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EAC changes the EQ [moderation: only via pre-/de-emphasis], EAC alters sound
TheFodge
post Oct 28 2005, 04:05
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I'm no expert, but I have concluded that EAC in some instances alters the original CD sound when it converts to a wav file. I'm no expert so I can't fully explain why, but I have ears and am sure this is happening. I noticed this when ripping Santana's Beyond Appearances. EAC transforms it by greatly exagerating the high end --- this is very real!!!!!! I have experimented with this CD and noticed that when iTunes converted this CD to a wav file it was much more accurate sounding as compared to the original CD (believe me I am no fan of iTunes which is why I use LAME). So I compared the two different wave forms using a wave editor (e.g. Nero Wave Editor or Cool Edit Pro) and what I found was that the iTunes wav file displayed more narrowly than the EAC wav file. I know EAC is supposed to be an exact copy blah blah blah but can someone explain what's going on here. It may only be an issue with the songs on this album (a sampling of other CDs yielded what appeared to be identical wav forms from EAC and iTunes) but the songs on this Santana album create noticably different wav forms and it has me wondering if this differential exists elsewhere. Anyone?

I HAVE RESOLUTION TO THIS PROBLEM!!....HERE IT IS.
Thanks to all those that posted. This problem only relates to older CD's which were recorded using a now obsolete method called pre-emphasis. If the "Pre-emphasis" column in EAC says YES when you have a CD inserted, then this situation exists. (I didn't even know that the "Pre-Emphasis" column existed in EAC as it was hidden on the far right and I had to shorten the title column in order to see it). I now know to check this column.

If a CD has pre-emphasis, I simply will use iTunes to convert it to a wav and then convert that wav with LAME. EAC was not performing the de-emphasis needed to bring the equalization back to normal but iTunes makes this adjustment.

Thanks again for everyone's help. I once again feel comfortable using the EAC/LAME as my ripper of choice.

This post has been edited by TheFodge: Oct 29 2005, 00:10
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Weird Music Mafi...
post Nov 18 2005, 11:55
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Hi, guys!

I'm collecting classical CDs since the beginning of the CD era.

In my collection of ~ 5000 classical CDs I have discovered some 150 CDs with pre-emphasis so far (1 among ~33 - is this rare???).

Attention: It's often said that only recordings mastered before 1986 use pre-emphasis --> definitely wrong !!!
Some labels do use it just up to date (but not regularily) e.g. Erato and the Swedish label BIS (on almost every second CD) !!!

In short (I can only tell about classical, though) - which labels are suspicious to use it more frequently than others?

I never found any CD by Universal (Deutsche Grammophon, Philips, Decca...), RCA (BMG) or CBS/Sony (but that's no guarantee)
EMI didn't use it after 1987 (but Maazel's Zeffirelli-Otello soundtrack has it - besides this one I only got some CDs from EMI Japan with pre-emph).

Pre-Emph is (still !) used frequently on Supraphon, BIS, Erato, New World Records and other smaller labels - especially from Northern & Eastern Europe.
( I believe you'll find it often, too on smaller jazz labels...)

So pre-emph still remains a serious problem for ripping (because most people simply don't know about it)!
Best puzzles are CDs with mixed pre-emph status (some tracks on the CD have pre-emph, others not!). For a long time I was quite sure such CDs wouldn't exist anyway - but meanwhile I have discovered at least 2 examples of New World Records CDs with mixed status

There's a simple (but precise) free tool available developed by an acoustics engineer (Mr. Ahlersmeyer) to de-emphasize pre-emphasized audio data (so we could do compressing, converting, releasing - all we need afterwards).

It's just great, of course better than the often recommended WAVE 10 band equalizer Q10 - an equalizer can only give an approximation to the de-emphasis curve. Mr. Ahlersmeyer uses exactly the mathematics needed. You need the VB5 runtime libraries installed to your system. The tool is available as freeware here:

http://www.picosound.de/Waveemph100a.zip

Mr. Ahlersmeyer says that the tool wouldn't run under XP --> it does (you have to choose Win98 compatibilty modus though, else you would indeed get an overflow error).

