Imitating pitched white noise from Switched On Bach

In Switched-On Bach, Wendy Carlos often uses a pitched noise sound at a couple octaves above the main note, or so my ear tells me. I know this can be created by running white noise into a high-Q bandpass filter, which I have attempted to do, but I’m having trouble having the filter frequency follow the keyboard at two octaves above. I’m getting a pitch from the noise that sounds maybe two octaves and a third above, just guessing. How does the key follow work on the bandpass filter?

Hi @Mike1127 and welcome to the community.

Can you post an example from Wendy Carlos switched on Bach? That might help.

I’m not sure what you mean. Are you sure it’s noise and not Ring modulation, FM or even the Bodefilter used?

Noise it it self does’nt have any pitch. It can be filtered. And yes a filter can be modulated by the Keyboard follow.
You can read about Keyboard follow settings in the manual section “4.4.1 Keyboard follow management”.

A Filter have K1-K4 settings in the bottom display of the filter. This select the Keyfollow 1-4 as filter modulator. You can also route the Keyboard follows from the synth third section, that you can see and read about in the manual section “4.3 Third Section”.

I’m doing pretty well imitating the sound by putting white noise into the bandpass (multimode) filter with “resonance” cranked all the way to 20. The problem is getting the center frequency of the filter to be in tune with the keyboard. I figured out part of it… set the K2 follow center frequency to something like A3, double-click on the filter’s frequency knob to put it in the center location, and select K2 as the filter’s follow. Then I get noise that’s about an octave above the key. However, it’s still detuned slightly, so the center frequency isn’t quite following exactly the keyboard.

So it’s about the pitch of the filter/ resonance.
I can suggest you let the Keyboard Follow stay at default setting.
Then try to set the Cutoff Frequency to a Hz that match a C note. Like ie 2093 Hz.
At least as a start.

yes, that actually gets much more in tune. The filter frequency knob has a setting close to 2093. It can be set to 2089.9. Enough in tune to not be noticeable.

I assume you consider this solved then.

Yes, thank you.