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'Normalization' of PCM audio - subjectively benign?
RockFan
post Aug 30 2006, 01:47
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Hi All,

A thread back in March discussed whether normalization of WAV files is 'lossy', and I remember that no-one thought to point out that operative word is actually 'destructive'.

Digital processing of PCM audio such as normalization, compression (or expansion), equalisation, etc' is 'destructive', not 'lossy', although both mean 'irreversable'. It has to be said, this seems as much a matter of semantics or even philosophy as much as exact engineering terminology.

Anyway, this is of some interest to me, I'm using a 24-bit ADC to record from vinyl (and taking it pretty seriously as an archiving project - I get one shot at some discs, so I want to do it right), and as it happens there is insufficient gain on the line from the phono-amp I'm using to it to get close to 0dB with some discs, many peak at -6, -8, even -12 dB.

However, even -20 dB or more in 24 bits is greater than 16-bits of resolution. A 24-bit recording which peaks at, say, -16dB, can be 'normalized' to 0dB, and will *still* have information below digital silence in 16-bits, and ideally require dither on conversion.

Obviously I could use a preampifier in addition to the phono-stage to get around the level issues, but I'd rather keep to the 'minimal' signal path I'm using now.

What I'd like to ask people here is; in their experience, is normalization completely 'benign', sonically? Are the algoritms used in different applications much the same, or are some better than others?

R.
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AndyH-ha
post Sep 1 2006, 04:55
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I don't now if everything he says is as nonsensical, but those graphs are made by plotting sample point amplitudes and drawing straight lines between them. That's about as meaningful as measuring temperature every hour and believing that the variations show that infinitely fast temperature shifts have occurred between one measurement and the next.
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RockFan
post Sep 1 2006, 11:45
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QUOTE (AndyH-ha @ Aug 31 2006, 19:55) *
I don't now if everything he says is as nonsensical, but those graphs are made by plotting sample point amplitudes and drawing straight lines between them. That's about as meaningful as measuring temperature every hour and believing that the variations show that infinitely fast temperature shifts have occurred between one measurement and the next.


Groan. So you're saying that some or most if what he says is "nonsensical"?

He discusses the use of over-sampling/digital-filtering further down the page.

Comparing an audio waveform to room-temparature variation is bit of stretch, isn't it? Actually, come to think of it, I suppose a bomb going off could generate a flash of a few milliseconds.

There are many instruments (for e.g. almost any muted brass) which generate edges much faster than CD could ever hope to follow accurately.

edit >> actually, before the pedants weigh in, more correctly, they have ultasonic content which is extremely problematic at 16/44 . Muted cornet generates substantial pressure levels at over 40, even 50 KHz (7th harmonic and beyond), and these are not subtle overtones.

That we can't hear them as discreet components, or a recording system 'band limits' or low-passes at the limit of human hearing is irrelevent, they are intrinsic to the shape of the captured waveform inside the audio band, just as they are to a squarewave.

Interestingly, only non-OS DACs play them back 'accurately' (both examples, muted brass and squarewaves) because they inflict no ringing or phase-shifting as digital filters do.

