Multi-channel nonlinear processing of a single musical instrument signal
Multiple channels simultaneously provide multiple, modified digital audio signals, respectively, based on the same digital audio input signal. Each channel has a respective nonlinear effects section to apply a nonlinear transfer function, such as one that emulates a vacuum tube guitar amplifier, based on the input signal. In addition, a respective audio effects section is provided in each channel to apply an audio effect, such as a linear audio effect, based on the input signal. This audio effect is set in each channel by a controller. In another embodiment, multi-tracker (e.g., double tracker) functionality is provided by the multiple channels wherein at least one of the delay effect, pitch shift, and gain change in a channel is automatically changed as a function of the input signal.
1. A method comprising:
simultaneously generating first and second digital audio signals based on the same digital audio input signal, the first digital audio signal being generated by one of (1) delaying the digital audio input signal in accordance with a random variable delay amount, (2) randomly changing a pitch of the first digital audio signal relative to that of the digital audio input signal, and (3) randomly changing a gain factor of the first digital audio signal, as a function of the digital audio input signal; and
generating a sound that reflects a combination of the first and second digital audio signals.
2. The method of claim 1 wherein one of changing the variable delay amount, changing the pitch, and changing the gain factor is in response to detecting an attack in the digital audio input signal.
3. The method of claim 2 wherein the digital audio input signal is a digitized electric guitar signal.
4. The method of claim 1 wherein the first digital audio signal is generated according to a plurality of parameters that control the delaying, pitch changing, and gain changing, and wherein none of the plurality of parameters is changed unless an attack is detected in the digital audio input signal.
5. The method of claim 1 wherein the first digital audio signal is generated according to a plurality of randomly distributed parameters that control the delaying, pitch changing, and gain changing.