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Thread: Pre-emphasized CDs

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  1. #1

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    Aug 2007
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    Pre-emphasized CDs

    I think dBpoweramp is the best CD ripper and conversion utility out there. The reference edition with the multi-CPU support is a great time saver when ripping large libraries of CD's. Thanks for the excellent program.

    One question - Some CD's have the upper frequency range emphasized. CD players typically will recognize this and during the DA process de-emphasize so the response on playback is flat. The information on whether the track is emphasized is on the CD and transports detect this and act accordingly.

    With audio moving more and more to computer based and to alternative encoding formats ( I use FLAC) this information is lost and these CD's sound shrill when played.

    As far as I can see dBpoweramp does not recognize this nor have the option to perform de-emphasis when ripping and transcoding.

    Is there a way around this?

    Are there plans to include such capability in the program. This would be a big draw for the digital audiophile community.

  2. #2
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    Re: Pre-emphasized CDs

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

  3. #3
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    Re: Pre-emphasized CDs

    In "The Compact Disc Handbook" (Ken C. Pohlmann; A-R Editions Inc.ISBN 0-89579-300-8) the author gives a very clear explanation of how emphasis is applied, and the frequencies affected. The indicator signal to "tell" the CD player whether or not to apply de-emphasis is contained in the Q Channel.
    I agree with Spoon that emphasis is pretty rare in recent CDs, but may occurin older ones. The important point (to me, anyway) is that the CD player applies de-emphasis if it is required, in response to the Q Channel signal, so it should certainly not affect audio ripped from a disc. Question? Do CD-DVD ROMs and 'burners' respond to the Q Channel signal - that would be the crux of the matter. Tony

  4. #4

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    Re: Pre-emphasized CDs

    This could be done using a DSP effect.

    Is there an API for 3rd party developers?

  5. #5
    dBpoweramp Guru LtData's Avatar
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    Re: Pre-emphasized CDs

    No, but you can utilize DirectX or VST plugins as a DSP effect in dMC.

  6. #6
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    Re: Pre-emphasized CDs

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

  7. #7
    jh901's Avatar
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    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!



    Quote Originally Posted by Spoon View Post
    Pre-emp is not supported, the discs are very rare as far as I can tell.

  8. #8
    jh901's Avatar
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    Re: Pre-emphasized CDs

    bump- anyone?

  9. #9

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    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.

  10. #10

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    Re: Pre-emphasized CDs

    The authors of Audacity have written a filter.
    http://forum.audacityteam.org/viewtopic.php?f=13&t=9141

  11. #11
    dBpoweramp Guru
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    Re: Pre-emphasized CDs

    Quote Originally Posted by EdBrady View Post
    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.

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