RE: Thanks!

Posted by Tony Lauck (A) on March 25, 2012 at 08:08:28

In Reply to: RE: Thanks! posted by Iron Knee on March 24, 2012 at 22:50:27:

"-48dB peaks in 24 bit is the same resolution as CD at full scale."

This assumes that the -48 dB digitization was done nearly perfectly. One might achieve an approximation to this if one were to start with a proper digitization and reduce it arithmetically, since this would get a result that was correct to within 1 least significant bit. However, if one were to feed a low level analog signal to an ADC the result would not be what you said unless the analog noise in the converter was below -144 dB. This is far better from any ADC that I've heard of. ADCs tend to have more noise than DACs and the best current DAC chips are at about 135 dB and this is under laboratory conditions. A complete DAC running in a box connected to a system will not have this performance.

I've seen 16 bit digital recordings with peaks as low as -30 dBfs that ended up sounding acceptable (if not excellent) after they were boosted digitally to a reasonable level. This will depend on the converters used, i.e. for decent results they would have to have no gross non-linearity at low levels and no loud hum, birdies or other spurious signals, and have been properly dithered. (At this level turning up the analog volume on the playback of the unboosted file would be a very bad idea. If there were enough gain to get reasonably loud music than any glitch might blow up some gear.) Of course there will be a lot of noise, but if the original was noisy to start with this might not matter too much. My comments applied to some recordings that I was given that had been recorded or transferred digitally at very low levels. They were what they were. If I had been doing a digital transfer and gotten these results I would have redone them after thinking carefully about how and why I had made such a mistake.

Tony Lauck

"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar

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Follow Ups Full Thread

Topic - How hard should I strive to get maximum signal? - Phil_in_CA 18:24:04 03/24/12 (21)

Look for the Max Signal Level Prior to Digitizing.................... - Todd Krieger 22:31:40 03/24/12 (1)

RE: Look for the Max Signal Level Prior to Digitizing.................... - Phil_in_CA 09:42:50 03/25/12 (0)

don't record hot in digital - Joe Murphy Jr 21:07:33 03/24/12 (9)

That's what I've heard and read, but ... - Dave Pogue 09:10:51 03/26/12 (5)

RE: That's what I've heard and read, but ... - Tony Lauck 10:52:45 03/26/12 (0)

two possibilities - Joe Murphy Jr 09:47:42 03/26/12 (3)

Thanks, just dragged out the owner's manual. - Dave Pogue 11:21:25 03/26/12 (2)

RE: Thanks, just dragged out the owner's manual. - Tony Lauck 13:05:36 03/26/12 (1)

Thanks again, but ... - Dave Pogue 14:23:52 03/26/12 (0)

RE: don't record hot in digital - Tony Lauck 10:04:35 03/25/12 (2)

RE: don't record hot in digital - tom.dennehy 22:10:39 03/25/12 (1)

RE: don't record hot in digital - Tony Lauck 07:46:43 03/26/12 (0)

Thanks! - Phil_in_CA 19:43:22 03/24/12 (4)

RE: Thanks! - Iron Knee 22:50:27 03/24/12 (3)

RE: Thanks! - Tony Lauck 08:08:28 03/25/12 (2)

RE: Thanks! - Iron Knee 10:21:20 03/25/12 (1)

RE: Thanks! - Tony Lauck 11:01:06 03/25/12 (0)

RE: How hard should I strive to get maximum signal? - Tony Lauck 19:36:23 03/24/12 (2)

RE: How hard should I strive to get maximum signal? - tom.dennehy 04:34:49 03/26/12 (1)

Trust but Verify - Tony Lauck 08:03:16 03/26/12 (0)

Any level above -6 dB uses all the bits ... nt - slider 18:43:08 03/24/12 (0)

Follow Ups

RE: Thanks! - Tony Lauck 08:08:28 03/25/12 (2)

RE: Thanks! - Iron Knee 10:21:20 03/25/12 (1)

RE: Thanks! - Tony Lauck 11:01:06 03/25/12 (0)

RE: Thanks!

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