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Topic: CD de-emphasis? (Read 28785 times) previous topic - next topic
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CD de-emphasis?

Whenever I find old threads dealing with this topic they provide links to software that no longer exists.  I have a CD with pre-emphasis that is not removed on playback.  I want software that removes it so I can make a no emphasis CD.  What is there?

Ahead of time since a lot of people seam to get confused about this - pre-emphasis boosts the high frequencies.  It is up to the playback system to attenuate them.  Adding to the difficulty, most early Japanese CDs (my field of interest) do not implement the flag correctly so even if the playback system is perfect it won't recognize the pre-emphasis.

I saw someone had luck using iTunes instead of EAC for ripping.  Well, I tried it and it didn't work.
Daniel L Newhouse

CD de-emphasis?

Reply #1 –
I only own a single CD with pre-emphasis, so my experience is limited.

First I tried with sox. It basically worked, but the resulting file length didn't exactly match the length of the original file. I haven't tried if this is also the case with recent versions.

WaveEmph doesn't suffer from this problem. But when searching for the website, I found that apparently many people have trouble running the program.

CD de-emphasis?

Reply #2 –
Quote from: dnewhous on
I saw someone had luck using iTunes instead of EAC for ripping.  Well, I tried it and it didn't work.


Are you sure it didn't work? I find it funny since all CDs with pre-emphasis I have tried (ripped to AAC, though) sounded right. I can upload a sample from Dire Strait's "Alchemy" live CD if you want.

CD de-emphasis?

Reply #3 –
Quote from: Sebastian Mares on
Are you sure it didn't work? I find it funny since all CDs with pre-emphasis I have tried (ripped to AAC, though) sounded right. I can upload a sample from Dire Strait's "Alchemy" live CD if you want.


If you think I'm that stupid, why bother asking the question?  I already gave an answer and an explanation.
Daniel L Newhouse

CD de-emphasis?

Reply #4 –
Quote from: caligae on
...I tried with sox. It basically worked, but the resulting file length didn't exactly match the length of the original file.
Sox works great for me; used it many times.  I've never experienced a file length problem...

CD de-emphasis?

Reply #5 –
Quote from: esa372 on
Quote from: caligae on
...I tried with sox. It basically worked, but the resulting file length didn't exactly match the length of the original file.
Sox works great for me; used it many times.  I've never experienced a file length problem...


Just tried with a recent version and now the original and processed file are the same regarding file length. So either this was fixed or I did something wrong last time.

So sox is probably the best bet.

CD de-emphasis?

Reply #6 –
Is there a site anywhere that compiles a list of CDs with pre-emphasis?

CD de-emphasis?

Reply #7 –
Quote from: krabapple on
Is there a site anywhere that compiles a list of CDs with pre-emphasis?

Your ears should tell you.  There should be some sort of marker.  On early Japanese CDs it's the "TO" marker after the matrix number.
Daniel L Newhouse

CD de-emphasis?

Reply #8 –
sox worked, the other thing crashed.

Has anyone tried Waves Q10?  I just wonder if it does a better job.  There is some subtlety in designing the filter because the specification is for an analog filter.
Daniel L Newhouse

CD de-emphasis?

Reply #9 –
This has been brought up in other threads, but you can use iTunes to rip a CD with pre-emphasis on it, and iTunes will apply the correct de-emphasis curve when it saves the file to disc. I know people don't like using iTunes as a ripper, but it seems WAY easier doing it that way than messing with these other programs. I have heard that SOX screws up the file length (wrong number of samples), and also I read somewhere that it mis-aligns the stereo channels when doing the de-emphasis function.

There is a thread here on how iTunes seems to do it right.

[a href='index.php?act=findpost&pid=339177']http://www.hydrogenaudio.org/forums/index.php?showtopic=38312&st=25&p=339177&#entry339177[/a]

CD de-emphasis?

Reply #10 –
Quote from: dnewhous on
Whenever I find old threads dealing with this topic they provide links to software that no longer exists.  I have a CD with pre-emphasis that is not removed on playback.  I want software that removes it so I can make a no emphasis CD.  What is there?

Ahead of time since a lot of people seam to get confused about this - pre-emphasis boosts the high frequencies.  It is up to the playback system to attenuate them.  Adding to the difficulty, most early Japanese CDs (my field of interest) do not implement the flag correctly so even if the playback system is perfect it won't recognize the pre-emphasis.

I saw someone had luck using iTunes instead of EAC for ripping.  Well, I tried it and it didn't work.


You mention that "most early Japanese CDs" "do not implement the flag correctly."

If you are SURE that a CD has pre-emphasis applied to the audio tracks, and EAC shows the flag is not present, then you could rip the disc with EAC, and then manually edit the cue sheet (add FLAGS PRE to each track) and then burn a new one from EAC using the cue sheet.

That will generate a CD with the same audio data, but with the pre-emphasis flag set properly. At that point, it should play properly in a CD player, and also should be processed by iTunes with the de-emphasis curve applied to the resulting files.

CD de-emphasis?

Reply #11 –
I thought I read somewhere (don't remember where) that older versions of iTunes de-emphasized correctly but the newest version doesn't do it anymore.

CD de-emphasis?

Reply #12 –
Quote from: gordolindsay on
I thought I read somewhere (don't remember where) that older versions of iTunes de-emphasized correctly but the newest version doesn't do it anymore.


I just tried iTunes 8 with The Beatles Abbey Road - Toshiba EMI Black Triangle from 1983, and it seems to have worked for me.

