How to Convert Mono sound to Stereo Sound?

Discussion in 'Amateur Video Production' started by cheamc, Jun 1, 2004.

  1. cheamc

    cheamc Guest

    I ve a video file that record in mono sound.(the viewcam have only mono
    output). I one to convert the sound to stereo. is that a way to do it in PC?
    I try it on Adobe premier but canot. Or they is another way?

    cheamc, Jun 1, 2004
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  2. Assuming you realize that you can't REALLY convert mono to
    stereo. If you have any questions about this, ask over in one of
    the audio newsgroups, i.e.
    If you mean how do I take something recorded on one channel
    and duplicate it to the other channel, that is a matter of using the
    appropriate adapters, mixers, etc when dubbing (or duplicating
    the channel during editing in Premiere, etc. "Audio Options,
    Duplicate Left or Duplicate Right", etc.))

    If you really mean how do I take a mono track and create "pseudo-
    stereo" there are some audio editing applications that have this
    feature, but it is universally "cheesy" at best, and often dreadful.
    Richard Crowley, Jun 1, 2004
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  3. cheamc

    Brian Guest

    Most video editors let you pan the sound. This is like a balance
    control where you can make the sound appear at a certain location
    between two speakers. You could locate a certain sound such as a voice
    on the left speaker then locate another voice or sound on the right
    speaker using the pan or balance audio control.
    This would work if one person is speaking at a time. When the person
    on the left speaks when you would pan the sound to the left speaker
    and pan to the right when the person on the right is speaking. This
    can be applied to sounds as well.

    You could also try adding stereo background music to make the video
    appear to be in stereo.

    Some sound processing programs have a simulated stereo feature for
    creating a stereo effect from mono sound.

    Regards Brian
    Brian, Jun 1, 2004
  4. cheamc

    dylan_j Guest

    Actually there are a number of ways to make mono sound into stereo
    sound but Premiere is usless. Download Audacity for free and use that.
    You'll have to export the sound from the original clip and then
    re-import it and sync it later to it's original clip (or syncing can
    be done in Quicktime Pro or something like that).

    The easiest way is to duplicate the mono sound onto a second track
    (making sure the're in perfect sync) and "invert" the second track,
    then pan each to hard gleft and right. this will give you a faux
    stereo spread, but if you try to listen to the sound in mono it will
    disappear. This is bad.

    Secondly you could duplicate the sound onto a second track and again
    pan each hard left and hard right, and then apply reverb to one track,
    which would give the impression of a direct sound from one speaker
    reverberating in the second, though this might not be the effect you
    want. Some reverb effects will automatrically create a stereo effect
    from mono, by creating different echo patterns in the left and right
    speaker. Alternatively you could apply a stereo chorus effect.

    The Best Way is more complex. Duplicate the soundtrack twice (so that
    you have three identical soundtracks. Pan one track hard left, one
    track hard right and one dead centre. Shift the centre track by a few
    milliseconds then invert either the left or right channel.

    If you had a Mac, I'd recommend you download Sound Hack - that can do
    all sorts of spooky things with stereo. I don't know the alternative
    to that in the PC world.

    dylan_j, Jun 1, 2004
  5. cheamc

    Jay Rose CAS Guest

    Or go to, scroll down to Sept '01, and download the free
    tunable mono>pseudo stereo preset, mono compatible, for SFX Machine. SFX
    Machine is a $25 - $99 Mac/Win audio app that any sound designer should

    Or download Stereoizer (moderately tunable Windows applet, but no
    previews) from the same source.
    Jay Rose CAS, Jun 2, 2004
  6. cheamc

    cheamc Guest

    Wow, they are so many way to do it. Anyway, thanks for your support and
    idea. I have follow one of the richard suggest using priemiere. Since i have
    the priemiere pro I would like to try it. And I have success to duplicate
    the left channel to the right channel. First by hightlight the footage and
    choose Audio option>breakout mono channel. Than three separete file will
    appear with one video and two audio left and right.
    I drag the original video footage to the timeline and unlink the video and
    audio. Cut out the audio and drag the left channel audio to the timeline
    with will place at audio 4. (the left channel ve sound). Encode it became
    one file and get the stereo sound.
    cheamc, Jun 2, 2004

  7. If you use any of the tricksy techniques described in this thread you
    will, although they can be superficially impressive, soon REALLY wish
    you hadn't :)
    Laurence Payne, Jun 3, 2004
  8. cheamc

    Larry Bud Guest

    Among other suggestion, one can put a small delay between the
    left/right channel. We're talking milliseconds. The larger the
    delay, the larger the separation sounds, until the delay is so large
    that your brain can actually tell that the two are delayed. Try
    around 100ms or so.
    Larry Bud, Jun 3, 2004
  9. My experience is that steps of 1ms give a position effect (left right),
    more then 3 or so ms give echo - spatial, more then 10 you can't tell
    what is happening, but start to hear echo.
    On music 10 ms is already pretty annoying.
    100 ms and you lose lipsync to.
    Jan Panteltje, Jun 3, 2004
  10. cheamc

    Jay Rose CAS Guest

    1/10th second - which is what 100 ms is - is on the threshold of where
    people will hear it as two sounds.

    Putting a somewhat smaller delay will just pull the sound to the other
    channel (precedence effect).

    Either case, you'd be really messed up if somebody's listening in mono...
    which is what most of the VHS setups in this country are (stereo VHS decks
    usually have mono RF outs).

    Use the phase technique described earlier, and implemented on the free
    software I pointed to: signal to both channels, signal delayed ~10 ms and
    added to right, same delayed subtracted from left. This makes
    complementary comb filters, which broadens the sound while keeping it
    centered, and the effect completely disappears for mono listeners.
    Jay Rose CAS, Jun 4, 2004
  11. cheamc

    Larry Bud Guest

    Could be. I don't do sound editing often, so I may be off by a factor of a few :)
    Larry Bud, Jun 4, 2004
  12. cheamc

    RandB Guest

    Why make it sound like voodoo?

    You've got a single-channel signal and you want it panned to the center of a
    stereo mix so that you're getting level on both L & R? Just pan the damn
    thing to the center. There's nothing "cheesy" or mysterious about it.

    RandB, Jun 4, 2004
  13. I know this, because I am matching up sound channels (mainly speech),
    with translation, that also have original sound (so I can have 5 languages
    in 5.1 ac3 on DVD). You put then one channel on the PA and the others on headphones
    with translations.
    The original sound in each channel must be in phase, my software combine_wave
    at allows you to do this
    in Linux from the command line, without any GUI in a few seconds.
    It has a finest resolution of 1mS... Perhaps I will make 0.1mS in a next version,
    but 0.1mS in this case is only 48000 / 10000 say steps of 5 samples...
    Audio is a very sensitive thing really.
    And I am not even an audio freak!
    Jan Panteltje, Jun 4, 2004
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