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

Mon Sep 9 14:28:21 EDT 2013

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
>> >
>> >_______________________________________________
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>>
>>
>> --
>>
>> 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
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>>
>>
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>
>
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--

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