remove pre-emphasis from cd's

[bvollrath]

Hey, I have a couple of cd's that have the pre-emphasis on them. The high frequencies are boosted. When I play them through my upsampling d/a converter at home, the highs are not reduced. So I want to remove the pre-emphais and make the copies like regular cd's. I am wondering if there is any software that can remove the pre-emphasis? Or is there a filter or plugin that I can use? I do have Sound Forge 7. Any help is appreciated.

Brian

 

[rebootjim]

SoundForge, Lowpass filter.

 

[scarecrow]

Personally I use EAC to rip such CD's to wav, and then edit them via Steinberg Wavelab and the Waves Parametric Equalizer. The results are absolutely the best you can achieve, the only problem is the price of Wavelab and the Waves VST plugin...
Of course the whole thing can also be done for free, with just a small quality handicap: EAC for Ripping, Winamp 2.9X (5.X should also do the job) with the file writer plugin (to output to .wav instead of your speakers) and Naoki Shibata's Shibatch equalizer plugin.
Of course there might be other FREE ways too, eg Audacity sound editor and some free VST plugin (or just the embedded program filters).

 

[bvollrath]

I have thought about using the eq in sound forge, but I don't know the exact settings to use. I have searched the internet, but I can't find it. Does anyone the exact eq settings that I should use? Is there a specification for emphasis?

Brian

 

[LTR12101B]

http://www.escape.de/users/colossus/faq.html#undopreemph

CDDA2WAV (part of the CDRECORD tools) has the capability to undo pre-emphasis - the -T option
http://www.fokus.gmd.de/research/cc/glone/employees/joerg.schilling/private/man/cdda2wav-2.0.html

Unix tools, CYGWIN port for Win32


Found one reference, not a full technical detail though:
With control bit number four, "pre-emphasis (on/off) is indicated. The player reads this bit and automatically switches to the appropriate de- emphasis circuit." . The standard de-emphasis for a CD (when used) has a flat response (0 dB) from 20 Hz up to about 3 kHz and then rolls off to about -10 dB at 20 kHz. "By attenuating high frequencies without affecting overall signal frequency response, the signal-to-noise ration of the signal may be improved." [8]

The definitive answer:
http://www.picosound.de/E_soft.htm#emphasis
Looks like GOLDWAVE has a 100% solution.

If I read it right, it's a rolloff of 6db/octave, 3dB at 3183Hz (the 50uS time constant), countered by a 6dB/octave boost from 10610Hz.

I thought it might be possible in the NYQUIST plugin language of Audacity, but while the lowpass is easy, there is no simple high boost.

Another NYQUIST option that may work, is the shelving....

(eq-highshelf signal hz gain [slope])
A fixed-parameter, second-order treble shelving equalization (EQ) filter based on snd-biquad. The hz parameter (a FLONUM)is the halfway point in the transition, and gain (a FLONUM) is the treble boost (or cut) in dB. The optional slope (a FLONUM) is 1.0 by default, and response becomes peaky at values greater than 1.0.

- From the illustrated curve, particularly the asymptotic, it looks like...
Treble gain (cut) is -10dB
Midpoint is about 5.6KHz
Slope is 1.0 (non-peaky)

 

[bvollrath]

Thanks, LTR12101B that info is definately helpful. Now I'll just wait for that guy at picosound to get that filter done and I'll be all set.

Brian

 

[LTR12101B]

Looks like his filter is in Goldwave - but it might be worth trying re-ripping the CD in CDDA2WAV with the -T option - the tail end of that is my thoughts on using Nyquist - in http://audacity.sourceforge.net/ - I've never been too hot on those strange languages though, they make about as much sense to me as RPN.

 

[bvollrath]

waves q10

I want to let everyone know that I also found out that Waves Q10 does have a setting for CD pre-emphasis. You can check out their website here http://www.waves.com/htmls/prods/indi/q10.html#
Thanks for all of the help,
Brian

 

[Duracell]

I want to let everyone know that I also found out that Waves Q10 does have a setting for CD pre-emphasis.

thanks for reporting, always useful to know;

Greetings from
Duracell

 

[nhatkhoi]

... every question about ... wave ...will be easy to come true! please contact me if ...

Please share your wisdom here, open for all so everyone may profit. Just go sure you respect the developer's and publisher's copyrights.
thread edited by me;

Duracell