Peter Galbavy;596801 Wrote: > 10dB is a factor of 10. 20dB is 100. 23dB is actually as close to a > ratio of 200 as you can get with whole numbers. > > You perhaps mean 6db of SPL is a factor of 2 in loudness terms ? > Different thing here.
No. In digital recording/playback, each "bit" is worth just over 6dB of dynamic range/SNR. 16 bits = approx 96dB max RANGE (not level!) 24 dB = approx 144dB max RANGE (not level!) This is not directly related to SPL or any other absolute "level", because we are strictly in the digital domain here, not the analogue one. I am not measuring anything with an SPL meter - I am looking at the digital sample data and the samples are all unnecessarily lower in value than they could be. We are talking about the relative levels between the quietest and loudest sounds that can be captured at the same time. Full-scale in both 16 and 24 bit represents the same nominal "level" when played back through the same DAC. Just above "Zero level" - a single "bit" - would in theory represent -96dB and -144dB respectively, but in practice 24-bit only gets down to -120dB at its very, very best. Most systems are unable to resolve much over -108dB. The recording in question has a peak level of -23dB, meaning that it has nearly "4 bits" of SNR/Dynamic range unused. As a consequence you have to turn up the analogue replay level quite a bit to compensate and get it back to a more normal replay level. This raises the level of the background noise too... hence the loss of SNR. The signal is peaking too close to the noise floor. This is why I am saying it is incorrectly mastered - as far as level is concerned. So, instead of this recording having a potential playback dynamic range/SNR of 120dB (assuming a really good ADC was used and a really good DAC too) it is in fact restricted to less than 100dB... This is hardly maximising the capabilities of 24-bit recording/playback! -- Phil Leigh You want to see the signal path BEFORE it gets onto a CD/vinyl...it ain't what you'd call minimal... Touch(wired/XP) - TACT 2.2X (Linear PSU) + Good Vibrations S/W - MF Triplethreat(Audiocom full mods) - Linn 5103 - Aktiv 5.1 system (6x LK140's, ESPEK/TRIKAN/KATAN/SEIZMIK 10.5), Pekin Tuner, Townsend Supertweeters, Blue Jeans Digital,Kimber Speaker & Chord Interconnect cables Kitchen Boom, Outdoors: SB Radio, Harmony One remote for everything. ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=84091 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
