Metric Halo Thump - Manual (Page 22)

Processing
22
Each Amplitude Follower functions as an envelope detector that is driven by the input audio signal. The
Amplitude Follower extracts the amplitude envelope from the signal. Each Amplitude Follower provides the
following controls that you can use to control it's behavior:
• The Envelope Atk. and Pitch Atk. controls set the attack time constant in milliseconds (ms) of their
respective Amplitude followers. The attack time constant controls how quickly the envelope output
increases when the level of the input signal is higher than than the envelope output. Smaller values cause
the envelope to follow the signal more closely, but values that are too small could lead to distortion,
depending on the characteristics of the input signal.
• The Envelope Sust. and Pitch Sust. controls set the release time constant in milliseconds (ms) of their
respective Amplitude followers. The release time constant controls how quickly the envelope output
decreases when the level of the input signal is lower than than the envelope output. Smaller values cause
the envelope to follow the signal more closely, but values that are too small could lead to distortion,
depending on the characteristics of the input signal.
Oscillators
The envelope outputs from the Amplitude Followers are used to control the two oscillators that make up
Thump's synthesis section. Each oscillator has two controls to allow you to adjust how the frequency of the
oscillator changes with the control input from the Pitch Amplitude Follower:
• Atk. Frequency: This control sets the frequency of the oscillator when the Pitch Amplitude Follower
output is at its maximum value (e.g. the input signal is at full-scale). This control ranges from 1 to 440 Hz.
• Sust. Frequency: This control sets the frequency of the oscillator when the Pitch Amplitude Follower
output is at its minimum value (e.g. the input signal is silent). This control ranges from 1 to 440 Hz.
As the output of the Pitch Amplitude Follower swings from its minimum value to its maximum value, the
oscillator's frequency will swing from the value set by the Sust. Freq. to the value set by the Atk. Freq. Each of
the controls can take any value in the range, so that the oscillator frequency can be decreasing as the signal
decays away, increasing as the signal decays away or even constant (if both controls are set to the same value).
The traditional decaying pitch drum sound can be made by setting the attack frequency higher than the sustain
frequency. The frequency characteristics of each oscillator can be set independently.
The output of the Envelope Amplitude Follower is used to control the amplitude envelope of the output of the
oscillators. The overall amplitude of each oscillator is independently controlled by its associated mix param-
eter. By adjusting the Env Atk. and Env Sust. parameters you can control how audible the attack frequency
sweep is, and how long the decay of the sound will continue to be audible.
The oscillators have two master controls:
• Enable: This button turns each oscillator on and off.
• Mix: this fade sets the output level of each oscillator, from -∞ to +6 dB.
Output
Thump's output section has two controls:
• Wet/Dry Mix: This controls the balance between the original signal and synthesized audio. 0% is full
dry (no effect), 50% is equal balance and 100% is full effect (no original audio). If you are using Thump
on an aux bus, you would traditionally set the Wet/Dry Mix to 100.
• Out Gain: This sets the final output level of Thump, and ranges from -24 to +24 dB.