The beating of 2 frequencies, can it be extracted?

#1

Apologies if this is a newbie question, but is it possible to isolate the beating of 2 frequencies as an individual signal for triggering other activities' within the patch ?
Thanks in advance..

How to Binaural beats
#2

Have you tried inverting one of the oscillators?

Not sure what objects are available for this, but thought something like that should be easy enough.

#3

Hmm... interesting idea. If we're talking sine waves with complete cancellation when they're 180 degrees out, maybe an envelope follower can be used? If the beating is slow enough obviously.

EDIT: It should work somewhat with square waves and triangle waves too because symmetrical waves only contain odd harmonics so they all cancel each other out at 180 degrees. Saws might work too if you invert one of them (as jimmy_p suggests), it'll produce a pulse wave with a width that cycles at a rate determined by the frequency difference between the two oscillators. If I understand correctly how envelope followers work then that should get a changing level too (high as the PW is 50% and low as it crosses over from 100% to 0%).

#4

You could subtract one frequency from the other, then use that frequency for an LFO.

#5

Thanks for the thoughts,
I discovered last night that when viewing the signals on the spectral viewer, the bottom 3 levels shown signs of the beating, I'm guessing if it was possible to extract the values from these 3 levels and add them together, this would produce a noticeable value to work with ? I haven't learnt to program the modules yet so not sure how I would do this...

#6

Hey there ! see this thread https://sebiik.github.io/community.axoloti.com.backup/t/how-to-binaural-beats/3092/4

#7

The beating effect is close frequencies cancelling each other out and thus causing amplitude modulation. What you need therefore to use this modulating amplitude as a control source is an envelope follower.

#8

If I remember correctly, the beating frequency is the highest frequency minus the lower frequency.
443Hz - 440Hz = 3Hz

#9

@Gavin it is working
contributions/phi/patches/binauralbeatsextraxtion

grafik.png1382x792 68.4 KB

If you play with with center you can also extract more beatings

#10

Wow, thats incredible, nothing like how I thought it could be done. Will have to play around with it and see what I can do.
I've come along way since I started this post nearly a year ago, but I still feel like a newbie at times.. !
:grin: