Let's Design and Build a (mostly) Digital Theremin!

I wonder what our old pal Touchless is up to these days?  Last seen November 9, 2019.  Anyone ever visit his "Classic Antiques" shop in Tombstone?  Funny how he and oldtemecula have never been seen together in the same room (though they both addressed Amethyste in one thread).  They both live in AZ, you'd think they would have gotten together by now.  Amazingly, they both talk about the same things, both use a 555 on their volume circuits, etc.  I kinda miss Touchless hectoring me for a sound sample, saying my Theremin sounds like a cheap tin whistle, hollering at me for researching too much, though oldtemecula is doing his best to fill the void he left.  If you can read this, I hope you're doing OK Touchless, wherever you are.  Don't forget the folks here at TW, and all the fun you had with them.

[EDIT] Touchless, if you don't want to come back to TW I understand, but could you maybe get a word or two back to us on how you're doing through oldemecula? 

That touchless story touched my heart. I apologize for being a dick, we have enough of them around here.

Christopher

Finally your thread that I avoided out of respect has become entertaining.

"That touchless story touched my heart."  - oldtemecula

Have you heard anything from Touchless?  I'm really worried about him.  You guys should probably meet each other anyway, you have so much in common it's downright eerie.  Touchless did big meaningless picture posts too, you're making me feel like he's here somehow.

"I apologize for being a dick..." - oldtemecula

You shouldn't beat yourself up, Touchless was a giant dick, and those are big shoes to fill.

"... we have enough of them around here."

Not since Touchless left, but I know you're doing your best to cover for him.

Do you think he's OK?

I just had the terrible thought that Touchless might be in the hospital.  His brain never worked all that well in the first place, so they could easily think he's brain dead and pull the plug.  Oh dear.

Cello 2

I pulled up some cello samples in Audacity and searched by eye for spectral peaks.  The sampled cello has resonances around 119,164, 329, 554, 880, 1108, and 1568 Hz, and I used these frequencies to update my cello patch:

I defeated the oscillator filter as that just thinned things out (the old resonator used to roll off the highs), and gave it some bass emphasis.  Reduced Vmod for the harmonics down so low it could really just be zero.  Didn't spend a lot of time monkeying with the resonator, but did turn it's feedback knob down a little.  See what you think: [MP3].  It's not 100% realistic, and not night and day compared to what I had before, but it seems to be an improvement.  Cello needs some oomph on the low end IMO.

I've been playing with this preset as well to try to fatten the bass, tone down the resonances a bit, and try to make the higher pitches sound a little less vocal.

Your sample has a much more pleasing and fuller bass from what I remember, although there is a little too much peaking somewhere in there, unless that's a recording issue. But beyond that I can't tell how it behaves higher up so I'll set this up tomorrow to play with it a bit.  I had disabled FLT_OSC myself a while back, and now that my other problem is resolved I hope to get on with preset fun and do some A-B comparisons with yours.  This morning I was messing with the resonator as well.  It would be nice to have access to these stringed instruments just to be able to do tap tests to get a better idea of the natural resonances, or maybe something like this already exists out there.  I keep trying the resonator frequency higher and lower, and within reason they both sound okay but if you don't have a good reference you can really start drifting away from the real thing.

I've also reduced the 1108 formant but I see that you've added one at 1568.

Man, those resonances that are so important for the string sound are just brutal for highlighting pitch errors.  I've had to scale back vibrato movements from a wrist-induced forearm movement to about half the displacement, which is tough to do because it has no natural resonance (I'm talking about physical arm movements).  I don't know where the happy medium is for this timbre/playability tradeoff.  I wonder if the natural instrument resonances also mess with player's pitch perception too?

I don't hear much difference between -2 and -1 for "mode".  What is the difference?

Cello v2.0.0.0.1a

The D-Lev has 8 formants and my cello patch was only using 6, and now 7, so just for the heck of it I guesstimated the inter-formant distance and added one to the top end at 1975 Hz, at the same level (levl = 48) as the others.  It makes a noticeable and IMO positive difference, as it opens up the top end (adds "air" as audiophiles like to say) and makes the pseudo stereo effect somewhat more pronounced.  A quick sample (with some added reverb, sorry couldn't help myself): [MP3].  Roger, I'll send you the *.dlp file in a sec.

"Your sample has a much more pleasing and fuller bass from what I remember, although there is a little too much peaking somewhere in there, unless that's a recording issue."  - pitts8rh

I run pretty close to the rails when recording, so it's probably that?

"It would be nice to have access to these stringed instruments just to be able to do tap tests to get a better idea of the natural resonances, or maybe something like this already exists out there."

IIRC, one older paper excited the modes by driving the strings with an electromagnet, sort of an inside out electric guitar setup.  Tapping (impulse response) should give the resonances, but you have to trust how they massage the data.

I've found it's pretty easy to just eyeball the resonances of a decent anechoic recording.  The lowest notes have the most harmonics, so you only need to examine the bottom octave or so in order to resolve the major resonance frequencies.  But this doesn't give you Q's or levels, and it would be nice to have all of this analysis and synthesis more scientific and nailed down and automatic.

"I keep trying the resonator frequency higher and lower, and within reason they both sound okay but if you don't have a good reference you can really start drifting away from the real thing."

The resonator is a crazy thing, using it is unfortunately largely a monte-carlo effort.  The way it can do OK human vocals with no other filtering assist was a real shocker.

"Man, those resonances that are so important for the string sound are just brutal for highlighting pitch errors.  I've had to scale back vibrato movements from a wrist-induced forearm movement to about half the displacement, which is tough to do because it has no natural resonance (I'm talking about physical arm movements).  I don't know where the happy medium is for this timbre/playability tradeoff.  I wonder if the natural instrument resonances also mess with player's pitch perception too?"

I know what you mean.  When coming off of playing the ultra-pitch-forgiving whistle for a while to the cello I go instantly from a B- student to D+.  Stringed instruments generally have a slower vibrato than my natural arm/hand resonance, so that's been difficult to remember and do.  And it's been a real challenge, particularly on the violin patch, to get rid of (i.e. dial out of the patch) those strange squeaky sounds that vibrato accentuates.  I wonder if the resonance frequencies themselves cause players to go sharp or flat when playing notes that run counter to them?

"I don't hear much difference between -2 and -1 for "mode".  What is the difference?"

In the more recent SW (since 2020-05-30) the resonator modes go like this (before that + and - were swapped, sorry for any confusion):
  2 : serial pseudo stereo
  1 : serial (reverb)
  0 : formant bypass (variable w/xmix)
 -1 : parallel (formant fill)
 -2 : parallel pseudo stereo

So if you are monitoring in stereo, I'd use mode -2 for the string patches.

"I don't hear much difference between -2 and -1 for "mode".  What is the difference?"

In the more recent SW (since 2020-05-30) the resonator modes go like this (before that + and - were swapped, sorry for any confusion):
  2 : serial pseudo stereo
  1 : serial (reverb)
  0 : formant bypass (variable w/xmix)
 -1 : parallel (formant fill)
 -2 : parallel pseudo stereo
So if you are monitoring in stereo, I'd use mode -2 for the string patches.

Therein lies the problem.  I'm still playing in mono.  After all of the rework to retrofit to stereo I am still short a cable needed to get the second channel back to the mixer.  Note to self.

"Therein lies the problem.  I'm still playing in mono.  After all of the rework to retrofit to stereo I am still short a cable needed to get the second channel back to the mixer."  - pitts8rh

Hey mister!  *picks 1/2 cello up off the floor*  You forgot this!  ;-)