Unfortunately the tool produces an overflow error, too, if the original CD data contains exactly 100% peaks. The only workaroung at the moment would be to normalize to 97% before using the tool...

So - if you want to produce compressed audio from a pre-emphed CD, try the following procedure: smile.gif

1). Open the CD with EAC and figure out if the PRE-Flag is set
2). Extract the digital audio with EAC - > Copy Image & Create CUE Sheet
3). Apply Waveemph100a to the extracted .wav
4). Split the de-empasized WAV to separate tracks with EACs Tool -> Split WAV by CUE Sheet
5). Produce your mp3s (oggs... whatsoever) from the single tracks...

If you want to archive a CD as a whole (for burning later as CD Audio - not for listening on the PC!) it's sufficient to use EACs
- > Copy Image & Create CUE Sheet -> compressed
because EAC produces correct cue-sheets with the Flag PRE lines (many other rippers don't).

Attention: NERO (even V.7) simply ignores the PRE-Flag in an audio cue sheet (even when burning an image) and doesn't set the bit on the burnt audio CD.
So never burn an audio CD image of a CD containing pre-emph with Nero!
(This is a real shame - only if you will be using Nero's plain Copy CD function the PRE-Flags are preserved!). crying.gif
Burning with EAC itself of course will produce perfect copies (I would like to know which alternative burning proggies do evaluate the PRE-Flag of an audio CD cue correctly - please post your experiences).

This post has been edited by Weird Music Mafia: Nov 20 2005, 14:34
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Porcus
post Oct 19 2008, 10:21
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Since this thread is resurrected already, I might even quote a three-year old posting:

QUOTE (Weird Music Mafia @ Nov 18 2005, 12:55) *
Attention: It's often said that only recordings mastered before 1986 use pre-emphasis --> definitely wrong !!!
Some labels do use it just up to date (but not regularily) e.g. Erato and the Swedish label BIS (on almost every second CD) !!!

In short (I can only tell about classical, though) - which labels are suspicious to use it more frequently than others?


When it comes to classical music, some budget labels are just buying the rights to an old recording, and the release might just be a copy of the old master with the same pre-emphasis flag. This Bach box from 2001 consists of 160 CDs, of which I think 18 had pre-emphasis. The recordings are probably old, I might look it up if anyone cares. The box has later been repackaged and released as this 155 CD set in 2006 -- I have no idea if there is still pre-emphasis. (I would indeed not be surprised if somewhere there is a CD around, which is a reissue of a pre-emph'd CD but without the flag, i.e. wrong-sounding.)


Apart from that, I know that Swedish darkwave label Cold Meat Industry was quite eager to release pre-emph'd CDs in the nineties. I have a few of their releases.

This post has been edited by Porcus: Oct 19 2008, 10:26


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Porcus
post May 29 2012, 17:45
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Edit: was searching up some pre-emphasis discussion, and later realized that the topic title is off mark. Oh well, sorry for that ...



Emphasis [sic!] mine:

QUOTE (Porcus @ Oct 19 2008, 11:21) *
QUOTE (Weird Music Mafia @ Nov 18 2005, 12:55) *
Attention: It's often said that only recordings mastered before 1986 use pre-emphasis --> definitely wrong !!!
Some labels do use it just up to date (but not regularily) e.g. Erato and the Swedish label BIS (on almost every second CD) !!!


When it comes to classical music, some budget labels are just buying the rights to an old recording, and the release might just be a copy of the old master with the same pre-emphasis flag. This Bach box from 2001 consists of 160 CDs, of which I think 18 had pre-emphasis. The recordings are probably old, I might look it up if anyone cares.


Turns out that the organ section of that box, was Hans Fagius' recordings (83 to 89) on ... BIS! In addition, the two other pre-emph'ed CDs in that box, seem to be BIS recordings too (based on track lengths).

