Re: M2V - RealTek
- From: "RobF" <rfox24x@xxxxxxxx>
- Date: Fri, 31 Oct 2008 10:25:12 -0500
"Paul" <nospam@xxxxxxxxxx> wrote in message
news:gedbrc$dp1$1@xxxxxxxxxxxxxxxxxxxxxxxxxxxx
| RobF wrote:
| > From: "Paul" <nospam@xxxxxxxxxx>
| > Subject: Re: M2V - RealTek sound problem
| > Date: Wednesday, October 29, 2008 2:06 PM
| >
| > RobF wrote:
| >> After trying to copy sound from a DVD to HD, sound became very
| >> distorted,
| >> loud static, poor quality. This had also happened some time ago,
before
| >> misusing Audacity as copier. I fixed that earlier prob by removing
| >> cordless
| >> optical mouse. How to fix damage I may have caused by not knowing how
to
| >> use
| >> Audacity, being in a hurry, etc? In the previous instance of sound
| >> corruption, updating drivers, uninstalling/reinstalling, whatnot, did
not
| >> effect cure. Suggestions appreciated.
| >
| > Can you describe in more detail, what you're doing ? Is this some
| > kind of analog recording (wiring something to Line-In or Microphone-in
| > on the motherboard) ? Are you using a digital technique (ripping) ?
| >
| > When recording analog audio, you want to make sure the input level is
| > not exceeding the max for the input. Otherwise, there would be
| > clipping. Looking at the waveform in Audacity, should be
| > giving some hint as to what is wrong with it.
| >
| > For example, I used two programs to do some tests on the
| > audio on my computer. I used Audacity to play a test tone
| > through LineOut. (Audacity has a menu item to make a sine
| > wave test tone.) I connected LineOut to LineIn, thinking
| > the levels on them would be compatible. But in fact, the
| > output volume can only be set to 90%, in order to avoid
| > clipping on the recordings on LineIn. I used Windows Recorder
| > or the like, to record what was being played by Audacity.
| > (I could not find a way to both play and record in Audacity
| > at the same time.)
| >
| > The purpose of doing that experiment, was to provide some
| > proof the audio was working properly. But to understand
| > what test cases make sense in your case, you'd need to
| > provide a better description of your technique, wiring,
| > or tools.
| >
| > Paul
| >
| > Thanks for your response, Paul. I'm far out of my depth in using
Audacity. I
| > thought it would be a straight forward simple proceedure to snatch, rip,
| > copy a piece from a DVD that I own so that I could include it in a group
of
| > miscellaneous songs that I'd sometime like to burn to a CD-R. Whatever
it
| > was that I did resulted in the audio chaos I described.
| > I have 4 speakers and a sub woofer. Running the test tone in Audacity, I
get
| > clear tone good volume in front speakers, very weak volume in rear ones.
| > Running a .wav file in Audacity gives good tone front, none back.
| > In Windows Media player, a file from hard disk gives bad sound from
rear.
| > Terminology in sound engineering is beyond me. I think that whatever
| > "clipping" is, that is not what is occurring.
| > What basically I'm trying to do now is simply to restore sound quality,
rear
| > speakers. I can be only puzzled about what happened, not analytical. If
you
| > have further thought, I'd appreciate receiving them.
|
| It took me a while, but I found a test sound file :-)
|
| Try this page.
|
| http://www.halfgaar.net/surround-sound-in-linux
|
| At the bottom, is a channel-id test file. It is a WAV
| file, apparently marked as being six channels.
|
| http://www.halfgaar.net/media/chan-id.zip
|
| Unzip it first, to get chan-id.wav (3,469,916 bytes).
|
| Open that in Audacity, and you should see six waveforms.
| Click the usual play thing, and the human voice samples
| should test each speaker. (My copy of Audacity, says it
| will downsample to two channels, if I try to save the file,
| so saving any work you do in there, looks like it would
| be a problem.)
|
| Using that file, you can highlight the active section of each channel,
| and choose Generate:Tone, then modify the frequency from
| 440Hz to some other frequency. The tone should be a sine wave.
| That would cause a sine wave to be played through each channel
|
| Now, one problem is, your rear audio connectors only have
| three jacks. That means there is no way to use a 1/8" male
| stereo to 1/8" male stereo cable, to record the output
| of each channel as you test. So at the moment, I don't know
| of a way to quantify your distortion or noise problem.
|
| Otherwise, what you'd do, is something like this. This would be
| an option on perhaps a motherboard with five audio jacks on
| the rear panel.
|
| Front pair x--- male to male stereo cable ------x Line-In
| Rear pair
| Center/LFE
|
| You'd run the Microsoft Sound Recorder application, and accept input
| from Line-In. In Audacity, you'd play the six channel waveform.
| The Line-In would only record what is coming from the Front
| speakers. You'd repeat the experiment by moving the cable so
| you could record the Rear pair, and then the Center/LFE, using
| two more test runs.
|
| Then, you'd open the recorded stereo wave files, and try to put the
| recorded waveform, next to the originating waveform. That
| would allow you to compare the signals and note any
| differences.
|
| You could probably do math on the waveforms (subtract one from
| another), and see what kind of differences exist. But for the moment,
| doing the above somehow, is enough of a challenge.
|
| Anyway, at least try playing the test file, and check
| for distortion with your ear.
|
| Paul
Thanks very much for your good info and detailed help. Much appreciated. I'm
going to work on your suggestions now. With all you've provided, I won't
have to post further.
--
RobF
Address anti-spammed
.
- References:
- M2V - RealTek
- From: RobF
- Re: M2V - RealTek
- From: Paul
- M2V - RealTek
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