Pre-emphasis

[Scarpia]

I never knew about this until today, when the "pre-emphasis" flag came up "yes" when I tried to copy a Harmonia Mundi CD to my hard disc in EAC.  Apparently pre-emphasis is an idiotic scheme where high frequencies are boosted before being encoded on a CD, then your CD player is supposed to reduce them again on playback.  The trouble is that programs like Exact Audio Copy will dutifully write the pre-emphasized data to your hard disc, then playback software such as foobar will ignore this pre-emphasis and play back your music with the inappropriate high-frequency emphasis.  Some claim that iTunes is able to compensate for pre-emphasis when doing rips. 

Has anyone else encountered this problem, and how do you deal with it?

[False_Dmitry]

Sounds dreadful.  Another nail in the coffin for recorded music.  Another reason to listen to live performances

[Scarpia]

If you use EAC it will indicate whether pre-emphasis is employed.  CD players are supposed to routinely correct for this.  I have no way of knowing if mine actually does.

Out of four discs I have read today, two had pre-emphasis.  Two discs of Bach Orchestral Suits by Harnoncourt did not (original Teldec releases), a Harmonia Mundi of Trio Sonatas and a cpo release wiht Casella Serenata Op 46, etc, did.

With the Harmonia mundi, I ripped it with EAC the result sounded too bright when played back on foobar.  When I ripped it with iTunes it sounded normal on foobar, so iTunes aparently understands and corrects for pre-emphasis.  EAC doesn't.

However, I don't like this solution.  With EAC I can rip in my prefered format - single sound file with a cue sheet.  iTunes gives a bunch of little files, which I don't want.

Anyone know how I can solve this?

[Scarpia]

There is a discussion thread here on this issue.

I followed up the guy's assertion that about half of all current BIS issues have pre-emphasis, by testing a selection of 10 recently-purchased CDs, and was amazed to discover he is right: 5 had no pre-emphasis, 4 had pre-emphasis on all tracks, and 1 (Schnittke Cello works) had pre-emphasis on the last 5 tracks but not the first 4.  Obviously this is more of an issue than I thought.

That thread is consistent with the information I have read.  If you use anything other than iTunes to rip a cd, the file you get will contain pre-emphasized data.  You might want that if you plan to copy the data to another cd, but the the most popular computer playback applications  (i.e., foobar) don't recognize this and play the file back without emphasis correction.  On the other hand, if you do use iTunes your ripped files will not be bit-identical with the originals.  So you can't burn an identical cd from them, but you can burn a cd that has no pre-emphasis.  To confuse matters, there is no way to verify that your CD player is taking pre-emphasis into account.

And it is not limited to old CDs, many CDs being released have it, like cpo discs. 

[sTisTi]

I've also had trouble with pre-emphasis in the past: after discovering that some of the CDs I ripped sounded strange on computer playback I identified pre-emphasis as the culprit and had to go through my 1000+ CD collection to find all CDs affected by this problem 

My results were as follows:
- Universal (Philips, DG, Decca): not a single CD with pre-emphasis
- Chandos: the same
- Sony/CBS: the same
- EMI: the same
- Erato (also re-issued ones by Warner): some CDs had pre-emphasis, but rare
- Hyperion: A lot of 1980s/early 90s releases were affected, but none of the more recent releases
- BIS: same like Hyperion
- Harmonia Mundi: Only one late 80s CD affected, otherwise pre-emphasis-free
- Arte Nova: Some CDs affected (even a 2005 release)

It really seems to have been a vogue among some labels in the 80s/early 90s to use pre-emphasis, but with the exception of Arte Nova it's very rare for CDs released, say, after 1995.

The easiest and most reliable way to get rid of pre-emphasis really is iTunes, I'm afraid. At least I couldn't find any other option that seemed reliable when I searched (The quality of the Wav file editor solutions seem to be contested). iTunes recognizes the pre-emphasis flag and corrects the frequencies accordingly, so you get a WAV file that sounds as it should. The "loss of stereo separation" issue sounds like nonsense to me, pre-emphasis has nothing to do with stereo, it's basically just an equalizer curve that is applied to attenuate the frequency bands that are encoded too loud on the CD in order to get a "correct" frequency curve again.