This post has been edited by RockFan: Sep 1 2006, 12:28
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Posts in this topic
- RockFan   'Normalization' of PCM audio - subjectively benign?   Aug 30 2006, 01:47
- - Mike Giacomelli   Theres nothing worth recording anywhere near 120dB...   Aug 30 2006, 02:22
|- - RockFan   The thing is, I don't want to end up with CDR...   Aug 30 2006, 02:56
|- - Mike Giacomelli   QUOTE (RockFan @ Aug 29 2006, 18:56) The ...   Aug 30 2006, 03:18
|- - RockFan   QUOTE (Mike Giacomelli @ Aug 29 2006, 18...   Aug 30 2006, 03:35
|- - Mike Giacomelli   QUOTE (RockFan @ Aug 29 2006, 19:35) QUOT...   Aug 30 2006, 03:41
|- - RockFan   QUOTE (Mike Giacomelli @ Aug 29 2006, 18...   Aug 30 2006, 04:16
|- - Axon   QUOTE (RockFan)Analogue sources have no '0dB...   Aug 30 2006, 08:25
- - Hollunder   At least peak normalisation should be more or less...   Aug 30 2006, 02:46
|- - RockFan   I use replay gain for my own listening (with Fooba...   Aug 30 2006, 03:03
- - AndyH-ha   Yes, it is completely "benign," at leas...   Aug 30 2006, 03:01
|- - RockFan   I guess that's the conundrum - add a pre-amp o...   Aug 30 2006, 03:19
|- - Mike Giacomelli   QUOTE (RockFan @ Aug 29 2006, 19:19) I gu...   Aug 30 2006, 03:28
- - jlt   QUOTE I have thought of building a simple opamp ba...   Aug 30 2006, 03:32
- - AndyH-ha   QUOTE In the context of straight LP to CD transfer...   Aug 30 2006, 03:59
|- - RockFan   QUOTE (AndyH-ha @ Aug 29 2006, 18:59...   Aug 30 2006, 04:30
- - AndyH-ha   Unless you used a very poor program, the only unde...   Aug 30 2006, 08:54
|- - cliveb   QUOTE (AndyH-ha @ Aug 30 2006, 08:54...   Aug 30 2006, 12:11
|- - RockFan   That's very useful info, Clive, thanks for sha...   Aug 30 2006, 15:11
|- - cliveb   QUOTE (RockFan @ Aug 30 2006, 15:11) Howe...   Aug 30 2006, 15:47
|- - RockFan   QUOTE (cliveb @ Aug 30 2006, 06:47) And t...   Aug 30 2006, 16:16
|- - 2Bdecided   QUOTE (RockFan @ Aug 30 2006, 16:16) But ...   Aug 30 2006, 17:10
||- - RockFan   QUOTE (2Bdecided @ Aug 30 2006, 08:10) It...   Aug 30 2006, 17:41
||- - SebastianG   QUOTE (RockFan @ Aug 30 2006, 18:41) It h...   Aug 31 2006, 18:16
||- - RockFan   QUOTE (SebastianG @ Aug 31 2006, 09:16) E...   Aug 31 2006, 23:58
||- - SebastianG   QUOTE (RockFan @ Sep 1 2006, 00:58) Yes T...   Sep 1 2006, 09:47
||- - RockFan   QUOTE (SebastianG @ Sep 1 2006, 00:47) We...   Sep 1 2006, 10:43
||- - SebastianG   QUOTE (RockFan @ Sep 1 2006, 11:43) If yo...   Sep 1 2006, 12:57
||- - RockFan   QUOTE (SebastianG @ Sep 1 2006, 03:57) Bu...   Sep 1 2006, 14:02
||- - SebastianG   QUOTE (RockFan @ Sep 1 2006, 15:02) QUOTE...   Sep 1 2006, 15:34
|- - cliveb   QUOTE (RockFan @ Aug 30 2006, 16:16) But ...   Aug 30 2006, 18:16
|- - RockFan   QUOTE (cliveb @ Aug 30 2006, 09:16) So, j...   Aug 30 2006, 18:41
