[sdiy] frequency shifter

[Matthias Herrmann]

Thomas Henry did this with his 1982 “PAL Filter”. And by mixing the original signal into the filtered signal you can mimik both pitch-shift and frequency shift effect. I am currently building his filter and wil soon be able to check this with my own ears.

The effect is shortly discussed here:
https://www.uaudio.de/blog/allpass-filters/

Cheers,
Matthias



From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of ColinMuirDorward
Sent: Wednesday, March 11, 2020 3:01 AM
To: *SYNTH DIY <Synth-diy at synth-diy.org>
Subject: [sdiy] frequency shifter

Hi, I got a little lost trying to understand what a frequency shifter is. I mean the pre-digital method used by Moog (I think?).
I recently built a 4pole APF, and was really impressed with some of the pitching effects I could achieve with it. I'm guessing this is an entirely different method than the frequency shifters like Moog and JH have done.
Is the APF method used by anyone? What are its limitations, and what is it even doing?
Well, I guess I'm just looking for some conversation on the topic of analog frequency/pitch shifting methods. If anyone has any thoughts/experience they'd like to share.
Cheers,
Colin


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