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Topic: Effect to make a sound gradually spread across the sound field?

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  1. #1

    Effect to make a sound gradually spread across the sound field?

    Is there an effect, or method, to let me make a sound seem to come from a given point, and then spread, gradually or not, across the sound field? In stereo, in other words, the sound might appear to originate from dead center and but then spread out ---not just pan, but spread out--towards the left and right, with the sound still coming from the center but also opening out around me as it decays.

    In surround, the sound would originate from perhaps dead center, and then spread around the side speakers and then to the back. Thinking of a piano sound,of course, where the strike would be localized, but the sutained note and decay and shimmer spread out around one, as it does, fast, while you sit at a piano. In an extreme form, the effect would be unrealistic, but I'm wondering what the sound would be if the spread from center to the sides was done in a few milliseconds--the harmonic shimmer after all comes from across the keyboard, and does spread around the player as the strings and wood all over the piano vibrate. (I'm aware a mic won't localize the sound of the string resonance, but at the same time, I'm curious about playing around some to see what happens if the decay of the fundamental and harmonics spread in this way.)

    The best thing I can think of so far is to create a surround stage with the source spread equally among all the speakers, but with the amplitude turned down for all but the front two speakers, with an automated increase in level to the side speakers and then the back speakers. But this is no fun to create. Any simpler way?

  2. #2
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    Re: Effect to make a sound gradually spread across the sound field?

    It sounds to me like a wet mix of stereo delay and/or chorus, accompanied by gradually spreading pan settings, would achieve the effect you're after.

  3. #3
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    Re: Effect to make a sound gradually spread across the sound field?

    Then again, that might come across as extreme and unrealistic unless very tiny amounts were applied.

  4. #4

    Re: Effect to make a sound gradually spread across the sound field?

    It would be interesting to put a mono instrument into Giga, then send it to GigaPulse in Multi-mode with the far left and far right seats selected. Then slowly adjust the width of the instrument from min to max.

    Hmm. That won't quite work. With a mono signal the sound would be the same. I'd probably need to do multiple tracks - one without processing, the other with GigaPulse, and simply crossfade them.

    I'll try out some options this weekend...

    -JF

  5. #5
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    Re: Effect to make a sound gradually spread across the sound field?

    Maybe this would work:

    3 tracks, the first panned to center and remaining at center.

    The second and third tracks pan left and right, respectively, at the speed you choose, using automation.

    I believe you would have to automate to increase the volume of the first track as the second and third moved left and right.

    I think this would, in principle, work in surround as well but I doubt it could happen as quickly as a few milleseconds. Does MIDI move that fast?

    Jim

  6. #6

    Re: Effect to make a sound gradually spread across the sound field?

    joeb: When I think of the term "stereo delay" I think of an effect that reproduces the sound--echoes it. Is there a standard effect that lets one control the rate spread of the spread across the stereo spectrum? (Not a pan from center to wide L\R, but instead "opening" up the sound so it spreads to include the sound at the wide L\R pan positions while not moving the sound entirely to those positions?


    JonFairhurst: I know so little about convolution that anything I would say would be unproductive, but maybe I do need to look more into a way to start a sound playing very briefly in mono and then spread to stereo. Maybe that's what I'm really after. Do you know if there's a vst that does this?

  7. #7

    Re: Effect to make a sound gradually spread across the sound field?

    This might work. Duplicate the sound twice in stereo, one set in phase and the other out. If you start wth the in-phase version and cross-fade to the other you should go from a very focused mono to a hole-in-the-center cancelled out sound that might be just the thing.

    Oh, just re-read the original post and you want to do it in surround... well, fun with phase cancellation still can give some cool "wide" effects even in multi-channel... try it out!!

  8. #8

    Re: Effect to make a sound gradually spread across the sound field?

    (I know more than one person on this forum is about to tell me to just break down and get a damned piano...)

    I don't know that midi can move that fast. But I'm thinking that it would have to occur in milliseconds so it could be closely controlled--in the same way that a millisecond or two can make a huge difference in the attack section of an amp envelope or latency, the speed at which the sound would spread might make a big difference in realism. Ideally, I guess, I would be able to control the rate of spread, come to think about it--I would want to be able to create an envelope that could define Attack (the rate at which the sound spread) and Sustain (the amplitude at which the outermost spread of sound sustained, or a ratio of the amplitude of the initial sound to that of the outermost sound) and Spread (how far out sound spread). Seems as though a VST with an algorthm to change the phases might be better, though I have no idea how to create such a thing.

    I don't necessarily need to do it in surround--the effect just may be more possible in surround. (The more I think about this, the more I see how little I understand stereo and the breadth of field--is there even a way to spread a sound out in a stereo channel, as opposed to just wide-panning--and without this slowly spreading effect, so a note occupies a wider area in space? In other words, so it's spread across several pan positions?)

    If so, what I may want (or may ALSO want) is a way to better localize harmonics. After all, on a piano, the harmonics come in part from sympathetic vibration of upper strings, and these and the bass octaves excited will send out waves to the right and left of the body more than the fundamental will, unless the fundamental is in the lower or upper octaves. (One problem with many older piano soundfonts seems to be that the sound of the upper harmonics on medium and upper velocity strikes seems to be localized at the same position as the fundamental--also a problem with any close micing technique, I imagine.)

    I think I need a review of just what stereo actually is. Either the result of two mics recording the same note from different positions or an illusion caused by phasing, yes? So I can try the method you suggest of adding new samples and then crossfading. Of course I'm thinking of doing for all the samples on each piano note...No fun, but I'll try the middle octave and see how it sounds. This is what I get for drinking too much coffee.

    Eh....How would I create the out of phase samples?

  9. #9

    Re: Effect to make a sound gradually spread across the sound field?

    Wow, no that's not going to work for sampling an entire piano. Plus, it changes the tone quite a bit.

    Stereo itself doesn't necesarly involve phase cancellation- that's just a way to use stereo to create a perception of something that's "more 3D", in a very subjective way of course. Stereo itself is mothing more than sound coming from two locations, which your two ears then process as being "wide". It's really that basic, but the applications thereof can fill large books of acoustics, and I'm no acoustic technician by any stretch!! There are those around who are that might be able to help you more...

  10. #10

    Re: Effect to make a sound gradually spread across the sound field?

    Fred--So you're thinking more in terms of playing back a recorded track? Why wouldn't the crossfading work sample by piano note sample? Just because of the speed of midi and the need to automate crossfading every note? (Just...)

    Obviously, this may all be a wild and unproductive idea. As I say, too much coffee. I do like the idea of doing it with convolusion, too, though

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