sympathetic oscillators?

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Unfiltered

sympathetic oscillators?

Post by Unfiltered » Sat Jul 10, 2010 9:57 pm

I recently saw a guy playng a bazantar, an upright bass fitted with sympathetic strings, like a sitar. It got me thinking about oscillators, and how I could produce the same effect with a voyager and maybe some extra oscillators. I would just need one or two oscillators to track pitch, and then the others would trigger at various volumes depending on the note played. I know this is possible if not with cv then midi, but I would like to keep it analog if possible. This would most likely involve an envelope follower but that's all I got. Any ideas?

"Strings or parts of strings may resonate at their fundamental or harmonic frequencies when other strings are sounded. In general, non-played strings respond in sympathy to other strings being played. Two tones of the same pitch will give maximum sympathetic resonance as all harmonics of both strings will overlap. Other harmonic combinations will cause sympathetic resonance at the fifth, fourth and major third. For example, an A string at 440 Hz will cause an E string at 330 Hz to resonate, because they share an overtone of 1320 Hz (third overtone of A and fourth overtone of E)."

Sweep
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Re: sympathetic oscillators?

Post by Sweep » Sun Jul 11, 2010 10:30 am

Sorry I can't answer the technical questions about how to do this, but I do think it's worth saying that I think this is something that could be very significant.

It's taken me a long time to realise why I like some kinds of stringed intruments more than others. The key is sympathetic resonance. A harp or similar multi-stringed intrument always sounds good to me as there's the background resonance happening. I play bowed psaltery and love the way the whole instrument resonates in sympathy with the strings being bowed.

With synths, I use reverb and echo a lot to approximate the movement that happens in sound when different tones are moving across each other, and with polysynths I use long release times a lot for the same reason. Multiple oscillators used in the way you suggest are something I've often thought about, and I'd very much like to see this become a reality.
Websites: http://musicbysweep.com and http://theSynthiMusicSite.infinite9ths.com

EricK
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Re: sympathetic oscillators?

Post by EricK » Sun Jul 11, 2010 1:17 pm

If you had an Osc, env gen and vca you could probably do it. Sympathetic strings basically just drone right, as on the sitar? You are wanting to have an oscillator drone at a particular interval with varying volume levels all you would need to do is trigger it when you needed to.

You could probably do it with the voyager via midi, controlling the mixer of Osc 2 or 3 via midi. Turn it off and on like a madman when you wanted to and tune it to whatever interval. The first patch that I came up with from scratch was a sitar when I got my voyager, it was my first attempt at instrument replication from memory.

It would be hard to get it to trigger on certian notes only automatically without midi, but if you paid attention to what you were playing you could trigger it with a footswitch to some dotcom modules or something. It seems plausable.

Eric
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Sir Nose
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Re: sympathetic oscillators?

Post by Sir Nose » Sun Jul 11, 2010 2:12 pm

A sitar has sympathetic resonnant drones and played drones and of course the fingered strings. The tough part and cool part about resonnant drones is the don't always occur at the fundamental, higher harmonics can be stimulated. I wonder if an octave shiter/ pitch shift effect (or a bank of several set to different intervals and levels) would do the job. The key would be how to trigger certain ones with diferent notes.

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_DemonDan_
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Re: sympathetic oscillators?

Post by _DemonDan_ » Sun Jul 11, 2010 3:33 pm

Sir Nose wrote:The tough part and cool part about resonnant drones is they don't
always occur at the fundamental, higher harmonics can be stimulated.
Hi Sir,

One of the ways that resonance is simulated is with very short delay times
with moderate feedback. The delay time determines the resonant frequency.
So it might be interesting to see if you could accurately get the delay times to
track. One cool benefit of delay resonance is that it will automatically respond
to frequencies that are whole-number multiples of the fundamental frequency.

So I guess if you had 12 different delays set chromatically you could do some
very interesting things.

Just brainstorming here, but I'm wondering what would happen if you fed audio
into a reverb and then fed that into a vocoder that's being controlled by the
original audio signal. It might even be interesting to then feed that into another
reverb. Shifting the frequency bands of the vocoder could result in very interesting
resonances.

Frank Zappa loved the effect of playing or talking next to the strings of a piano
with the sustain pedal down. He called it a "pan-chromatic" reverb.
_ :twisted: _DemonDan_ :twisted: _

jrichoux
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Re: sympathetic oscillators?

Post by jrichoux » Mon Jul 12, 2010 11:26 am

Are you familiar with the String Modeller algorithm on the Eventide H3000 D/SE? It's my favorite for this kind of thing. I don't know of any other implementation of this concept on other Eventide products. If anyone knows of something similar, I would like to know about it. I wonder if it can be programmed on the newer Harmonizers like the 7000 series.
John R

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_DemonDan_
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Re: sympathetic oscillators?

Post by _DemonDan_ » Tue Jul 13, 2010 10:45 am

jrichoux wrote:Are you familiar with the String Modeller algorithm on the Eventide H3000 D/SE?
Hi John,

Were you talking to me? If so, then no, I have not had the opportunity to monkey with
that algorithm. But everything they do is top notch, so I'm sure it's a gas to play with.
_ :twisted: _DemonDan_ :twisted: _

jrichoux
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Re: sympathetic oscillators?

Post by jrichoux » Tue Jul 13, 2010 7:25 pm

Actually, I thought I was addressing the original post of this topic. However, I believe that the Eventide approach is very similar to what you outlined. I don't have my manual handy, but I think it involved 6 all-pass filters. In addition to setting fixed pitches for the drones, they can be altered by midi notes as well. Fun.

Back in 2006 I inquired on the Yahoo Eventide forum as to whether any of the later products can do this and this is the response I received from Italo De Angelis:

"There have been several attempts to create Karplus-Strong synthesys
algorithms in the newer Eventides, from the 4000 to the 8000.
They all work fine...but are different from the String Modeller...mostly in
terms of control.
A skilled programmer could try that but the best way would be to create a
specialized module for it.
As of today String Modeller remains an H3000 classic; every unit hs its own.
The newer Eventides have hundreds...."

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latigid on
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Re: sympathetic oscillators?

Post by latigid on » Thu Jul 15, 2010 5:58 am

OT:

Check out these for sympathetic strings -- WOW!

http://www.ellenfullman.com/Video.html

(Just saw two films, one short on Ellen Fullman, the other on Trimpin. Both amazing and fantastic artists.)

psicolor
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Re: sympathetic oscillators?

Post by psicolor » Tue Jul 27, 2010 4:48 am

I'm currently reading Helmholtz' book about the sensations of tone (which is btw very recommendable).

As far as i understand sympathetic resonance, you could make a sympathetic oscillator by "doubling" your raw signal. One goes to the mixer, the other one into a bandpass filter which passes only one very small frequency band. The filtered signal goes into an envelope follower. the resulting envelope cv must be processed by a lag processor and is then needed to control the volume of your sympathetic oscillator, which has to be tuned to the same frequency as the bandpass filter.

Synth -> BPF -> Env. Follower -> Lag-Processor -> VCA (which attached fixed-frequency oscillator)
http://www.psicolor.de

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