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Most 'true' way to de-emphasize CD image, Remove pre-emphasis - possible and best ways?
EvilMax
post Aug 2 2008, 13:46
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Hello!

Have a question related to de-emphasizing of images of audio CDs mastered with pre-emphasis. What I've already found on this topic:

1. Using Waves Q10 plugin. But it seems to me that equalizer plugin is not the best way to achieve originally mastered sound.
2. Using foobar2000 convolver with Waves_De-Emphasis pulses. Don't know anythig good/bad for this way.

So does anybody knows what way is 'true' to de-emphasize wave file?

PS: I know that using EAC or K3b to burn CD and delegate de-emphasizing to CD player will solve issue. But for some reasons I need to have images on my PC and ability to play them or several tracks on players that don't support 'pre' flag.
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sbooth
post Aug 2 2008, 16:37
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CD de-emphasis was originally designed to be done in the analog domain. If you want to do it digitally the best way is to process the file at 24 bits (or higher) then either leave it at the higher bit depth or dither it back to 16. If you process it at 16 bits you will definitely lose fidelity. Unfortunately I'm not familiar enough with the SoX internals to know how its effects are applied.
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Porcus
post Feb 24 2010, 08:15
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QUOTE (sbooth @ Aug 2 2008, 16:37) *
If you want to do it digitally the best way is to process the file at 24 bits (or higher) then either leave it at the higher bit depth or dither it back to 16. If you process it at 16 bits you will definitely lose fidelity.


Well, I just tried that. Converted to 24 and SoX-deemph'ed the files.
Guess what, they became > 50 % larger. Not by converting to 24 bits (FLAC compresses away the padded zeroes at little extra space cost), but by the deemphasis filter.

Which is fairly strange, as the actual information is the same, but:
Do not the two facts combined, that (I) the EQ curve only hits appr. 10dB (< 2 bits, or just above 10 %) and (II) the files seem to grow by 50 %, (mildly) suggest that SoX de-emph introduces digital noise below the 18th bit, which actually should be dithered away for fidelity?


(SoX version 14.1.0, libflac version 1.2.1, flac -8 used)

