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  4. Velocity X-Fade Switch Issue?

  • Velocity X-Fade Switch Issue?

    J
    J
    Hey guys,

    I have some important polyphony issue wen the "Velocity X-Fade" switch is on.

    I'll give you an example.

    Let's say I load the patch "Strings_sus_Vib" into a VI instance. I write the following notes :

    <a href=http://www.jeromeleroy.com/files/vi-velocity_xf.jpg">

    Now, logically, the 11 notes should play one after the other, and around bar 3 I should hear the low A by itself.

    When the VELOCITY X-FADE switch is *off*, everything works fine.

    When the VELOCITY X-FADE switch is *on*, whatever the velocity level chosen in the GUI, the low A will stop right when the 11th note comes in.

    When the VELOCITY X-FADE switch is *on* and the PLAY RELEASE switch is on too, then as soon as the 7th note plays, the A will stop playing.

    So, this is definitely some kind of polyphony issue with the VELOCITY X-FADE switch. It happens whatever the velocity level : as soon as the VELOCITY X-FADE switch is on, the number of voices seems to drop like crazy.

    I do not understand why this switch would make such a difference, especially since the Velocity level in itself doesn't matter (the problem happens at both high or low velocities)

    This is not a processor or a ram issue - VI is the only thing loaded in memory, with only one patch in the matrix (on a Powermac Quad with 4.5GB of Ram)

    Did you see that before? What do you think the problem is? Is that a bug or what?

    Thanks,
    Jerome

    --------
    Powermac Quad, 4.5GB of Ram, OS X 4.7
  • H
    H
    One instance of a VI is limited to 64 voices.
    If you are using Xfade velocity with a patch of four or more velocity layers,
    the VI is using for a single note 4 voices.
    If Release samples are active one notes requires 8 voices.
    So you would run out of polyphonie playing a chord with more than 9 notes.

    So if you want to use Xfade and release samples with this kind of cluster you have to split the notes to two different VI instances.

    best
    Herb
  • J
    J
    Thanks Herb for this explanation.

    What I don't understand is why the Velocity X-Fade is using 4 voices for a single note. What is the difference between Velocity X-Fade and changing the velocity manually in the sequencer?

    As in my example, if I write notes with the highest velocity (= 127) and play them back with the VELOCITY X-FADE switch turned *off*, it sounds the same as if I write the notes with *any velocity* and play them back with the VELOCITY X-FADE switch turned *on* at the maximum level.

    So why does it use 4 times more voices if it just sounds the same? I'm sure there's a logical explanation, but it doesn't make sense to me at this point...

    Jerome
  • H
    H
    When velocity XFade is active, all four velocity layers are running if you hit any key, otherwise it would be impossible to blend between the velocities.
    The VI have to be prepared that you Xfade between the velocities at any moment you like. So if you don't Xfade this is not relevant, fact is, that you could do it, and than it has to work.

    best
    Herb
  • J
    J
    Thanks Herb, that totally makes sense now [:)]

    In some ways though, you would most probably use Velocity X-Fade than Expression to control dynamics? It seems expression merely control some sorte of volume.

    Jerome
  • P
    P
    If you split the track to two identical VI instances, can you then use LEARN on both at the same time? Or does that cause memory problems?