Turning a Fixed Filter Bank Into a Modulated Filter

JH posted the following to AH. He gave me the ok to put it up here. Title link takes you to a 7M WAV. Enjoy.

"I've just finished an experiment of using two Frequency Shifters to turn a Fixed Filter Bank into something animated, modulated.

A drone sound from the OB-8 is sent to a first Frequency Shifter, which shifts the audio signal up by a variable amount of Hz.

This upshifted signal is sent thru a filter bank (MAM vocoder, with a rather thin-sounding setting with all even channels up and all odd channels down.

This filtered signal is shifted back down with a second Frequency Shifter, by the same amount of Hz that the original signal was shifted up.

First you hear the very thin sounding unshifted signal - just the OB-8 drone processd by the vocoder filter bank.

Then we start to modulate the Frequency Shifter with the Joystick.

link ( 7 MByte - I tried mp3, but it was no good)

Please note that there is no filter modulation! The filter is fixed all the time (static formant filter) - it's the signal that is modulated!

Sorry for the rather low quality of the unmodulated sound - I just made this experiment at 1 am after finishing the hardware. :)

Background about this project: link


Let me know if you have ideas what else could be processed with this. I'll certainly try reverb, and all kinds of fixed filters.

JH."