Freezing an audio slice

#1

Hi!
I'm trying to emulate a guitar pedal on the axo. It's called th EHX freeze (sound retainer), and what it does is to create a drone or pad type of sound upon the press of a momentary switch, by sampling a slice of the input (I guess).
I tried 3 different approaches, they all work, but none gives me the super-clean result of the original;
delay freeze.axp (9.6 KB)
granular freeze.axp (8.8 KB)
convolution freeze.axp (6.6 KB)
and the convolution is a no go, because it takes too much cpu to fit in the big patch I use as a multi-fx...
any DSP ninja out there with advices or a better approach?
Cheers,
Val

#2

I have an EHX Super Ego (effectively a deluxe version of the Freeze) and I have a feeling it might be FFT spectrum analysis and resynthesis (based on the way the portamento effect behaves). It's just a guess though.
I don't know whether the axoloti might manage that with a custom object or whether it might not have enough power.
I haven't loaded your patches because I'm on my phone, but I've had some luck with the infinite reverb type of approach (allpasses and a unity gain feedback loop).

#3

Yep, it might well be so, I found an opensource lv2 plugin called Stuck witch is a very decent emulation of the Freeze and from what I could understand from the code that's FFT...

My delay based freeze is something like that, a windowed chunk of audio and unity gain feedback loop, I ditched allpasses 'cause they sounded metallic, but I now see a TSG one that's modulable, maybe I'll try that approach again... thanks for chiming in!

#4

I haven't tried your patches to compare, but I have been working on this one and like what I'm hearing:

freeeeeeeze!.axp (28.8 KB)

#5

Hi there!
I'll check it out in the evening and report back. :slight_smile:

#6

It works! And sound pretty smooth too, but the main thing I'm missing is the superclean attack of the frozen sound (I use it mostly in a jazzy context, so I'm not aiming at a ambient swell type of sound).
So far the reverb type approach @SirPrimalform suggested is my winner.

#7

Ooh, post some results or the patch itself!

#8

There you go:
comfreeze.axp (16.9 KB)
Sounds best thru a reverb, and the latch mode works differently from the EHX freeze; basically it keeps adding sound as long as you hold the switch and freeze when you release it. A new press will free the buffer.
Enjoy