So this label also sells recordings, and in doing so, spreads the disease.


(Culprits:
http://bis.se/people_info.php?pID=1623 and
http://bis.se/index.php?op=album&aID=BIS-CD-587-88
19 CDs total, not 18 as stated above.)

This post has been edited by Porcus: May 29 2012, 17:57


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Posts in this topic
- TheFodge   EAC changes the EQ [moderation: only via pre-/de-emphasis]   Oct 28 2005, 04:05
- - Tahnru   Ouch. If you would please, would you go into EAC...   Oct 28 2005, 04:09
|- - TheFodge   QUOTE (Tahnru @ Oct 27 2005, 11:09 PM)Ouch. ...   Oct 28 2005, 04:28
- - boojum   You might ant to submit samples and proof. ...   Oct 28 2005, 04:54
|- - TheFodge   QUOTE (boojum @ Oct 27 2005, 11:54 PM)You mig...   Oct 28 2005, 12:45
- - Societal Eclipse   Screenshots?   Oct 28 2005, 06:15
- - ShowsOn   Is it possible that you are listening to CDs using...   Oct 28 2005, 13:00
|- - TheFodge   QUOTE (ShowsOn @ Oct 28 2005, 08:00 AM)Is it ...   Oct 28 2005, 15:49
- - Cyaneyes   QUOTE (TheFodge @ Oct 27 2005, 11:05 PM)great...   Oct 28 2005, 15:06
- - Cyaneyes   I'm almost certain the issue is pre-emphasis. ...   Oct 28 2005, 16:04
|- - TheFodge   QUOTE (Cyaneyes @ Oct 28 2005, 11:04 AM)I...   Oct 28 2005, 17:00
- - Axon   If preemphasis is there, shouldn't it be atten...   Oct 28 2005, 16:11
|- - Cyaneyes   QUOTE (Axon @ Oct 28 2005, 11:11 AM)If preemp...   Oct 28 2005, 16:18
- - JeanLuc   QUOTE (TheFodge @ Oct 28 2005, 03:05 AM)I...   Oct 28 2005, 17:58
|- - TheFodge   QUOTE (JeanLuc @ Oct 28 2005, 06:58 PM)If I w...   Oct 28 2005, 19:20
- - Drenholm   Screenshots and short samples of the different ext...   Oct 28 2005, 18:18
- - KikeG   I wouldn't be so sure about EAC (and most ripp...   Oct 28 2005, 18:44
- - Cyaneyes   Wow.. very interesting to me that iTunes would kno...   Oct 29 2005, 03:38
|- - Pio2001   I had completely forgotten that I posted this ...   Oct 29 2005, 23:26
||- - TheFodge   QUOTE (Pio2001 @ Oct 29 2005, 06:26 PM)I had ...   Oct 30 2005, 02:10
|- - TheFodge   QUOTE (Cyaneyes @ Oct 28 2005, 10:38 PM)Wow.....   Oct 30 2005, 03:15
- - dreamliner77   IIRC, the fhg encoder allows for encoding of files...   Oct 30 2005, 02:21
- - rutra80   Now it would be nice to have a free tool that can ...   Oct 30 2005, 05:01
|- - TheFodge   QUOTE (rutra80 @ Oct 30 2005, 12:01 AM)Now it...   Oct 31 2005, 19:38
|- - ChiGung   QUOTE (TheFodge @ Oct 31 2005, 06:38 PM)QUOTE...   Oct 31 2005, 20:21
|- - smz   But... does anybody knows if this emphasis (rarely...   Nov 1 2005, 04:49
|- - fredhammersmith   QUOTE (ChiGung @ Oct 31 2005, 15:21) QUOT...   Mar 25 2008, 19:13
|- - Sound of Perseverance   QUOTE (fredhammersmith @ Mar 25 2008, 13...   Apr 21 2008, 16:08
|- - Glenn Gundlach   QUOTE (Sound of Perseverance @ Apr 21 2008, 0...   May 4 2008, 05:31