By the way, this is only a problem when ripping CDs for listening on the computer. All stand-alone CD players correct the pre-emphasis automatically (it's part of the CD specifications), so no need to worry in this regard.

[Scarpia]

The easiest and most reliable way to get rid of pre-emphasis really is iTunes, I'm afraid. At least I couldn't find any other option that seemed reliable when I searched (The quality of the Wav file editor solutions seem to be contested). iTunes recognizes the pre-emphasis flag and corrects the frequencies accordingly, so you get a WAV file that sounds as it should. The "loss of stereo separation" issue sounds like nonsense to me, pre-emphasis has nothing to do with stereo, it's basically just an equalizer curve that is applied to attenuate the frequency bands that are encoded too loud on the CD in order to get a "correct" frequency curve again.

I'm sold on iTunes.  The only problem is that I wanted to standardize on a format consisting of single flac file with cue sheet.  iTunes gives me a cluster of wav files that I can convert to flacs if I want.  But is there an easy way to convert that set of wav files to a single wav (or flac) file with cue sheet?  I haven't found one.

I am tempted to chuck out the idiotic freeware and just use iTunes and Apple lossless for everything.

[sTisTi]

I'm sold on iTunes.  The only problem is that I wanted to standardize on a format consisting of single flac file with cue sheet.  iTunes gives me a cluster of wav files that I can convert to flacs if I want.  But is there an easy way to convert that set of wav files to a single wav (or flac) file with cue sheet?  I haven't found one.

I am tempted to chuck out the idiotic freeware and just use iTunes and Apple lossless for everything.

I don't use cue sheets myself, but I know there are a bunch of cue sheet tools available that let you split cue sheets into separate files (and probably vice versa). Have you tried e.g. CUE Tools 1.9.1 (freeware) ?
See here: http://wiki.hydrogenaudio.org/index.php?title=CueTools

[kishnevi]

- Arte Nova: Some CDs affected (even a 2005 release)

A lot of Arte Nova is re-releases.  Could the pre-emphasis be an artifact carried over from the original mastering?

[petrarch]

I'm sold on iTunes.  The only problem is that I wanted to standardize on a format consisting of single flac file with cue sheet.  iTunes gives me a cluster of wav files that I can convert to flacs if I want.  But is there an easy way to convert that set of wav files to a single wav (or flac) file with cue sheet?  I haven't found one.

I am tempted to chuck out the idiotic freeware and just use iTunes and Apple lossless for everything.

It sounds like you use a Mac, therefore I can heartily recommend http://sbooth.org/Max/, which can rip to single or multiple flac files with or without cue sheet.

[Daverz]

It sounds like you use a Mac, therefore I can heartily recommend http://sbooth.org/Max/, which can rip to single or multiple flac files with or without cue sheet.

Max does not detect pre-emphasis correctly, let alone apply de-emphasis.  I filed a bug on this months ago, but it seems that Max has been end-of-lifed anyway.  Sbooth's successor, still in beta, is called Rip, and it's what I use on my Macs now.  Still does not apply de-emphasis.  For that I use sox.

[Daverz]

had to go through my 1000+ CD collection to find all CDs affected by this problem 
My results were as follows:

Add Supraphon to the list.  Most Supraphon discs before 1994 used pre-emphasis.  Also Unicorn and some early Vox issues.

- Sony/CBS: the same

Some CBS discs have pre-emphasis: Gould's 1981 Goldbergs and some of Walter's Mozart Symphonies for example.

It really seems to have been a vogue among some labels in the 80s/early 90s to use pre-emphasis, but with the exception of Arte Nova it's very rare for CDs released, say, after 1995.

But reissues often just reproduce the original masters, so recent Brilliant Classics reissues of Bis and Unicorn CDs have pre-emphasis, and this is true of some of Bis's own reissues.

