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

Mon Sep 9 16:11:20 EDT 2013

I just skimmed this sorry if I'm way off. 

Laptops usually have hopeless audio input.    Even if they have line-in,
it may be affected by noise on the system board. 

Griffin makes an iMic USB dongle which can provide excellent audio
input, either of MIC level or Line Level, and is not affected by all the
strange things going on inside the laptop.  

Also note that if you are coming from consumer grade audio, like a
cassette player, its headset output may distort at full volume.
Sometimes better to stick with 80% or less, and trim in incoming signal
to top-o-the-green. 

And unfortunately, digital inputs do not like to get clipped. 

On Mon, 2013-09-09 at 14:28 -0400, Ron Frazier (ALE) wrote:

> Hi Boris,
> 
> Thanks for the note.  I think this laptop just has the mic in, but I'll keep it in mind in case I run into machines with different configurations.
> 
> Sincerely,
> 
> Ron
> 
> 
> 
> Boris Borisov <bugyatl at gmail.com> wrote:
> 
> >You need boost for some type of microphones that are not very sensitive
> >or
> >if you speak far from the microphone. For record from any analog device
> >you
> >should use LINE IN -> LINE OUT
> >connection with proper cable. LINE levels are well known and are
> >standard
> >(0db or little more than 0.7 volts). Most laptops/netbooks have just
> >one
> >input jack normally MIC but this input is switchable trough mixer
> >control
> >panel between MIC/LINE. Make sure you are using LINE.
> >
> >
> >
> >On Mon, Sep 9, 2013 at 11:17 AM, Ron Frazier (ALE) <
> >atllinuxenthinfo at techstarship.com> wrote:
> >
> >> Hi all,
> >>
> >> Thanks for the replies to this message.  I know it's been a few days
> >but I
> >> wanted to follow up.
> >>
> >> Sometimes reality has a way of breaking through any delusions you
> >have
> >> about what's going on.
> >>
> >> The clipping turned out to be my fault, unknowingly, and it wasn't
> >the cd
> >> player.
> >>
> >> The audio controls for the mic input on this laptop have two sliders
> >you
> >> can move.  One is input level.  And the other is mic boost. 
> >Originally, I
> >> had the input level at about 70% and the mic boost at 10 db.  At that
> >> point, I was getting good clean waveforms.  Later, I decided I would
> >like
> >> it better if the level control was closer to 50%, so I put it there
> >and
> >> raised the mic boost control to 20 db.  In that configuration, the
> >waveform
> >> is clipped, even though the total level coming into audacity is
> >within
> >> bounds.
> >>
> >> I don't know why less boost and more level is OK and more boost and
> >less
> >> level fails.  I don't know what's going on in the hardware.  I only
> >found
> >> this out after I burned another cd from cassette input, which had
> >worked
> >> before, and it sounded all muddy and fuzzy.
> >>
> >> So, if you're recording in audacity or a similar program, and you get
> >a
> >> wave like the bottom one in my picture, you probably have something
> >wrong.
> >>
> >> I had to learn several other things too, like how to fix minimal
> >clipping
> >> in the source wave, how to boost up weak wave forms ripped from cd,
> >how to
> >> reduce down really loud ones from different sources (as I was making
> >a
> >> mashup), even how to somewhat remove a dc offset that infected one
> >cassette
> >> I had.
> >>
> >> Oh, and, if you're creating a cd from an audio book or something,
> >DON'T
> >> even think about just recording one hour long track on a cd.  This
> >will
> >> drive the person playing the disc crazy, if they want to go to a
> >certain
> >> section in the disc and have to hold the fast forward or backward
> >buttons
> >> down for 6 minutes to get 45 minutes into the program.
> >>
> >> Learned that the hard way too.
> >>
> >> In audacity, zoom into the waveform enough so you can see pauses
> >between
> >> words or songs.  Add a label at that point.  Then, when you're
> >through
> >> editing, you can select the entire thing and select export multiple.
> >>  Select to break on labels in the dialog box, set to auto number, and
> >> you'll get a number of little track files you can burn to cd.  You
