Envelope Follower

1. Attack Knob Sets the envelope follower reaction time on attack.
2. Release Knob Sets the envelope follower reaction time on release.
3. Gain Knob Gain applied to Env output.
4. Output Level Shows the Env output voltage.
5. Inputs Audio signal from which an envelope will be generated (stereo).
6. Env Output Envelope CV signal generated from the input signal.

Overview ⚓︎

The Envelope Follower generates a CV envelope from an audio signal by following the peak of the source. Attack and Release control how fast the peak is followed when the source becomes louder or softer.

Compared to the similar RMS module, the Envelope Follower produces envelope signals that are more dynamic and that better follow the contour of the source. They are a good choice to control a VCA, a Low-pass Gate or a filter cutoff. However, the RMS produces a smoother CV signal and is a better choice in patches where we are interested in the overall loudness of a signal (like a compressor).

Usage ⚓︎

Connect an audio signal to the input. For a mono source, only connect to the leftmost input jack.

When the source is stereo, the Env output will be the average of the left and right channel envelopes.

The reaction time of the envelope follower is set with the Attack and Release knobs. When the peak of the input signal is greater than the current envelope follower output, the module will use the attack time. Otherwise, it will use the release time.

Long time settings will produce a smoother and more stable envelope signal, but will not follow the source amplitude as closely as shorter time settings. In general, very short attack and release times should be avoided unless the input signal has plenty of high-frequency content, and the release time should be at least 10x as long as the attack time.

For some combinations of input signals and attack/release times, the envelope may have a very high rate of small discontinuities as it quickly switches between the attack and release phases. Depending on how the Env output signal is used in the patch, this could be heard as unwanted noise. When this happens, increasing the release time may help. Another solution is to further smooth the Env output by processing it with a Slew Limiter. If everything fails, consider using the smoother RMS module instead.