The way I interpret this is, under typical conditions if you do a FLAT transfer of a grooved disk at
24-bits, and then EQ in the digital realm (EQ = compensate for the recording curve), you end up with
more or less CD resolution as far as bit-depth. And if you went with a conservative transfer level,
where peak level upon EQ compensation is somewhere between -6dBfs and digital zero, you then are
right in the realm of CD resolution (6dB equalling about 2 bits, so net bits are about 16). Is this
a correct interpretation?
-- Tom Fine
----- Original Message -----
From: "Eric Jacobs" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, March 10, 2010 4:28 PM
Subject: Re: [ARSCLIST] Disc EQ in the digital domain
> On Wednesday, March 10, 2010 8:44 AM, Jim Sam wrote:
>> On Tue, Mar 9, 2010 at 6:42 PM, Eric Jacobs wrote:
>>> Transfering FLAT will cost you about 6-7 bits of dynamic
>>> range - an audible loss.
>> 36-42 dB*? ~10-12 is more like it, which is two bits max.
>> That leaves 22 bits, which is more than adequate.
> Hi Jim,
> Just a thumbnail calculation on word length loss for two common EQs:
> RIAA boost = 19.27 dB @ 20 Hz
> RIAA cut = 19.62 dB @ 20,000 Hz
> RIAA dynamic range lost = 38.89 dB
> RIAA approximate word length loss with FLAT EQ transfer = 6.5 bits
> NAB boost = 19.85 dB @ 20 Hz
> NAB cut = 21.52 dB @ 20,000 Hz
> NAB dynamic range lost = 41.37 dB
> NAB approximate word length loss with FLAT EQ transfer = 6.8 bits
> To the extent that fractional bits exist. <smile>
> Keep in mind that this is word length loss due to a FLAT transfer,
> where the bass boost is lost, and extra headroom is needed to
> accomodate the lack of treble cut.
> Eric Jacobs
> The Audio Archive, Inc.
> tel: 408.221.2128
> fax: 408.549.9867
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> Disc and Tape Audio Transfer Services and Preservation Consulting