Dual Peak Band Pass Filter

[BobF]

BobsDualPeakBandPass.fsm

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Images.jpg (2.84 KiB) Viewed 20120 times

P.S, sorry about the poor image, it was great till I had to shrink it to fit.

Better Images.zip

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Hello Gang,
Well here’s what I am calling my “Dual Peak Band Pass Filter”, yet it is also a “Formant Filter” as well. It’s basically four 12db state variable filters, two each in series for 24db each. The two 24db filters are both set for lowpass out only and both have their own cut off and resonance controls. When combined by subtraction this gives us a 24db Band Pass filter where each peak can be moved independently of the other and also resonance. Also added is a master center frequency control that moves both peaks in unison. See the images for a better understanding. You can select either 12db or 24db output via the little 12db/24db button and also there is a separate 12db output. The little blue slide switches marked 12db O.S. (offset) add a frequency offset to both the 12db filters and act like fine tuning for each peaks center frequency. The button marked “invert peak 1” in most cases boots the frequency response. There is of course the “FFT Spectrum Display”, that really helps setting up various peak separations (responses). Last, take the time to really play with all the setting, as it can provide a lot of really nice sounds, from standard 24db Band Pass, to unconventional Band Pass, and fun vowel Formant sounds.
NOTE; some settings of high resonance along the low and high frequency can cause feedback like howling. Watch those speakers!
Please, enjoy and leave comments or any mods you would like to suggest!
Later then, BobF…..

[Spogg]

I love it Bob!

Those formant sounds are lovely.

Thank you for sharing and always giving us something new and different. Much appreciated.

Cheers

Spogg

[k brown]

Great work - I've always loved 'formant-y' things. It's the most distinctive aspect of the Synton Syrinx, and was always surprised more synth-makers ( ) didn't do something similar.

[Spogg]

Great work - I've always loved 'formant-y' things. It's the most distinctive aspect of the Synton Syrinx, and was always surprised more synth-makers ( ) didn't do something similar.

Next project kevin?

[k brown]

I did it long ago; called it CyRinx, but if Bob's OK with it, maybe I'll update it with this.

[BobF]

Hi kevin,

Yes you can! Anything I post here can be used by you or anyone else. Wish others would use some of my stuff in there designs, it would be cool to see some of it put to good use.

Later then, BobF.....

[wlangfor@uoguelph.ca]

This is an interesting idea, I'll have to give it a whirl as well

[trogluddite]

I've always had a bit of a thing for vocal formant filters, so I've been enjoying playing with this. With some careful setting up of modulation amounts from a footpedal, it makes some really nice "dipthong" filters (like a "wah-wah", but "aiiee-aiiee", "ow-ow", "yoy -yoy", etc.). The only improvement I would suggest would be a version with just the DSP code in a single module without controls, just so that it's a bit easier to wrap in a new GUI 'skin' without having to poke around inside - but that's not a biggie, as it's not a difficult module for folks to do that for themselves, I don't think.

[BobF]

Thanks Trog,

I am NOT really a coder, so if some kind coder would like to take this on. Hint, hint, MV (and others) you could probably do this in a half hour or so. Combine four 12db State Variables to get two 24 db filters and then do the subtraction all in assembly.

P.S., does anyone think this would be a nice addition to Flowstone 64 bit also, if coded?

Later then, BobF.....