By the way, this is only a problem when ripping CDs for listening on the computer. All stand-alone CD players correct the pre-emphasis automatically (it's part of the CD specifications), so no need to worry in this regard.

Sorry, many CD players, particularly recent makes, do not apply de-emphasis.  The Cambridge Audio 840C, for example.  I don't now how they get away with not supporting this part of Red Book.

One of the Stereophile test CDs has some pre-emphasized test tones that can be used to test CD players.  A program like Audacity could then be used to check that the tones were properly de-emphasized.

[Daverz]

I never knew about this until today, when the "pre-emphasis" flag came up "yes" when I tried to copy a Harmonia Mundi CD to my hard disc in EAC.  Apparently pre-emphasis is an idiotic scheme

Pre-emphasis was not idiotic, it was a way of squeezing a few extra bits of performance out of CDs at a time when DACs weren't very good.  It creates a lot of inconvenience for rippers and for those with CD players that don't support the full Red Book spec, but that's not something that could have been forseen by those who came up with the idea.   Correctly de-emphasized CDs can sound excellent.

then playback software such as foobar will ignore this pre-emphasis and play back your music with the inappropriate high-frequency emphasis. 

Without something like a cuefile, there's no way to detect that pre-emphasis was applied to the audio in a wav file.   That's a fault with the wav format.

Has anyone else encountered this problem, and how do you deal with it?

Here's a simple script that applies de-emphasis to a directory of flac files using sox.  If you don't want to remove the original flacs, delete the "&& rm "$flc"" part, and if you don't want the de-emphasized files to be 24 bit, remove the "-b 24" part.

#!/bin/sh

for flc in *.flac 
do 
  echo "Applying deemphasis to '$flc'."
  sox "$flc" -b 24 "${flc%.flac}_deemph.flac" deemph && rm "$flc"
done

[Daverz]

There is a discussion thread here on this issue.

I followed up the guy's assertion that about half of all current BIS issues have pre-emphasis, by testing a selection of 10 recently-purchased CDs, and was amazed to discover he is right: 5 had no pre-emphasis, 4 had pre-emphasis on all tracks, and 1 (Schnittke Cello works) had pre-emphasis on the last 5 tracks but not the first 4.  Obviously this is more of an issue than I thought.

Judging by the discs in my own collection, Bis stopped using pre-emphasis somewhere between catalog number 600 and 700.  That does not include reissues.  The anniversary issue of Tubin's Symponies 3+8, for example.

[DavidRoss]

Aha!  This may explain why the BIS recording of Panula conducting orchestral songs by Sibelius, BIS 270, sounds crappy, whereas the BIS recordings with Vänskä sound fine.  And if some CD players apply de-emphasis but some don't, why some GMGers think discs like BIS 270 sound fine but others don't.

Could it be that most, if not all, disagreements among relatively rational folks likewise stem from incomplete data regarding relevant experience and relative emphasis?

[Daverz]

Aha!  This may explain why the BIS recording of Panula conducting orchestral songs by Sibelius, BIS 270, sounds crappy, whereas the BIS recordings with Vänskä sound fine.  And if some CD players apply de-emphasis but some don't, why some GMGers think discs like BIS 270 sound fine but others don't.

Could it be that most, if not all, disagreements among relatively rational folks likewise stem from incomplete data regarding relevant experience and relative emphasis?

I'd estimate about 3 to 4% of the discs in my collection of about 3500 CDs use pre-emphasis.  So it might explain some disagreement, but not most disagreement.

Also, Bis did make some just plain bad recordings, pre-emphasized or not.

[DavidRoss]

I'd estimate about 3 to 4% of the discs in my collection of about 3500 CDs use pre-emphasis.  So it might explain some disagreement, but not most disagreement.

Now where did Rob put that "subtle ironic wit" emoticon?

[Daverz]

That is consistent with my findings.  The highest catalog number I found with pre-emphasis is 580 (counting 300507 as 507).  And not everything below that has pre-emphasis either, e.g. Tubin's Symphonies 4 & 9 (#227).

