Pre-emphasized CDs

[Porcus]

Re: Pre-emphasized CDs

I only have 2 or 3 pre-emphasized CDs. I doubt if anybody is going to have more than a handful them, so it's really not too bad.

I have quite a few (out of a total of 6000, I have to add). The most significant entries:

- The first Castle pressings of the old Black Sabbath albums.

- Some classical labels are using that thing still -- I guess that's because they are simply licensing an old recording. I have a box with Bach complete, and more or less the entire organ works part is pre-emph'd.

- Swedish darkwave label Cold Meat Industry -- here dBpoweramp reports partial matches.

[Rollo]

Re: Pre-emphasized CDs

The authors of Audacity have written a filter.

http://forum.audacityteam.org/viewtopic.php?f=13&t=9141

[EdBrady]

Re: Pre-emphasized CDs

I've used sox for this purpose... works very well, though not as convenient as having the capability built into dMC. I only have 2 or 3 pre-emphasized CDs. I doubt if anybody is going to have more than a handful them, so it's really not too bad.

[jh901]

Re: Pre-emphasized CDs

bump- anyone?

[jh901]

Re: Pre-emphasized CDs

has there been any movement on this issue?

these early Japanese CDs (several with 35DP- and CP35- catalog prefixes) are historically important, collectible, and in some cases have remarkable sound quality. is there a way to rip these into flac at this point? and, of course, with the properly adjusted eq for playback in, say, a Squeezebox system in the same way they would be heard on a CD player with the correct capability.

thanks!

Pre-emp is not supported, the discs are very rare as far as I can tell.

[Porcus]

Re: Pre-emphasized CDs

sox is GPL'ed and includes a de-emphasis filter. You don't even need to redistribute it if your "DSP" is merely a command line invoking sox, with a "please download and install sox version xxx" error message if it does not find it.

And, I'd still want a Vorbis comment saying PRE-EMPH: [Yes/Corrected/No]


sox: http://sourceforge.net/project/showf...group_id=10706

[Spoon]

Re: Pre-emphasized CDs

That has been around 5 years, has no source code, no visible license and no way of controlling externally, so no.

[jagged_fish]

Re: Pre-emphasized CDs

Does this constitute an opportunity?

http://www.picosound.de/E_soft.htm#emphasis

[Spoon]

Re: Pre-emphasized CDs

Only if opportunity presents its self.

[jagged_fish]

Re: Pre-emphasized CDs

Track Technical is reporting that all of the tracks on the Japanese band Casiopea's 'Mint Jams' CD have pre-emphasis. None of their later discs seem to have it, so this might well be the only CD in my collection which is affected.

Are there any plans to implement a de-emphasis DSP?

[Spoon]

Re: Pre-emphasized CDs

Pre-emph details never make it from the cd ripper to audio format.

--

Tommyz: sorry I did not see your post above, which language do you work in? c++

[Porcus]

Re: Pre-emphasized CDs

On what (lossless) file formats is a pre-emphasis tag/comment frequent enough to be interpreted during playback?

[tommyz]

Re: Pre-emphasized CDs

This is a 101 coeff FIR filter that emulates the needed deemphasis.
Note that it is NOT symmetrical, as it also emulated the phase (although only to about 10 degrees). But the amplitude is within 0.1 dB up to 20 kHz
Where do I find info on implementing DirectX or VST plugins ?

101
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[tommyz]

Re: Pre-emphasized CDs

De-Emphasizing is (normally) done using a passive network with a 50/15 us time constant.

This would have to bew implemented a IIR filter, as I have read elswhere a first order filter would get closer than 0.1 dB.

But I would have to look for the coeffs first...


ciao, TommyZ

[Spoon]

Re: Pre-emphasized CDs

The DSP effects are non-trivial to implement, how easy is pre-emp to implement?