|- - greynol   QUOTE (RockFan @ Aug 30 2006, 10:41) Ther...   Aug 30 2006, 18:46
|- - RockFan   QUOTE (greynol @ Aug 30 2006, 09:46) QUOT...   Aug 30 2006, 18:54
- - AndyH-ha   I guess there is a difference in subject matter. I...   Aug 30 2006, 09:12
- - 2Bdecided   Maybe I can put it this way... If the noise floor...   Aug 30 2006, 10:36
- - 2Bdecided   I'm glad you've critiqued that, Clive. Th...   Aug 30 2006, 13:44
- - Axon   What David said. Once you move to spectral measure...   Aug 30 2006, 14:32
|- - GeSomeone   QUOTE (Axon @ Aug 30 2006, 15:32) If you ...   Aug 31 2006, 17:34
|- - greynol   QUOTE (GeSomeone @ Aug 31 2006, 09:34) I ...   Aug 31 2006, 17:50
- - jlt   off topic: this thread is "bookmarked"...   Aug 30 2006, 15:06
- - Axon   Just to put some hard numbers down on the signal-t...   Aug 30 2006, 18:07
|- - RockFan   I have to say, as something of a vinyl die-hard, I...   Aug 30 2006, 22:28
|- - 2Bdecided   QUOTE (RockFan @ Aug 30 2006, 17:41) QUOT...   Aug 31 2006, 13:11
|- - RockFan   QUOTE (2Bdecided @ Aug 31 2006, 04:11) QU...   Aug 31 2006, 16:34
|- - greynol   QUOTE (RockFan @ Aug 31 2006, 08:34) And ...   Aug 31 2006, 16:43
|- - 2Bdecided   QUOTE (RockFan @ Aug 31 2006, 16:34) QUOT...   Aug 31 2006, 17:18
|- - RockFan   QUOTE (2Bdecided @ Aug 31 2006, 08:18) Yo...   Aug 31 2006, 23:37
|- - Mike Giacomelli   QUOTE (RockFan @ Aug 31 2006, 15:37) Nyqu...   Sep 1 2006, 01:00
||- - RockFan   Nyquist's 'theorem' applys to constant...   Sep 1 2006, 02:04
||- - Mike Giacomelli   QUOTE (RockFan @ Aug 31 2006, 18:04) Nyqu...   Sep 2 2006, 06:20
||- - RockFan   QUOTE (Mike Giacomelli @ Sep 1 2006, 21:2...   Sep 2 2006, 13:11
||- - Mike Giacomelli   QUOTE (RockFan @ Sep 2 2006, 05:11) QUOTE...   Sep 2 2006, 21:57
||- - RockFan   QUOTE (Mike Giacomelli @ Sep 2 2006, 12:5...   Sep 2 2006, 22:39
||- - kjoonlee   QUOTE (RockFan @ Sep 3 2006, 06:39) Compa...   Sep 3 2006, 02:16
|- - 2Bdecided   QUOTE (RockFan @ Aug 31 2006, 23:37) Nyqu...   Sep 1 2006, 11:42
|- - RockFan   QUOTE (2Bdecided @ Sep 1 2006, 02:42) QUO...   Sep 1 2006, 12:03
- - jlt   QUOTE 2. Dither down to 16 bit, then normalise at ...   Aug 30 2006, 18:48
|- - greynol   QUOTE (jlt @ Aug 30 2006, 10:48) QUOTE 2....   Aug 30 2006, 18:53
- - Axon   Enough is right! This is getting too pedantic ...   Aug 30 2006, 18:59
|- - RockFan   QUOTE (Axon @ Aug 30 2006, 09:59) Enough ...   Aug 30 2006, 19:19
|- - cliveb   QUOTE (RockFan @ Aug 30 2006, 19:19) A pe...   Aug 30 2006, 19:38
|- - RockFan   QUOTE (cliveb @ Aug 30 2006, 10:38) All I...   Aug 30 2006, 20:37
|- - cliveb   QUOTE (RockFan @ Aug 30 2006, 20:37) Poss...   Aug 30 2006, 20:52
- - jlt   QUOTE Ok, before we start listening with our eyesu...   Aug 30 2006, 19:19
- - greynol   I'll leave you audiophiles alone now.   Aug 30 2006, 19:20
