Question about `juce::ADSR::calculateRates` method


#1

I was studying the sources of the ADSR class and noticed something: am I right to think it should be

attackRate  = (parameters.attack  > 0.0f ? static_cast<float> (1.0f / (parameters.attack * sr))  : -1.0f);
decayRate   = (parameters.decay   > 0.0f ? static_cast<float> ((1.0f - sustainLevel) / (parameters.decay * sr))   : -1.0f);
releaseRate = (parameters.release > 0.0f ? static_cast<float> (sustainLevel / (parameters.release * sr)) : -1.0f);

rather than:

attackRate  = (parameters.attack  > 0.0f ? static_cast<float> (1.0f / (parameters.attack * sr))  : -1.0f);
decayRate   = (parameters.decay   > 0.0f ? static_cast<float> (1.0f / (parameters.decay * sr))   : -1.0f);
releaseRate = (parameters.release > 0.0f ? static_cast<float> (1.0f / (parameters.release * sr)) : -1.0f);

?

That is: in the attack stage, amplitude goes from 0 to 1, so we “split” the range (1 in this case) according to the attack duration (expressed in n. of samples). For the decay stage, amplitude goes from 1 to the sustain level, so we split the range (1 - sustainLevel) according to the decay duration, and so on… Instead, it looks like the original code always uses 1. I tried to make the change locally and it seems to work just fine…


#2

Yep, I’ll get that fixed.