Hi Eric: 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 > mailto:[log in to unmask] > http://www.TheAudioArchive.com > Disc and Tape Audio Transfer Services and Preservation Consulting >