MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

down the rabbit hole of shepard tones
MUFF WIGGLER Forum Index -> Modular Synth General Discussion  
Author down the rabbit hole of shepard tones
dude
so i started trying to patch a shepard tone last night after a geek conversation at a brunch yesterday. i went immediately home after the get-together to patch up the idea. i got a little too close and have been a bit obsessive about it. i wonder which of you has made the analog shepard tone a reality and who can help me find the right patch. it appears the ideal is a bunch of vcos. i was trying to use two vcos, a quadrature lfo and 1 vca per voice. it came really close. d'oh!
dude
i tried doing some searches here and other places.
Babaluma
i can get a very nice shepherd tone effect from my synthsonic/mfos phaser, if i use a very slow rising or falling sawtooth LFO to modulate the phase, and have it in 8 stage phaser mode, that gives you 8 notches rising or falling through the harmonic series and sounds very nice.

other than that, i think you are gonna need a lot of vcos and quadrature lfo's if you want to create it just with tones.
Just me
Wikipedia has all the info you need to try it and if the Dot.com wiki was up, there was a patch there that came close without the quadrature LFo's.
A Dingleberry Monstrosity
this is where you have a tone that appears to be constantly falling or rising?

I can do it with my doepfer 188 and cwejman fsh-1 It's peanut butter jelly time!

I cant with my doepfer 188 and doepfer freq shifter. sad banana
ndkent
The classic effect always involves several coordinated copies of a patch. I am kind of curious about claims of not using more than one phaser, oscillator, or whatever and would be curious to hear the specifics of what's going on to give you a continuous rise or fall.

The barber pole analogy is accurate to a point. It looks like the stripes are going upward (though it could be reversed). The trick involved is you are only seeing one side of it. The analogy there is a fade in and a fade out as it goes around the back, though unlike a real barber pole you aren't hiding the sound 50% of the time.

So imagine a rising sawtooth. If you fade out the fall you don't hear it. What you get is a looped rising sound with a softened gap from the fade rather than hearing the fall. The idea is you have another copy of the same thing in a different phase so the gaps don't occur at the same time. But you can't get away with only 2 because it's too exposed and you still hear something going on with the fades. The more copies you run doing that at different phases the more the fact there is a fade is hidden. How many is sort of a call.

What sells the effect is something psycho-acoustic. We hear octaves in a special way from other intervals. So if you have a few different octaves going you are still following a single pitch mentally. If you did a fade out and in on several different non-octave notes you could follow a particular pitch disappear. But the octave relationship of several overlaid just sounds like a rise in composite
dude
i was using a mankato as the modulator to both vcos pitch and vcas. i used 0 and 180 degree outs for pitch to vco and then 90 and 270 degree outs (in order only to hear the rise) of the vca amplitude. it was the beginning of the effect but the edges were a little to obvious. i think if i could double that somehow then it would be a success but the trouble is that the mank doesn't sync. oh fuck, i think i may have just figured it out. i could sync another lfo from the mankato and use that to get two more voices in there. anyway the guy i was having the conversation with which started this mess is coming over bright and early and tomorrow morning and at least now i have a little more idea of how it can be done. i don't currently have enough vcos but i think i will find a way to get sound sources from, maybe a noisering and some lfos or maths or something.

thinking out loud.
Lyonel
Great post Nicholas thumbs up
Synthbuilder
I've cheated in the past. I use one channel, one VCO (or phaser) and one modulating source and then use a sampler to regurgitate multiple takes of it at the correct points.

If using a DAW it's even easier - you can modulate the VCO or phaser from a pre-programmed midi CC CV out and cut and paste the subsequent recorded audio output over again and on top of each other.

My last attempt at barber pole phasing - it runs as a drone through the first part of the track:



No I didn't do the video. That the chap put a load of religious iconography on it serves me right for calling the track 'Sanctuary'.

Of course, I was talking about a seal sanctuary... hihi

Tony
kindredlost
There is a pseudo-shepard tone patch using three osc's, a mixer and amp to generate more of a rising ro decending tone illusion at the synthesizerscom Yahoo group. Look in the "Files" section under the "Patches" folder.