- - jlt   QUOTE (greynol @ Aug 30 2006, 12:20) I...   Aug 30 2006, 19:25
- - AndyH-ha   Since the forum has apparently been offline much o...   Aug 31 2006, 06:36
- - jlt   QUOTE What do you think? http://www.hydrogenaudio...   Aug 31 2006, 15:37
- - jlt   QUOTE I'll leave you audiophiles alone now. yo...   Aug 31 2006, 16:47
- - greynol   QUOTE (jlt @ Aug 31 2006, 08:47) QUOTE I...   Aug 31 2006, 16:49
- - AndyH-ha   QUOTE the link posted by AndyH-ha from "some ...   Aug 31 2006, 21:50
- - jlt   QUOTE but what did I do?nothing wrong AndyH-ha.( i...   Aug 31 2006, 22:42
|- - 2Bdecided   QUOTE (jlt @ Aug 31 2006, 22:42) QUOTE bu...   Sep 1 2006, 11:08
- - AndyH-ha   I see. While everyone has their biases, the unques...   Aug 31 2006, 23:21
- - jlt   @ AndyH-ha QUOTE most people who uses the AudioMas...   Aug 31 2006, 23:53
- - jlt   QUOTE And the simple fact is that audio is data......   Sep 1 2006, 01:11
- - AndyH-ha   Digital data isn't music, or any kind audio, b...   Sep 1 2006, 01:44
- - AndyH-ha   I don't now if everything he says is as nonsen...   Sep 1 2006, 04:55
|- - RockFan   QUOTE (AndyH-ha @ Aug 31 2006, 19:55...   Sep 1 2006, 11:45
|- - 2Bdecided   QUOTE (RockFan @ Sep 1 2006, 11:45) There...   Sep 1 2006, 12:39
|- - RockFan   QUOTE (2Bdecided @ Sep 1 2006, 03:39) Han...   Sep 1 2006, 13:36
|- - 2Bdecided   QUOTE (RockFan @ Sep 1 2006, 13:36) Wheth...   Sep 1 2006, 16:52
|- - RockFan   QUOTE (2Bdecided @ Sep 1 2006, 07:52) Wha...   Sep 2 2006, 13:49
- - 2Bdecided   It's proven in those threads! EDIT: Havin...   Sep 1 2006, 12:06
- - AndyH-ha   English is a hard language to communicate in. Not ...   Sep 1 2006, 12:17
- - jlt   hi all (again) why cd players have LPF in the ...   Sep 1 2006, 14:37
- - kjoonlee   This is absurd. Of course filtering (which change...   Sep 2 2006, 14:30
|- - RockFan   QUOTE (kjoonlee @ Sep 2 2006, 05:30) This...   Sep 2 2006, 14:53
|- - kjoonlee   QUOTE (RockFan @ Sep 2 2006, 22:53) QUOTE...   Sep 2 2006, 15:39
|- - RockFan   QUOTE (kjoonlee @ Sep 2 2006, 06:39) QUOT...   Sep 2 2006, 17:28
|- - kjoonlee   QUOTE (RockFan @ Sep 3 2006, 01:28) Subje...   Sep 2 2006, 17:51
|- - RockFan   QUOTE (kjoonlee @ Sep 2 2006, 08:51) No, ...   Sep 2 2006, 18:26
|- - kjoonlee   QUOTE (RockFan @ Sep 3 2006, 02:26) But a...   Sep 2 2006, 19:21
|- - Steve999   Exactly. QUOTE (kjoonlee @ Sep 2 2006, 10...   Sep 3 2006, 01:06
- - kjoonlee   And a change in the spectrogram is a change in the...   Sep 2 2006, 16:49
- - jlt   QUOTE a change in shape does not imply a change in...   Sep 2 2006, 18:00
|- - kjoonlee   QUOTE (jlt @ Sep 3 2006, 02:00) QUOTE a c...   Sep 2 2006, 18:08
- - jlt   kjoonlee, a.audition1.5 is one good editor to do t...   Sep 2 2006, 18:34
- - jlt   QUOTE I don't think my soundcard can play 30kH...   Sep 2 2006, 21:14
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