Rms type or Cosine type Crossfade Curves

Jeetender

here is a small code, i have a wet and and dry module in HISE, using simple gain, and there is a knob on the UI names wetdryknob, now this script works fine switching between wet and dry from -100 to 0db, but at 50% both the gain are at -50db, the curve is linear, iam not goo at maths, but the gain output should be constant and gain matched. how can i achieve it.

const var wetdryknob = Content.getComponent("wetdryknob");
const var FX1 = Synth.getEffect("WET");
const var FX2 = Synth.getEffect("DRY");

inline function onMasterKnobControl(component, value)
{
    // Normalize value to 0–1 range
    local normValue = value / 127.0;
   
    // Map WET: 0 → -100dB, 1 → +18dB
    local wetGain = normValue * 127 - 0;
    
    // Map DRY: 0 → +18dB, 1 → -100dB (inverted)
    local dryGain = (1 - wetGain) - normValue * 0 - 101;

    FX1.setAttribute(FX1.Gain, wetGain);
    FX2.setAttribute(FX2.Gain, dryGain);
}
   
Content.getComponent("wetdryknob").setControlCallback(onMasterKnobControl);

Lindon

@Jeetender use an RMS calculation.

Jeetender

@Lindon How

const var wetdryknob = Content.getComponent("wetdryknob");
const var FX_WET = Synth.getEffect("WET");
const var FX_DRY = Synth.getEffect("DRY");

inline function onWetDryControl(component, value)
{
    local wetMix = value / 127.0;
    local dryMix = 1.0 - wetMix;

    local wetGain = Math.sin(wetMix * Math.PI * 0.5);
    local dryGain = Math.cos(dryMix * Math.PI * 0.5);

     wetGain = Math.max(wetGain, 0.0001);
    dryGain = Math.max(dryGain, 0.0001);

    local wetDb = Engine.getDecibelsForGainFactor(wetGain);
    local dryDb = Engine.getDecibelsForGainFactor(dryGain);

     FX_WET.setAttribute(FX_WET.Gain, wetDb);
    FX_DRY.setAttribute(FX_DRY.Gain, dryDb);
}

wetdryknob.setControlCallback(onWetDryControl);```

David Healey

@Jeetender said in Rms type or Cosine type Crossfade Curves:

i have a wet and and dry module in HISE

Can you tell me more about what you are doing because there might be an easier way to achieve what you want.

Jeetender

@David-Healey iam just trying to create a wet dry balance between the two gain modules. iam not using scriptfx node. the earlier script moved the knobs in opposite direction but it was checking the peak volume, so at 50% the overall gain would just goo silent..

David Healey

@Jeetender Have you tried using the send container and send effect for this instead?

Jeetender

@David-Healey no i did not, but the thing is there, i still have to balance between the send or wet with Dry. there is no direct wet dry balance in the modules...

David Healey

@Jeetender What about setting the Gain of the SimpleGain where you want it and using a CC modulator to control the actual value (you can connect the Default value knob to a UI knob, you don't actually need to use a CC). Then you could set any shape you want using the modulation tables.

griffinboy

@Jeetender

Wet / Dry balance is done using a sin / cosine curve usually.
You don't need to do any RMS calculations for an equal power curve.

griffinboy

@Jeetender

This is pseudo code.
It's something like this

// Equal-power wet/dry crossfade (pseudocode)

// knob range
value = 0 to 127

// normalize
t = value / 127.0


// equal-power law
// sin/cos keep total power constant
wet_lin = sin(t * PI * 0.5)
dry_lin = cos(t * PI * 0.5)


// linear → dB
// dB = 20 * log10(gain)
// log10(x) = ln(x) / ln(10)

wet_db = 20 * ln(wet_lin) / ln(10)
dry_db = 20 * ln(dry_lin) / ln(10)


// clamp near zero (avoid -inf)
if (wet_lin < 0.00001) wet_db = -100
if (dry_lin < 0.00001) dry_db = -100


// apply
WET.Gain = wet_db
DRY.Gain = dry_db



/*
Behaviour:

t=0
dry=1.0  (0 dB)
wet=0.0  (-inf)

t=0.5
dry≈0.707 (-3 dB)
wet≈0.707 (-3 dB)

Summed signal power stays constant across the crossfade,
so the centre position does not sound quieter.

This is the kind of question that AI can help you understand.
Ask chat gpt about it until you get why it works!

Jeetender

@David-Healey this works good but still the same issue, at 50% the volume is not constant.

said in Rms type or Cosine type Crossfade Curves:

@Jeetender What about setting the Gain of the SimpleGain where you want it and using a CC modulator to control the actual value (you can connect the Default value knob to a UI knob, you don't actually need to use a CC). Then you could set any shape you want using the modulation tables.

David Healey

@Jeetender said in Rms type or Cosine type Crossfade Curves:

this works good but still the same issue, at 50% the volume is not constant.

Have you used an equal power curve?

Jeetender

@griffinboy chatgpt or other bots aren't familiar with HISE coding yet i believe.. they just get confused with parameters.

said in Rms type or Cosine type Crossfade Curves:

@Jeetender

This is pseudo code.
It's something like this

// Equal-power wet/dry crossfade (pseudocode)

// knob range
value = 0 to 127

// normalize
t = value / 127.0


// equal-power law
// sin/cos keep total power constant
wet_lin = sin(t * PI * 0.5)
dry_lin = cos(t * PI * 0.5)


// linear → dB
// dB = 20 * log10(gain)
// log10(x) = ln(x) / ln(10)

wet_db = 20 * ln(wet_lin) / ln(10)
dry_db = 20 * ln(dry_lin) / ln(10)


// clamp near zero (avoid -inf)
if (wet_lin < 0.00001) wet_db = -100
if (dry_lin < 0.00001) dry_db = -100


// apply
WET.Gain = wet_db
DRY.Gain = dry_db



/*
Behaviour:

t=0
dry=1.0  (0 dB)
wet=0.0  (-inf)

t=0.5
dry≈0.707 (-3 dB)
wet≈0.707 (-3 dB)

Summed signal power stays constant across the crossfade,
so the centre position does not sound quieter.

This is the kind of question that AI can help you understand.
Ask chat gpt about it until you get why it works!

griffinboy

@Jeetender

Right but the math works the same way.
All you need to do is find the right hise functions in the API for the math calls.

Lindon

@Jeetender eaiest way is ro use a scriptnode network and a xfade module...

Rms type or Cosine type Crossfade Curves

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