I've used this many times. It can provide a good approximation of a barber pole effect, but I find it more fun to get those cool 2001 A Space Odessey pod sonar sounds.

content credits to Yahoo username studio1dk

Tim Stinchcombe
I've been meaning to give this a go for a long time too, and have slowly been buying second-hand A-110s to be able to do it. I have a requisite number now (at least 8 seems to be 'the norm' for a good effect), and 8 simple VCAs should be easy enough to build on some strip board. Several books on psycho-acoustics I have mention it, and from memory, the shape of the VCA curves can be quite critical in getting the effect 'just so'. In any case, generating the ramps and triwaves (for VCOs/VCAs resp) should be easy enough with this circuit:

http://hammer.ampage.org/files/quad-shep.pdf

which looks pretty simple, and though its a long while since I read it, I assume that it might be easy enough to modify it to 'weight' each bit being added so as to enable a different shape for the triwaves, to open/close the VCAs in perhaps a log- or reverse log-type way. The biggest obstacle is merely (!) finding the time to do it amongst everything else...

Tim
dude
we got fairly close using 4 vcos, 4vca and a modcan 66b control module to draw the vca control voltage curves by hand. it was damn close by the end but there was always an audible reset point to the 'loop'. it was close enough that i called it good lol. thanks for all the thoughts. maybe the dotcom patch approach on a rainy day.
stephenmendes
my Shepard scale patch

https://youtu.be/GGkrvyR0STs

my Shepard-Risset glissando (descending)

https://youtu.be/RJqtNy9yOIE

and this one shows how to change the descending glissando into an ascending one

https://youtu.be/JDxoQhYr1SA
Rob_C
In 1983 PAIA sold an experimenters kit (EK-9) for generating Shepard tones. You may find John Simonton's "Lab Notes" article on Shepard tones helpful. The PDF document is provided via a dropbox link from the website of Marvin Jones, a former PAIA product designer and author. [The article originally appeared in Polyphony magazine, but this reprint corrects some errors.]

Link ->Lab Notes Shepard Functions by John Simonton

EDIT: I see Tim Stinchcombe has already posted the original Polyphony article in his Wed Jun 16, 2010 post, along with an article by Tom Henry.
widdly
I wonder if you could do it with four envelopes. If you had a four step sequencer and trigger each envelope from a different step. Then you adjust all the decay and release to give a slope matching the complete sequence length. Feed the outputs to 4 VCO's fm inputs and adjust each so the sweep is exactly one octave. It would requires some careful tweaking and a scope would certainly help.

I might go and try it out!
brandonblaps
Maybe this can help you...
https://www.youtube.com/watch?v=bRF-o0ghrmA&t=60s
flo
It can be easily patched using a quadrature LFO that provides both sine and saw outputs at the same time - such as the new-ish Cwejman PH8 (this thread is old!). Here is an example with it and a QMMF4 and VCA4MX to provide the oscs and VCAs (could have been done with the internal QMMF4 VCAs, but was easier to dial in like this).

[soundcloud url="https://api.soundcloud.com/tracks/294488504" params="color=ff5500&auto_play=false&hide_related=false&show_comments= true&show_user=true&show_reposts=false" width="100%" height="166" iframe="true" /]

https://soundcloud.com/contracommunemopinionem/nov-16-barbepole-feedba ck-fm

There are some further twists to the patch, like feedback FM on the whole osc bank that I dial in about halfway through the recording... As always, patch details can be found on Soundcloud or in my patching thread. thumbs up

Cheers Guinness ftw!
dubonaire
flo
That's... a lot of Dixies eek!
peripatitis
flo wrote:
It can be easily patched using a quadrature LFO that provides both sine and saw outputs at the same time - such as the new-ish Cwejman PH8 (this thread is old!). Here is an example with it and a QMMF4 and VCA4MX to provide the oscs and VCAs (could have been done with the internal QMMF4 VCAs, but was easier to dial in like this).

[soundcloud url="https://api.soundcloud.com/tracks/294488504" params="color=ff5500&auto_play=false&hide_related=false&show_comments= true&show_user=true&show_reposts=false" width="100%" height="166" iframe="true" /]

https://soundcloud.com/contracommunemopinionem/nov-16-barbepole-feedba ck-fm

There are some further twists to the patch, like feedback FM on the whole osc bank that I dial in about halfway through the recording... As always, patch details can be found on Soundcloud or in my patching thread. thumbs up

Cheers Guinness ftw!


good stuff!

we should probably ask Hans Zimmer this thing is all over his Nolan soundtracks
flo
Thanks! SlayerBadger!

If you can get him to chime in, sure! hihi Probably there's some plugin for instant barberpole gratification wink

Cheers Guinness ftw!
MUFF WIGGLER Forum Index -> Modular Synth General Discussion  
Page 1 of 1
Powered by phpBB © phpBB Group