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  1. Hi guys.. me and my friend had an argument the other day...
    Few of the songs I own are mono. I said that whenever I try to convert a mono source to stereo, it's nothing but joint stereo (both left and right channels are the *same*). But he says that one can convert any mono source to pure stereo. I replied saying that it's impossible... In pure stereo, it's obvious that both the channels differ. And, when my mono source has one channel, how does it hold the information regarding the other channel to make it a pure stereo??

    Am I wrong?? plz correct me

    P.S: my friend says that he has a stereo file and it appears like 5 *different* streams when he listens to that sound using his 5:1 subwoofer. he says that the same logic is applied to mono <-> pure stereo case and the sound card is responsible for it
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  2. Always Watching guns1inger's Avatar
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    Joint Stereo is in fact stereo, but where all the common audio data is stored only once, instead of in each channel. What you have is still mono, but in 2 channels.

    Can you convert mono to stereo ? Yes. For the restoration of the The Good, The Bad and The Ugly they took the original mono audio and created a 5.1 sound track. They did it by cutting it up and rebuilding it. You could apply a similar idea to create a stereo track from a mono source. Add to that some fancy phase shifting and you will get something that is not mono. Of course it is not always as successful as this. I also have a restoration of Carnival of Souls which boasts a restored 5.1 AC3 and DTS audio track. This is not so impressive.

    Dolby Pro-Logic II can take a stereo source and create a mock 5.1 output. It creates 6 discrete channels. If the source was a well mixed Dolby ProLogic audio track then the results can be as good as a true 5.1 mix.
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  3. Simulated Stereo is not considered stereo.

    Trying to make mono into stereo, stereo in surround, were tried as early as pre-digital elelctronics. Engineers use filters, delay lines,. mixers to channeled left, right, front, back out from the mono audio. Result was never convicing with most people that who have expereince with live muisc. Hardly any people care for it, then as well as now.
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  4. Member valvehead's Avatar
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    This is like colorizing a b&w film. It doesn't make it a color film. Even the best ones still look fake.

    Using delay, phase or frequency shifting to create "stereo" from mono can sound interesting, but it will never be true stereo. In fact very few pop music recordings these days are entirely true stereo. They are generally composed of mono sources panned in the stereo field. Only the drum overhead mics and possibly ambient mics are true stereo. The exception would be classical (and some jazz) recordings which are often recorded with a single pair of mics (though the use of spot mics is more common now).
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  5. Member Cornucopia's Avatar
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    Originally Posted by trolldown
    Hi guys.. me and my friend had an argument the other day...
    Few of the songs I own are mono. I said that whenever I try to convert a mono source to stereo, it's nothing but joint stereo (both left and right channels are the *same*). But he says that one can convert any mono source to pure stereo. I replied saying that it's impossible... In pure stereo, it's obvious that both the channels differ. And, when my mono source has one channel, how does it hold the information regarding the other channel to make it a pure stereo??

    Am I wrong?? plz correct me

    P.S: my friend says that he has a stereo file and it appears like 5 *different* streams when he listens to that sound using his 5:1 subwoofer. he says that the same logic is applied to mono <-> pure stereo case and the sound card is responsible for it
    So your answer is that it is NEARLY IMPOSSIBLE. It is possible to do, but the effort involved in doing it (right/convincingly) is about as much as making it up from scratch to begin with.

    You're quite right about stereo channels differing, etc. That's exactly why it's easier to go from stereo to 5.1, because you already have at least 2 separate things, to play off against each other as it were. Not true with true mono (or the same mono applied to 2 channels, aka DUAL MONO), where every signal is the same before you put that effort into it that I just talked about. Any "automatic" processing applied to mono in order to make it sound like stereo is CRAP and won't fool anybody with half a brain.
    Notice your friend said his stereo file appeared "like" 5 streams, not that he could swear that it WAS 5 different streams. That's what Dolby processing is SUPPOSED TO DO (whether correctly, from true matrixed multichannel sources, or accidentally from plain stereo sources).

    Scott
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  6. Going Mad TheFamilyMan's Avatar
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    Pure stereo? Interesting term. I like "true stereo": ideally stereo is where the original live sound stage is reconstructed in your living room. I've heard very few stereo recordings that manage to pull this off. When you've experienced it, it's truely amazing. Not only are spatial positions noticable, but also front/back placement as well. A very good hifi is also required, along with a good listen environment. Getting this from a mono recording to this may be possible with a great engineering/remastering effort, but it is not very likely.
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  7. Except a few real good direct to disc cut, or real live recording. There are rarely any good and real stereo material around. When you hear one, with good hi-fi, that will make the hair on the back of your neck stand up.

    Overly mixed and too many re-sampling of music, may help to cut cost on studio session cost, but that's what it is a mix!
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    Originally Posted by trolldown
    But he says that one can convert any mono source to pure stereo. I replied saying that it's impossible... In pure stereo, it's obvious that both the channels differ.
    Your friend is kinda correct (but just "kinda"). You can't get true stereo (or what you call pure stereo) because stereo is defined as originating from two separate inputs (microphones, etc), but you can get psuedo stereo, where the original sources are identical, but are manipulated so that in the end product, they differ from one another. You can prove this to yourself by taking a mono source and placing on both channels, then delaying one by 10mS. This is a real quick-and-dirty test, and you can immediately see a difference. Better experiments will use both delay and remixing - ie, delaying channel 1 by 20mS, then creating another pair of tracks by mixing (20% CH1 + 80% CH2 for one track, and 80% CH1 + 20% CH2). This will definitely give better results than the first experiement. Even better results can be achieved by trying to remove the voice audio from the background music, then applying the stereo effect to the music, then remixing back in the audio. The more elaborate you get, the more difficult the task becomes.

    So in the end, you CAN have a pretty good psuedo stereo effect - the delay gives separation and the mixing gives spacial effects. I usually try this on soundtracks that are totally mono.
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  9. BuskerAlley.com zoobie's Avatar
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    too true...I've had success with psuedo stereo from mono.

    but if you phaseshift then play the DVD thru a stereo tv, it can sound like a dropout.

    My fav is taking a full stereo signal, split, and simply shift it a tad...it can be quite amazingly sweet...leaving the audio as produced in the studio...

    the idea is to create your own stereo...
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  10. thanks for your input guys.. it's kind of making sense to me now
    As a layman(to studio mixing & audio technology), I've used the term 'pure stereo'. tx for correcting me here..

    so if I want to experience drums frm one speaker, guitar from another one,vocals from another one of a mono source, do I have to do those phase shift, delay adjustments?? or are today's generation sound cards capable of doing these adjustments automatically??
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    Adobe Audition has some presets for experimenting with this technique.
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  12. Going Mad TheFamilyMan's Avatar
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    In my experience, playing around with phase shifting does little more than make your material sound like it was recorded in a large drainage pipe. But maybe that's the desired effect....Good Luck!
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  13. Member edDV's Avatar
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    Originally Posted by trolldown

    ...

    P.S: my friend says that he has a stereo file and it appears like 5 *different* streams when he listens to that sound using his 5:1 subwoofer. he says that the same logic is applied to mono <-> pure stereo case and the sound card is responsible for it
    That means his sound system is faking extra tracks with a DSP. True stereo or 5.1 requires multiple mics and tracks at the start.
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