At 11:22 AM -0400 8/23/04, Walter Knapp wrote:
>From: Dan Dugan <>
>
> > ATRAC -does- eliminate the high end, which eliminates a lot of
>> bits--I see what appears to be a signal-dependent variable low-pass
>> around 16K.
Walt wrote:
>You must be working with ATRAC 4. Newer ATRAC it's quite a bit above
>that. Even ATRAC 4 got the high stuff, just dropped the very quiet parts
>of the high stuff. I used to estimate it's dropoff at about the -50dB
>point below the highest levels at that frequency. And if you work that
>over against the normal adult hearing it's not a problem.
>
>ATRAC 4.5, which is what the portadisc has is pretty good up to
>18-20khz, then some slight effect like ATRAC 4 above that. Much less
>than ATRAC 4. I've not examined the even newer ATRAC.
>
I agree Walt. Likely that differences in ATRAC algorithms are
involved. I can detect a delay in my MT-90's (ATRAC 3) response to
greater high end content and then lag after the highs go away. Rob D.
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