Yup, not everything before that used pre-emphasis.  I've been keeping a box of pre-emphasized CDs.  Just checked it; the latest Bis in there is CD-690, Lepo Sumera, Musica Tenera; Piano Concerto; Symphony No. 4, with a publish date of 1994. 

Supraphon stopped using pre-emphasis about the same time.  When they re-reissued the same recordings after that, they redid the mastering without pre-emphasis as far as I can tell from the examples in my collection.

[Daverz]

Now where did Rob put that "subtle ironic wit" emoticon?

Subtle ironic wit aside, there's a grain of truth there.  I put up an Amazon review of a CD complaining of its harsh sound before I discovered that it was recorded with pre-emphasis and my CD player was to blame.  I'm sure this has happened to other people. 

(BTW, I'm pleased to find out that all our past disagreements were simply because I was unable to detect your subtle ironic wit.)

[DavidRoss]

Subtle ironic wit aside, there's a grain of truth there.  I put up an Amazon review of a CD complaining of its harsh sound before I discovered that it was recorded with pre-emphasis and my CD player was to blame.  I'm sure this has happened to other people. 

(BTW, I'm pleased to find out that all our past disagreements were simply because I was unable to detect your subtle ironic wit.)

It wasn't mine, but yours I was commenting on.

Not just a grain of truth but a bushel.  And CDs were not the subject of the expanded comment about disagreements among rational folk...but then you already knew that, didn't you? 

And speaking of subtle ironic wit reminds me how much I still miss Nigel around here.  Sigh....

Hmmm...come to think of it, I'm not sure that we've ever disagreed, just failed to see things from the same point of view.  It's amazing how many seeming disagreements are really misunderstandings stemming from the failure of one or both parties to see things from the other's perspective. 

[Scarpia]

Sorry, many CD players, particularly recent makes, do not apply de-emphasis.  The Cambridge Audio 840C, for example.  I don't now how they get away with not supporting this part of Red Book.

One of the Stereophile test CDs has some pre-emphasized test tones that can be used to test CD players.  A program like Audacity could then be used to check that the tones were properly de-emphasized.

The other question is whether pre-emphasis is properly sent and understood when using a digital link to a separate DAC.  From what I understand SPDIF has a status bit that tells whether the data should be interpreted as having pre-emphasis, but who knows whether the player has properly asserted the bit or whether the DAC is interpreting the bit.  The Cambridge Audio DACMagic, which I have been considering, has an array of status lights but non for pre-emphasis.  If, as you say, Cambridge Audio CD players ignore pre-emphasis, it seems likely their DAC does as well.

The digital de-emphasis strikes me as problematic.  If the input signal uses 100% of the quantization range, then the de-emphasized signal will certainly exceed 100% at times.  This would cause clipping, unless the volume of the track is reduced. 

In any case, to test if your cd player understands pre-emphasis this should work (you will need iTunes and EAC (exact audio copy) software:

1)  Find a pre-emphasized disc.  (If you put a pre-emphasized disc into your PC with EAC running, you will see "yes" indicated for pre-emphasis.)

2)  Copy a track from the disc to a wav file on your hard disk using iTunes.  iTunes recognizes pre-emphasis and makes a wav file which has been corrected.  Copy the same track using EAC, which will do no correction. 

3) Use an audio player like foobar to listen to the two tracks using your computer (ideally with headphones).  Your audio player has no way of knowing if a wav file uses pre-emphasis or not and that will give you an indication of the difference de-emphasis makes.

4)  Burn the wav file you made with iTunes to a CD.

5)  Compare the original CD with the iTunes processed wav file.  The iTunes file should sound normal because the de-emphasis has been incorporated into the wav data itself.  If the original CD sounds similar to the iTunes processed file, your CD player is doing de-emphasis.  If the original CD sounds a lot brighter, then your CD player is playing the original CD without de-emphasis.   You may hear a subtle difference between the tracks even if de-emphasis is working because of subtle differences in the de-emphasis methods.