Can I trigger parameters of a MIDIOutput Event from nested STGCs?

Question

I'm making a sequencer in Kyma that outputs midi using the MIDIOutput Event.

Initially I'm starting with a 4 step sequence but I'm about to make it much more complex with nested loops.

If I put the expression that calculates the current note value in the MIDIOuput Event it works fine:

MIDIOutput Event:
    Frequency:
    (((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq1Value suffix: i]}) + 60) nn hz

But as I add more levels of nesting this expression is going to become unweildy and hard to debug because I can't see (in the VCS) any intermediate values. But if I create a STGC to create a !Gate signal and another STGC to calculate the current note value (!SeqVal) then weird notes start coming out over midi (half way between values).

Mixer:
    Inputs:

        SoundToGlobalController:
            GeneratedEvent:
                !Gate
            Value:
               1 bpm: !BPM

       SoundToGlobalController:
           GeneratedEvent:
               !SeqVal
           Value:
               ((((!Gate nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq1Value suffix: i]}) + 60) nn hz

       MIDIOutput Event:
           Frequency:
               !SeqVal
           Value:
               !Gate

 

I've tried delaying the !Gate signal in the MIDIOutput Event using turnOnAfter: for: and while that had some odd effect it didn't fix the problem. How do I create a sound that can work out the note value for the MIDIOutput Event without having to write the entire expression in its frequency parameter?

 

I've attached two example sounds - the first one that works where the entire expression is in the MIDIOutput Event and the other where I've tried to refactor that expression into STGCs unsuccessfully.

http://kyma.symbolicsound.com/qa/?qa=blob&qa_blobid=394791909300513371

Comments

Alan, have you tried doing both?  Couldn't you put the full expression for frequency and gate directly into the MIDIOutputEvent to ensure sample-accurate synchronization and also put intermediate expressions into STGCs so you can monitor each of the intermediate results visually?

---

I have tried putting the full expression in the frequency and gate fields. As I change the tempo the loops seem to get out of sync and the notes start going weird.

Here's the frequency expression:

(
    (
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level1Effect suffix: i]})
        *
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq1Value suffix: i]})
    )
    +
    (   
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level2Effect suffix: i]})
        *
        ((((1 bpm: (!BPM/4)) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq2Value suffix: i]})
    )
    +
    (
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level3Effect suffix: i]})
        *
        ((((1 bpm: (!BPM/16)) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq3Value suffix: i]})
    )        
    +
    (
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level4Effect suffix: i]})
        *
        ((((1 bpm: (!BPM/64)) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq4Value suffix: i]})
    )
    +
    60
) nn hz



and the gate expression:


1 bpm: !BPM dutyCycle: (
    (
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level1DutyEffect suffix: i]})
        *
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq1Duty suffix: i]})
    )
    +
    (   
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level2DutyEffect suffix: i]})
        *
        ((((1 bpm: (!BPM/4)) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq2Duty suffix: i]})
    )
    +
    (
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level3DutyEffect suffix: i]})
        *
        ((((1 bpm: (!BPM/16)) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq3Duty suffix: i]})
    )        
    +
    (
        ((((1 bpm: !BPM) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Level4DutyEffect suffix: i]})
        *
        ((((1 bpm: (!BPM/64)) nextIndex) mod: 4) of: {(1 to: 4) collect: [:i | !Seq4Duty suffix: i]})
    )
)



As you can see "1 bpm: !BPM" is repeated all over the place. I imagine it's all of those bpm: expressions that are going out of sync when I move the !BPM fader. How would I factor out the "1 bpm: !BPM" so it only occurs once?

Answer 1

Hi Alan,

You'll get a more accurate clock using the form:

1 bpm: !BPM triggerEvery: 64

in places where you have an expression of the form:

1 bpm: (!BPM/64)

Hope that helps!

Comments

why is this happening?

---

In one case (triggerEvery), you are sharing the same clock and triggering every 64th tick. In the other, you are creating a new clock by dividing a number by 64. Because all arithmetic you do on a computer has finite precision, this new clock rate may not be *exactly* 1/64th the rate of the original clock.