[ale] [OT] Help! burned cd playback wave clipped, original wave perfect

[Boris Borisov]

CD headphone jack -> audio card could be tricky sometimes with levels,
impedance and whatnot. A lot of modern "Windows" drivers are having some
form of software layer that "enhances" sound, gives echo/ reverb effects,
software EQ and so on. I normally turn these off or if I can uninstall it.
I don't know what you recording setup is I'm guessing here.


On Thu, Aug 29, 2013 at 1:14 AM, Ron Frazier (ALE) <
atllinuxenthinfo at techstarship.com> wrote:

> Hi all,
>
> I need some help with an audio cd production I'm working on for a private
> family event.  This is a little complex.
>
> I've been working hard to pull some quality master audio waveform files
> from cassettes that I own.  The audio is as good as can be expected from a
> cassette tape, and is very decent to listen to.  I've worked hard to edit
> the files, set the levels, eliminate the clipping, and silence the space
> between songs.
>
> I saved the MASTER files as signed 24 bit pcm wav files, which are
> lossless.  I then burn the wav files to cd (standard cd audio) using
> Windows Media Player.  Bear with me, this is NOT Windows centric.
>
> Next I rip the cd I burned back to lossless wav files.  I then import the
> two waves, my master, and the ripped wave into audacity.  The waves look
> identical, as they should.
>
> So, I know that my master wav file and the wave file on the cd, ripped
> back into wav are exactly the same.
>
> Then I play the cd on a cd player and record back into audacity.  I make
> sure the volume on the input is NOT too high.  However, the waveform coming
> out of the cd headphone jack is visually severely distorted and clipped.
>
> Look at this file.
>
> https://dl.dropboxusercontent.**com/u/9879631/cd_playback_**clipping.png<https://dl.dropboxusercontent.com/u/9879631/cd_playback_clipping.png>
>
> The top waveform, titled ripped, is the file that was ripped from the cd.
>  It looks very nice and there is no clipping or excursions beyond the +/- 1
> amplitude levels.  It's just like the master file.
>
> The bottom file, titled played, is what was obtained by playing that same
> file (track) back and rerecording it.  Note that it is severely clipped,
> BUT, its excursions are nowhere near the +/- 1 limits.  This proves I don't
> have the input volume too loud.  This is something that's happening in the
> playback circuit of the cd player.  I've confirmed the behavior on 2 cd
> players and observed the same thing on a commercially recorded cd.
>
> Also, I've compared the audio playing back the ripped file, versus the
> played file from the cd player.  The ripped version sounds better and
> fuller.
>
> I wonder if they're doing some dynamic range compression on the output of
> the dac.  Whatever it is, it's not stored in the raw cd data.
>
> Does anyone know what this is and if there is a way to eliminate this, so
> that the true waveform on the cd, which is the same as my master, is what
> comes out of the speakers.
>
> Any help is appreciated.
>
> Sincerely,
>
> Ron
>
>
> --
>
> (PS - If you email me and don't get a quick response, you might want to
> call on the phone.  I get about 300 emails per day from alternate energy
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> quickly.)
>
> Ron Frazier
> 770-205-9422 (O)   Leave a message.
> linuxdude AT techstarship.com
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