EFM1 provides the following level controls.
Sub Osc Level knob: Introduce a sub-oscillator signal that enhances bass response. EFM1 features a sine wave sub-oscillator. This operates one octave below the FM engine, as determined by the Transpose parameter. Increase the Sub Osc Level control to mix the sub-oscillator sine wave with the FM engine output.
Stereo Detune knob: Add a chorus-like effect to the sound. This is achieved by doubling the EFM1 voice with a secondary, detuned FM engine. High values result in a wide stereo effect being added to the detuning, thus increasing the perceived space and width of your sound.
Note: It is possible that mono compatibility could be lost with use of this parameter.
Volume Envelope: Shapes the level of the sound over time. The volume envelope is triggered every time a MIDI note is received.
Attack slider: Set the time it takes to reach the maximum volume level.
Decay slider: Set the time it takes to reach the sustain level.
Sustain slider: Set a level that is held until the MIDI note is released.
Release slider: Set the time required to reach a level of zero, after the MIDI note has been released.
Main Level knob: Set the overall output level.
Velocity knob: Determine the sensitivity to incoming MIDI velocity messages. EFM1 dynamically reacts to MIDI velocity—harder playing results in a brighter and louder sound. Set the Velocity control all the way to the left—counterclockwise—if you don’t want EFM1 to respond to velocity.