First VST : Reverse Delay | Algorithm Design | Forum

double DelayGainCalculator::processAudioSample(double xn)
{
	// --- calc threshold
	const double threshValue = pow(10.0, parameters.threshold_dB / 20.0);
	const double deltaValue = xn - threshValue;
 
	const double wetGainMin = pow(10.0, parameters.wetGainMin_dB / 20.0);
	const double wetGainMax = pow(10.0, parameters.wetGainMax_dB / 20.0);
 
 double yn = 1.0;
 // --- if above the threshold, modulate the filter fc
	if (deltaValue > 0.0) // || delta_dB > 0.0)
	{
		// --- best results are with linear values when detector is in dB mode
		double modulatorValue = (deltaValue * parameters.sensitivity);
        boundValue(modulatorValue, wetGainMin, wetGainMax);
        yn = modulatorValue;
	}
 
    return yn;
}

 

// EnvelopeDetectorSideChainSignalProcessor.processAudioSample (called from AudioDelay's processAudioSample method):

    double processAudioSample(double xn) override
    {
        // Amplify signal by sideChainGain
        const double sideChainGain = pow(10.0, parameters.sideChainGain_dB / 20.0);
        xn *= sideChainGain;
 
        // --- detect the signal
	    const double detect_dB = envDetector.processAudioSample(xn);
	    const double detectValue = pow(10.0, detect_dB / 20.0);
 
        // Pass it through Delay Gain Calculator
        const double yn = delayGainCalculator.processAudioSample(detectValue);
 
        return 1 - yn;
    }

 

double EnvelopeDetectorSideChainSignalProcessor::processAudioSample(double xn) override {
     // Amplify signal by sideChainGain
     xn *= sideChainGain;
     // --- detect the signal
     const double detect_dB = envDetector.processAudioSample(xn);
     const double detectValue = pow(10.0, detect_dB * 0.05);
     // Pass it through Delay Gain Calculator
     const double yn = delayGainCalculator.processAudioSample(detectValue);
     return yn;
 }

double DelayGainCalculator::processAudioSample(double xn)
{
    // If above the threshold, attenuate the wet mix by the wetGainMin factor
    double yn = wetGainMin;
    if (xn < threshValue)
    {
        // if below the threshold, amplify the wet mix
        yn = xn * parameters.sensitivity;
        // Keep within min & max wet gain bounds
        boundValue(yn, wetGainMin, wetGainMax);
    }
 
    return yn;
}