This post has been edited by Porcus: Feb 24 2010, 08:16


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Posts in this topic
- EvilMax   Most 'true' way to de-emphasize CD image   Aug 2 2008, 13:46
- - pdq   Are they still making CDs with pre-emphasis, or ar...   Aug 2 2008, 14:46
|- - EvilMax   QUOTE (pdq @ Aug 2 2008, 16:46) Are they ...   Aug 2 2008, 15:38
||- - M   QUOTE (EvilMax @ Aug 2 2008, 10:38) Egor,...   Aug 2 2008, 15:51
|||- - EvilMax   QUOTE (M @ Aug 2 2008, 17:51) QUOTE (Evil...   Aug 2 2008, 16:22
||- - Egor   QUOTE (EvilMax @ Aug 2 2008, 21:38) Egor,...   Aug 2 2008, 19:08
||- - EvilMax   It is all very interesting, thank you for informat...   Aug 2 2008, 19:32
||- - Egor   QUOTE (EvilMax @ Aug 3 2008, 01:32) Inter...   Aug 2 2008, 19:41
||- - EvilMax   QUOTE (Egor @ Aug 2 2008, 21:41) QUOTE (E...   Aug 2 2008, 20:04
|- - Porcus   QUOTE (pdq @ Aug 2 2008, 14:46) Are they ...   Feb 24 2010, 08:05
|- - Porcus   QUOTE (Porcus @ Feb 24 2010, 09:05) QUOTE...   Apr 29 2012, 16:28
- - Egor   You can de-emphasize using sox (a command line pro...   Aug 2 2008, 15:17
- - sbooth   CD de-emphasis was originally designed to be done ...   Aug 2 2008, 16:37
|- - Porcus   QUOTE (sbooth @ Aug 2 2008, 16:37) If you...   Feb 24 2010, 08:15
- - Surfi   Using Waves Q10 too. Tried Sox before but did hear...   Aug 2 2008, 16:57
|- - greynol   QUOTE (Surfi @ Aug 2 2008, 08:57) Using W...   Aug 2 2008, 18:47
|- - Surfi   QUOTE (greynol @ Aug 2 2008, 19:47) How i...   Aug 3 2008, 16:17
|- - bandpass   QUOTE (Surfi @ Aug 3 2008, 15:17) Either ...   Aug 8 2008, 18:55
|- - markanini   QUOTE (bandpass @ Aug 8 2008, 18:55) QUOT...   Aug 10 2008, 02:58
|- - Surfi   QUOTE (markanini @ Aug 10 2008, 03:58) th...   Aug 10 2008, 11:00
- - benski   Yes, de-emphasis is meant to be done in the analog...   Aug 2 2008, 18:38
|- - Glenn Gundlach   QUOTE (benski @ Aug 2 2008, 09:38) Yes, d...   Aug 2 2008, 19:00
- - M   According to the changelog, the deemphasis filter ...   Aug 2 2008, 20:03
- - Sebastian Mares   Did anyone check how well iTunes deemphasizes CDs?   Aug 3 2008, 11:08
- - markanini   I have tried Sox and WaveEmph and comparing the sp...   Aug 3 2008, 12:02
|- - tot   sox with --plot option and deemph will plot the fi...   Aug 3 2008, 15:40
- - Aquares   Tested with Denon Audio Technical CD (1984), Track...   Nov 13 2009, 20:15
|- - Wombat   Never saw someone offering such measurements, than...   Nov 14 2009, 02:19
|- - Kees de Visser   QUOTE (Wombat @ Nov 14 2009, 02:19) even ...   Nov 14 2009, 15:29
|- - Aquares   QUOTE (Wombat @ Nov 14 2009, 03:19) One t...   Nov 15 2009, 22:07
- - krabapple   Measured difference of 0.2 dB is not bloody likely...   Nov 15 2009, 06:07
|- - Kees de Visser   QUOTE (krabapple @ Nov 15 2009, 06:07) Me...   Nov 15 2009, 12:19
- - Wombat   I tried one more thing. Seems really like the cre...   Nov 16 2009, 17:23
- - pdq   ANY operation on the data other than scaling by ex...   Feb 24 2010, 12:51
|- - Porcus   QUOTE (pdq @ Feb 24 2010, 12:51) ANY oper...   Feb 24 2010, 19:42
|- - DVDdoug   QUOTE (Porcus @ Feb 24 2010, 10:42) QUOTE...   Feb 24 2010, 20:48
- - pdq   It should make little difference to a lossy encode...   Feb 24 2010, 20:27
- - greynol   So long as sox does the internal math at a higher ...   Feb 24 2010, 20:57
|- - Porcus   @ DVDdoug and pdq: The argument on the number of ...   Feb 24 2010, 21:34
|- - greynol   QUOTE (Porcus @ Feb 24 2010, 12:34) Well ...   Feb 24 2010, 21:48
|- - pdq   QUOTE (Porcus @ Feb 24 2010, 16:34) @ DVD...   Feb 24 2010, 21:50
||- - Porcus   QUOTE (pdq @ Feb 24 2010, 21:50) Besides,...   Feb 24 2010, 22:16
|- - googlebot   QUOTE (Porcus @ Feb 24 2010, 22:34) @ DVD...   Oct 26 2010, 09:58
|- - knutinh   QUOTE (googlebot @ Oct 26 2010, 10:58) Th...   Oct 26 2010, 12:14
|- - googlebot   As said, it's already all in post #36. Digit...   Oct 26 2010, 13:45
|- - knutinh   QUOTE (googlebot @ Oct 26 2010, 14:45) As...   Oct 26 2010, 14:25
|- - googlebot   QUOTE (knutinh @ Oct 26 2010, 15:25) This...   Oct 26 2010, 15:08
|- - Porcus   QUOTE (googlebot @ Oct 26 2010, 16:08) QU...   Oct 27 2010, 10:14
|- - googlebot   QUOTE (Porcus @ Oct 27 2010, 11:14) (Are ...   Oct 27 2010, 11:04
|- - 2Bdecided   QUOTE (googlebot @ Oct 27 2010, 11:04) Ro...   Oct 27 2010, 15:35
|- - googlebot   QUOTE (2Bdecided @ Oct 27 2010, 16:35) go...   Oct 27 2010, 17:33
- - Wombat   For the ones that want a VST solution to do some d...   Oct 11 2010, 16:56
- - Wombat   Well, not the most interesting thing but i wanted ...   Oct 26 2010, 01:57
- - knutinh   Now we are getting somewhere. So I should have sta...   Oct 26 2010, 16:08
- - 2Bdecided   I think it's far simpler than you think. Cons...   Oct 26 2010, 16:42
|- - knutinh   QUOTE (2Bdecided @ Oct 26 2010, 17:42) 2....   Oct 26 2010, 18:32
- - 2Bdecided   Yes, but the design is such that it works "be...   Oct 27 2010, 10:19
- - knutinh   I guess that whatever per-channel correlation is i...   Oct 27 2010, 12:38
|- - googlebot   Why exactly 8?   Oct 27 2010, 12:42
|- - knutinh   QUOTE (googlebot @ Oct 27 2010, 13:42) Wh...   Oct 27 2010, 15:42
|- - Porcus   QUOTE (knutinh @ Oct 27 2010, 16:42) QUOT...   Oct 27 2010, 20:33
- - Porcus   FWIW, I checked this with multiple lossless encode...   Oct 28 2010, 01:09
|- - Porcus   For reference: 7 761 846 272 bytes: flac -8 (24 b...   Oct 28 2010, 01:17
- - Bullit   I haven't found much info on emphasis. From wh...   Oct 28 2010, 03:45
|- - Porcus   QUOTE (Bullit @ Oct 28 2010, 04:45) I hav...   Oct 28 2010, 10:05
|- - Bullit   QUOTE (Porcus @ Oct 28 2010, 10:05) QUOTE...   Nov 1 2010, 04:09
|- - Glenn Gundlach   QUOTE (Bullit @ Oct 31 2010, 19:09) QUOTE...   Nov 1 2010, 05:18
- - greynol   Have you tried our wiki? It's generally the f...   Nov 1 2010, 05:10
- - Bullit   QUOTE (greynol @ Nov 1 2010, 05:10) Have ...   Nov 1 2010, 19:22
- - lvqcl   [misread]   Nov 1 2010, 19:36
- - greynol   QUOTE (Bullit @ Nov 1 2010, 11:22) I look...   Nov 1 2010, 19:43


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