> >may wish
> >> to export the full audio for editing later as well.
> >>
> >> Also, when I burned the cd, there was an option in the settings that
> >I had
> >> to check which said burn without gaps.
> >>
> >> For music, I made sure the waveform already had the gaps I wanted, 1
> >sec
> >> before and after each song.  For spoken word audio book, I just let
> >it run.
> >>  Having the burning software insert 5 sec gaps in the middle where I
> >didn't
> >> want them, the first time, was very frustrating.
> >>
> >> I did not try the function that's supposed to automatically break the
> >> tracks on silences, but did the breaking myself.
> >>
> >> I chose to put 1 hour of stuff on each cd and put track breaks every
> >6
> >> minutes.
> >>
> >> With the help of some stereo equipment that I bartered from Jim
> >Kinney, I
> >> was able to eventually create the music disc for my family's event
> >and it
> >> worked out very well.
> >>
> >> So, thanks to Jim and thanks to you guys for help with the audio.
> >>
> >> Sincerely,
> >>
> >> Ron
> >>
> >>
> >>
> >> Phil Turmel <philip at turmel.org> wrote:
> >>
> >> >Hi Ron,
> >> >
> >> >On 08/29/2013 01:14 AM, Ron Frazier (ALE) wrote:
> >> >
> >> >[trim /]
> >> >
> >> >> Look at this file.
> >> >>
> >> >>
> >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.
> >> >
> >> >From what is visible in that screenshot, it is almost certainly the
> >CD
> >> >player's output circuit clipping at that output volume level.
> >> >
> >> >Turn the CD player's output volume down until you see no clipping,
> >then
> >> >turn your capture card's input volume up (if necessary) to achieve
> >> >maximum sensitivity for that level.
> >> >
> >> >Clipping can occur in any amplifier circuit between the D/A
> >conversion
> >> >(in the player) and the A/D conversion (in your input card).  If the
> >> >clipping is happening in the player's first analog stages after the
> >D/A
> >> >conversion, before it gets to the volume control, you won't be able
> >to
> >> >fix it.  Your only option would re-level the master WAV to within
> >the
> >> >CD
> >> >player's capabilities.  (I'd toss the CD player if that's true.)
> >> >
> >> >Phil
> >> >
> >> >_______________________________________________
> >> >Ale mailing list
> >> >Ale at ale.org
> >> >http://mail.ale.org/mailman/listinfo/ale
> >> >See JOBS, ANNOUNCE and SCHOOLS lists at
> >> >http://mail.ale.org/mailman/listinfo
> >>
> >>
> >> --
> >>
> >> Sent from my Android Acer A500 tablet with bluetooth keyboard and K-9
> >Mail.
> >> Please excuse my potential brevity if I'm typing on the touch screen.
> >>
> >> (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
> >> mailing lists and such.  I don't always see new email messages very
> >> quickly.)
> >>
> >> Ron Frazier
> >> 770-205-9422 (O)   Leave a message.
> >> linuxdude AT techstarship.com
> >> Litecoin: LZzAJu9rZEWzALxDhAHnWLRvybVAVgwTh3
> >> Bitcoin: 15s3aLVsxm8EuQvT8gUDw3RWqvuY9hPGUU
> >>
> >>
> >> _______________________________________________
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> >> http://mail.ale.org/mailman/listinfo/ale
> >> See JOBS, ANNOUNCE and SCHOOLS lists at
> >> http://mail.ale.org/mailman/listinfo
> >>
> >
> >
> >------------------------------------------------------------------------
> >
> >_______________________________________________
> >Ale mailing list
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> >http://mail.ale.org/mailman/listinfo/ale
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> >http://mail.ale.org/mailman/listinfo
> 
> 
> --
> 
> Sent from my Android Acer A500 tablet with bluetooth keyboard and K-9 Mail.
> Please excuse my potential brevity if I'm typing on the touch screen.
> 
> (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
> mailing lists and such.  I don't always see new email messages very quickly.)
> 
> Ron Frazier
> 770-205-9422 (O)   Leave a message.
> linuxdude AT techstarship.com
> Litecoin: LZzAJu9rZEWzALxDhAHnWLRvybVAVgwTh3
> Bitcoin: 15s3aLVsxm8EuQvT8gUDw3RWqvuY9hPGUU
> 
> 
> _______________________________________________
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