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Re: mastering for cheap cd players

Subject: Re: mastering for cheap cd players
From: Eric Benjamin <>
Date: Tue, 10 Jan 2006 11:16:43 -0800 (PST)
While the distortion is easy to hear, as Dan Dugan
said, the reason that it's hard to see is that the
resampling process of running the signal through
another stage of ADC (regardless of how good the
quality is) changes the waveform shape a lot, due to
the elimination of ultrasonic components which are the
ones primarily determining the waveform shape.

I'd like to follow up on this further, but not on the
list.  Rich -I'll contact you off-list.  BTW, it may
have sounded like I didn't believe your desription of
the fault.  Not at all!  I'm just curious.

eric

--- Rob Danielson <> wrote:

> Thanks for the plausible explanation! You're right,
> my waveform app 
> shows a clip at two magnification scales but it
> measures a peak of 
> 94%.  I'm hearing three, pronounced, moments of
> distortion that sound 
> like chain shaking in the louder, CD player call and
> two of these, 
> but softer in the original. As the 2nd half of the
> file was produced 
> from the CD player's analog amp/output passing
> through another A-D, I 
> guess its hard to tell where the exaggeration is
> coming from exactly. 
> The distortion is too wide to address with EQ.
> Surgical gain 
> reductions were not very successful either. The
> harshness of the 
> undistorted portions are responsive to EQ (e.g.
> mastering).
> 
> The softer call seems great so Rich has a simple
> work-around. I guess 
> there could be several reasons the softer call
> escaped distortion. 
> Dan, do you think that a lower record gain would
> have eliminated this 
> type of distortion or is it likely to be more
> complicated? Rob D.
> 
> = = =
> 
> At 6:22 AM -0800 1/10/06, Dan Dugan wrote:
> >  >  > http://home.comcast.net/~richpeet/0659.wav
> >
> >It may be a type of analog audio distortion called
> slew rate
> >distortion. It affects high-frequency, high-level
> material, adding a
> >lower-frequency rasp to it. The peaks aren't
> clipped, but the slopes
> >are flattened out at an angle, i.e. a sine wave is
> changed into a
> >triangle wave. Easy to hear, hard to see on a
> complex waveform.
> >
> >-Dan Dugan
> >
> 
> -- 
> Rob Danielson
> Film Department
> University of Wisconsin-Milwaukee
> 
> 
> "Microphones are not ears,
> Loudspeakers are not birds,
> A listening room is not nature."
> Klas Strandberg 
> Yahoo! Groups Links
> 
> 
>     
> 
>  
> 
> 
> 



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