|- - dmdevotee   so, what is the best way for de-emphasis process?   Aug 24 2008, 17:39
|- - Glenn Gundlach   QUOTE (dmdevotee @ Aug 24 2008, 08:39) so...   Aug 24 2008, 18:30
- - Donunus   What version of EAC are you using? Wonder if this ...   Oct 30 2005, 09:25
|- - TheFodge   QUOTE (Donunus @ Oct 30 2005, 04:25 AM)What v...   Oct 30 2005, 14:17
- - dreamliner77   Has anyone tried asking Andre about de-emphasis ap...   Oct 30 2005, 16:09
- - Pio2001   Is the emphasis in MP3 exactly the same thing as i...   Oct 30 2005, 23:56
- - dreamliner77   I always assumed so.   Oct 31 2005, 00:49
- - ReD-BaRoN   Is it easy to tell if a CD has pre-emphasis or not...   Nov 1 2005, 05:43
|- - smz   QUOTE (ReD-BaRoN @ Nov 1 2005, 05:43 AM)...   Nov 1 2005, 13:57
- - rutra80   QUOTE (smz @ Nov 1 2005, 05:49 AM)But... does...   Nov 1 2005, 17:46
|- - Pio2001   QUOTE (smz @ Nov 1 2005, 05:49 AM)But... does...   Nov 3 2005, 00:24
- - Alex B   I have previously used correction values from a 15...   Nov 3 2005, 02:24
|- - smz   An interesting test (that I cannot do as I don...   Nov 3 2005, 03:38
|- - Alex B   QUOTE (smz @ Nov 3 2005, 05:38 AM)An interest...   Nov 3 2005, 16:34
|- - smz   WOW! it is totally different and a lot "s...   Nov 3 2005, 16:45
|- - markanini   QUOTE (smz @ Nov 3 2005, 05:45 PM)WOW! it...   Nov 3 2005, 16:53
- - Alex B   The file I used was recorded at -20 db. I didn...   Nov 3 2005, 17:06
- - Bill02888   As I'm re-ripping my entire collection I came ...   Nov 6 2005, 13:24
|- - Pio2001   QUOTE (Bill02888 @ Nov 6 2005, 02:24 PM)...   Nov 7 2005, 13:15
||- - dreamliner77   QUOTE (Pio2001 @ Nov 7 2005, 08:15 AM)QUOTE (...   Nov 8 2005, 02:32
|- - Alex B   QUOTE (Bill02888 @ Nov 6 2005, 02:24 PM)Unfor...   Nov 7 2005, 13:39
- - Deep_Elem   After reading this thread I went and tried sox.exe...   Nov 6 2005, 17:50
- - Bill02888   QUOTE If you have the old version of EAC with the ...   Nov 7 2005, 16:01
- - Weird Music Mafia   Hi, guys! I'm collecting classical CDs si...   Nov 18 2005, 11:55
|- - Porcus   Since this thread is resurrected already, I might ...   Oct 19 2008, 10:21
|- - Porcus   Edit: was searching up some pre-emphasis discussio...   May 29 2012, 17:45
- - SebastianG   Out of curiosity: Is there any place on the web sh...   Nov 18 2005, 14:32
|- - fredhammersmith   Wow! Resurrecting a very old thread, but I...   Mar 22 2008, 04:57
|- - patmcg   QUOTE (fredhammersmith @ Mar 21 2008, 17...   Mar 22 2008, 09:15
|- - fredhammersmith   total commander rules!   Mar 22 2008, 17:31
- - hödyr   I don't know about the search function of XP c...   Mar 22 2008, 07:23
- - francesco   QUOTE (Pio2001 @ Oct 29 2005, 16:26) I ha...   Oct 2 2008, 17:40
|- - greynol   There is no option in EAC. The information will a...   Oct 2 2008, 18:39
- - francesco   QUOTE (greynol @ Oct 2 2008, 11:39) There...   Oct 2 2008, 19:22


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