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[JONCAT]

From: http://www.head-fi.org/forums/f7/benchmark-dac1-now-available-usb-223006/index133.html#post3861337

"Some great information here. I have another question regarding pre-emphasis flags from older CDs. I use my computer for playback, and I noticed in the DAC1 literature that it applies de-emphasis if the marker was set. I have a set of Black Sabbath CDs from 1986 that have pre-emphasis, and I want to play them without having to use a program to correct the change in frequency. If they are .flac images with .cue sheets with the pre-emphasis flag set, and I play the .cue sheets from foobar, would the DAC1 know to apply de-emphasis? Thanks in advance for any help."

Any thoughts?

DC

[benn600]

I almost thought your question would be about what J River's pre-emphasis was with MC12 to see if they succeeded.  Now that you made me think of that I'm curious!  Of course I was there when they started it.  And I could look back...but I wonder what it's like from their perspective...  Dual purpose thread title?

[Alex B]

"Some great information here. I have another question regarding pre-emphasis flags from older CDs. I use my computer for playback, and I noticed in the DAC1 literature that it applies de-emphasis if the marker was set. I have a set of Black Sabbath CDs from 1986 that have pre-emphasis, and I want to play them without having to use a program to correct the change in frequency. If they are .flac images with .cue sheets with the pre-emphasis flag set, and I play the .cue sheets from foobar, would the DAC1 know to apply de-emphasis? Thanks in advance for any help."

Any thoughts?

DC

Where did you copy that from?

I don't' see how it could be possible on PC playback. The audio playback system does not have a mechanism for embedding that kind of information in the played PCM stream.

I guess that a standard for adding this info in the PCM stream exists. Otherwise the de-emphasis feature in DAC1 would be useless. I have assumed that stand-alone CD players with integrated DACs read this flag and switch the de-emphasis correction on using an external method outside the actual audio stream, but maybe this is incorrect.

I started a thread about pre-emphasis three years ago: http://yabb.jriver.com/interact/index.php?topic=26276.0.

Here is how I use EQdb for de-emphasis correction: http://yabb.jriver.com/interact/index.php?topic=40270.msg274867#msg274867


EDIT

Google found the source:
http://www.head-fi.org/forums/f7/benchmark-dac1-now-available-usb-223006/index133.html#post3861337

[JONCAT]

Thanks, I must have spelled it wrong in my search yesterday; there are a lot of hits here.

Searching for a list of albums w/ pre-emphasis I came across this discussion:

http://www.stevehoffman.tv/forums/archive/index.php/t-88541.html

Myself, I never encountered pre-emphasized CDs with wrong TOC (not flagging pre-emphasis).
....

I'd always opt for FFT de-emphasis, and ditch convolvers when archiving my records, to be on the safe side.

I couldn't believe this TOC problem, too. But I've checked it with all Plextors and Pioneers available - at home and at work. Plextools Professional as well as the current EAC detect the preemphasis only at my self-burnt CDs and Lionel Richie - Can't Slow Down.
But "Detect TOC manually" in EAC prebeta3 detects the preemphasis from the subchannels in all the CDs mentioned above - and one can easily hear that this is correct.
I did an out-of-phase-compare of the results of my foobar convolver and the FFT-Filter in Samplitude (which I used for the impulse resonse). The result was "nearly identical". I don't hear a difference.
But still, I don't think that FFT-Filtering is the best way for this purpose. Preemphasis and deemphasis-filters are originally analog - and not phase-linear. So, in a perfect world the deemphasis-filter reverts like a mirror all the phase-shifting done by the preeemphasis-filter. Which means it must be designed like an traditional analog filter.

DC

[JONCAT]

So could the flag be detected by MC & ripped accordingly to compensate?

http://www.digital-inn.de/exact-audio-copy-english/19034-pre-emphasis-use-eac.html

If you have one of those rare old CDs that are pre-emphasized you will want to de-emphasize the wav files before converting them to MP3s. The encoder in iTunes will automatically perform de-emphasis for such CDs. I have found two of my old CDs were preemphasized: Santana's Beyond Appearences and Pink Floyd's The Wall. One way to see if your CD is pre-emphasized is to open it with Exact Audio Copy (EAC) and look at the far right column.

..or use this tool instead of EQ/software compensation:

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 desribed in André's 3rd post above. 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 99% before using the tool...

I'm interested in testing some older discs that I have. A few posters claimed it is really rare & limited mostly to classical recordings, but others claim it's still used.

Alex - did you use EAC to detect Pre-emp is the first place?

Would MC apply Pre-Emp noted in a cue sheet as discussed here?

http://www.stevehoffman.tv/forums/archive/index.php/t-113248.html

I understand that if you use iTunes to rip the CD, it will automatically de-emphasize (which means that the track is digitally re-equalized). But it could be possible that iTunes does not recognize the pre-emphasis if it is not part of the TOC.

Programs like CloneCD will not take care of pre-emphasis flags; you will have to set them manually (if possible with your CD burning porgram).

The best way to make correct CDR copies of pre-emphasized CDs is to use EAC, produce a cue sheet, and if for some reason pre-emphasis is not recognized, add add the command "FLAGS PRE" for every track. As an example, here is the cue sheet of the black triangle Abbey Road CD that produces a correct CDR copy with pre-emphasis flags:

REM GENRE "Classic Rock"
REM DATE 1969
REM DISCID EE0B1C11
REM COMMENT "ExactAudioCopy v0.95b3"
PERFORMER "The Beatles"
TITLE "Abbey Road"
FILE "The Beatles - Abbey Road.wav" WAVE
TRACK 01 AUDIO
TITLE "Come Together"
PERFORMER "The Beatles"
FLAGS PRE
INDEX 01 00:00:00
TRACK 02 AUDIO
TITLE "Something"

DC