynne

Here: http://www.sa-cd.net/showtitle/7997

OK, thanks for the links!

It is still weird though that the clipping varies with different CD transports and with varying the input gain of the amplifier...

But I'll leave it there! Cheers!