Description

Hi,

This is a Spectral Convolvor audio effect. It cross synthesizes the Input audio with an FM oscillator. In particular, it convolves the first signal with the Spectral Amplitude of the second, or (if the double arrow button is pressed) it convolves the Spectral Amplitude of the first signal with the audio of the second. These are different.

The FM oscillator has been updated with a patch from the man himself, John Chowning:

https://cycling74.com/forums/carrier-and-harmonicity-in-fm-synthesis

Pitch, Carrier, Modulator and Modulation Index controls are included. The sound is wildly affected by all of these. I included a spectrogram to see what each does to the FM oscillator. You can only really see what is happening for small values of the parameters, but you can tell that a lot of the controls are quasi periodic. As you experiment with small parameter values, you can kind of get an idea of what happens at the larger values. I recommend using the keyboard arrow keys to scan (Shift-arrow to scan faster). The Modulator display might show 222Hz, but if you use the arrow keys, you can usually find several spots before hitting 223hz (you can also type in values like 222.3, each of these usually sound different).

The PreMix controls the amount of each signal (Input and FM) used in the convolution. It kind of acts like a volume knob since the FM Oscillator is at a fixed amplitude and convolution requires two nonzero signals to hear anything.

The Lo and Hi Cut are applied to the Input before convolving with the FM. The Mix knob controls the mix between the Input and the Eq'd/Premixed/Convolved wet signal.

I'm sure there are tons of bugs and alarms going off everywhere. Let me know in the comments and I can try to fix them.

Share and enjoy

Bugfix 1: I fixed the output routing so that it mixes dry and wet correctly.