I verified that the pre-emphasis flag was set on the disc by reading it with EAC. (There is a column for the pre-emphasis indicator for each track.)

Then I ripped the disc with iTunes to standard WAV files. I then compared the iTunes generated WAV files with the WAV files previously ripped by EAC, and the iTunes files have de-emphasis built in, the original EAC ripped files do not.

I did not compare them by using any software, just by listening on a computer, and the difference is quite noticeable. The EAC ripped originals are way to bright and harsh, and the iTunes de-emphasised files sound the way they should.

CD de-emphasis?

Reply #13 –
Is preemphasis flag on CDs set at the track level, or at the album level?  In other words, would it be possible to scan an archive of (losslessly) ripped tracks for presence of pre-emphasis, generating a list of tracks that have it?    If so, is there such a tool?  (Something analogous to the HDCD.exe tool, which detects hdcd encoding on a per-track basis.)

The only PE detection tool I'm currently aware of is EAC, which requires reading the CD.

CD de-emphasis?

Reply #15 –
Quote from: greynol on
Unlike HDCD information which is embedded in the audio data itself, pre-emphasis information is stored in the subcode.


So, subcode data is not 'ripped' along with audio data, by EAC?

CD de-emphasis?

Reply #17 –
Quote from: greynol on
It's detected, but such information will only be found in a cue sheet provided that you created one.


I rip CDs as separate tracks, so there are no cue sheets.  So, is there any way to objectively detect pre-emphasis on those? 

CD de-emphasis?

Reply #19 –
I think I've found a CD with incorrectly implemented pre-emphasis - the original CD release of Heaven 17's "The Luxury Gap" (http://www.discogs.com/Heaven-17-The-Luxury-Gap/release/321964 - says it was released in 1988 but I'm not sure how reliable that is, Virgin were releasing some CDs in 1983/4). High frequencies are uncomfortably loud when listening to it normally, but it sounds much more "normal" when I applied de-emphasis using SoX (doesn't seem to have any length or stereo issues as others experienced) - similar to the 2006 remaster except without unecessary compression/limiting and bass boosting.

The CD has the DCP flag on all but the first track - maybe they just set the flags arseways and meant to use the pre-emph flag?

One thing I've noticed with SoX's de-emphasis is that the output is very quiet - the album peak is 0.615814 now instead of 0.977264. I guess this is normal when de-emphasis is applied without normalization?

Edit: See http://sox.sourceforge.net/Docs/FAQ regarding SoX's now fixed stereo imaging bug

CD de-emphasis?

Reply #20 –
Quote from: Zilog Jones on
One thing I've noticed with SoX's de-emphasis is that the output is very quiet - the album peak is 0.615814 now instead of 0.977264. I guess this is normal when de-emphasis is applied without normalization?


Yes, this is what I noticed as well.

If I apply de-emphasis to an album with pre-emphasis, I get much reduced peak levels and RG.
If I apply de-emphasis to an album with no pre-emphasis, the peak level and RG values change just a bit (with 1dB) and the sound becomes more "murky".

I guess this can be a way to identify an album with pre-emphasis although I don't know if it's foolproof.

CD de-emphasis?

Reply #21 –
Quote from: Boiled Beans on
I guess this can be a way to identify an album with pre-emphasis although I don't know if it's foolproof.
It depends on the amount of energy in the (high) frequency range where the emphasis is active. I remember that with emphasis on, one had to reduce the recording level by several dB to avoid digital overloads. With classical music that contains little energy in the HF range this was much less of a problem than for popular music. This was the main reason that many recording engineers had their digital recorders modified to get rid of the emphasis.

I've never tried it but I suppose that if you can find a silent part of the audio with only noise, it might be possible to find out if emphasis was used because the noise will have a 10 dB lift towards 20 kHz. This probably won't be caused by dither and noise shaping since these were introduced after the emphasis period was mostly over. IIRC

CD de-emphasis?

Reply #22 –
Quote from: Boiled Beans on
If I apply de-emphasis to an album with pre-emphasis, I get much reduced peak levels and RG.
If I apply de-emphasis to an album with no pre-emphasis, the peak level and RG values change just a bit (with 1dB) and the sound becomes more "murky".

I guess this can be a way to identify an album with pre-emphasis although I don't know if it's foolproof.
::

Pre-emphasis can be reliably identified with CDDA2WAV. You can find it in the cdrtools package e.g. here:
Free Software
Example command line:
cdda2wav.exe" dev=SPTI:0,1,0 -info-only -no-infofile -no-fork -gui
... red depends on your drive's connection.

It's able to detect PRE-flag in TOC and/or subchannel (EAC is detecting TOC only!).

(sorry for my bad english)


Greetings ...

::

CD de-emphasis?

Reply #23 –
Thanks for this Surfi.  I thought I saw that EAC only read the TOC someplace else but couldn't remember.  Do you know if the TOC contains this information on a per-track basis (as indicated in the EAC GUI) or just for the entire disc?

Unfortunately in krabapple's situation it can't be used for tracks that have already been ripped.

CD de-emphasis?

Reply #24 –
Quote from: greynol on
Do you know if the TOC contains this information on a per-track basis (as indicated in the EAC GUI) or just for the entire disc?
::

Just for the entire disc, AFAIK. It would be nice if Andre could somehow use CDDA2WAV's functionality for EAC (like he does with CDRDAO).

::