Sympathetic Resonance

dore_m · 2022-06-19T15:57:09+00:00

So I've been playing around with sympathetic resonance in Garritan and Noire to see how it's handled. I was trying to see how I might be able to implement i...

CyberGene

I wouldn’t advertise myself as Physics major although on paper I have the degree… BTW my degree is in engineering physics and as such I’d just recommend measuring your piano for the actual relative power of partials and use that as hard-coded coefficients 😀

dore_m

CyberGene I’d just recommend measuring your piano for the actual relative power of partials and use that as hard-coded coefficients

Yeah, that was what I was planning for my next sampling project - but someone else's piano. just trying to decide which sympathetic conditions to record.

n-player

The people I would ping are: Jeff Hurchalla, bsntn99, karvala at PianoWorld. The first two have been on PianoWorld this spring, but karvala's profile indicates he has not been to PianoWord for a couple of years.

All three had great analysis and insight on VI noise floors in the PW threads. Jeff was the lead developer for Garritan although he changed careers a few years ago.

I would make a post at PW and/or PM the three.

CyberGene

n-player I recently invited Jeff and he said he might join but I guess he’s been busy.

HZPiano

Hello,

Broken-record me says he loves Modern U, in particular for the resonances that are said to be sampled (as opposed to modeled/synthetically generated) and come across as very natural, musical and hugely pleasant.

Apart from this, I'm afraid I cannot contribute much to the daredevil deep-digging analyses by y'all in this thread!

Cheers and happy musical resonances,

Del Vento

dore_m Here's where others can help @CyberGene @Del Vento @vagfilm ,etc.

dore_m Any physics majors point me in the right direction without having re-take my college courses?

Let's see.

dore_m For me the missing link is the theoretical power equations for the overlapping frequencies. Probably these will all be different depending on what instrument I sample, but I know there is an equation or simplification of the equation that can get me the relative power of the harmonics so I can start out in the correct ballpark without having to re-create every combination manually.

I am not sure I understand your question. The simplified theoretical treatment of sympathetic resonance tells that in the "quiet" string only the harmonics of exact frequencies existing in the "loud" note are excited. Uninteresting. In practice other frequencies are excited too, as your beatings demonstrate (I know, it's a simulation). Which frequencies? Hard to tell and in the extreme case simply everything (just push the damper pedal and hear the "ocean in the seashell" sound).

My suggestion is the same as @vagfilm : record what the acoustic does, comparing a single note with a single note when the damper of another silent one is lifted and check the difference. Not by eye as you are doing in this post, but by actually computing the difference, so you sidestep @vagfilm 's objection of spectrograms hiding the interesting information. Also try the difference between two as-identical-as-possible recordings of the same note, just to get an idea of what is normal recording-to-recording variability.

This is not much, I know, but that's all I can contribute for now (by coincidence, I just found a very old Scientific American article about the science of the sound of the piano which I was already planning to read in the coming days and might provide some insight)

dore_m

Del Vento Not by eye as you are doing in this post, but by actually computing the difference, so you sidestep @vagfilm 's objection of spectrograms hiding the interesting information.

So I create the sympathetic resonance situation by rendering MIDI/Garritan. I have those waveforms. I then use Garritan without the sympathetic resonances and create the harmonics using sine waves in Kontakt, and I get the results in the sound file. Yes, I'm doing it by "sight" using the graphs that I've attached, but I also am using the spectrum analyzer plots where I can measure the difference in amplitude for each partial's frequency. I'm not confused by the spectrogram and spectrum analyzer plots at all. I can see where all of the frequencies are coming from - either open string, or overlapping harmonics between open string and staccato note.

But yes, I need to record a piano in different situations to re-create the partial's amplitudes definitely. It's just a real pain to re-create these with sine waves for each combination unless I had an equation or something to get me close. I can code something to find all of the overlapping harmonics -that seems easy. But guessing the loudness of each resonant frequency and/or matching a recording is very time consuming.

vagfilm

Del Vento by coincidence, I just found a very old Scientific American article about the science of the sound of the piano

Can you share it? I remember one about the physics of singing in the shower and it was a gem...

Del Vento

vagfilm Can you share it? I remember one about the physics of singing in the shower and it was a gem...

Unfortunately I have the paper version of the Italian edition of such article. If you care about it, I think pictures fall under fair use of US copyright.

Otherwise, see https://www.scientificamerican.com/article/the-coupled-motions-of-piano-string/ (but don't forget https://scottaaronson.blog/?p=6202 )

@CyberGene how do I disable URL's preview? I don't like it in this context!

dore_m

After noodling about this a little more, I think situation 1 above (where the open string gets excited by energy from staccato note) is probably unnecessary to re-create/simulate. I'm showing an artificial situation, where the velocity of the open string is 0, but in reality, when you're playing, you'd hold a chord with your left hand and play a staccato note in your right hand. The chord in your left hand would already be ringing out, and not at a 0 velocity. Sure the strings might get excited with more energy from the staccato note, but it's negligible, and the real change in sound would come from the overlapping/resonant harmonics that are simulated by the sine waves.

vagfilm

Hi,

I run a simple resonance test using the VSTs at hand (VSL Steinway, Pianoteq Steinway, Noire, ModernU, Garritan CFX). I have also tested others, but the results were mediocre or not significantly different. This is not to be exaustive, but to give an idea of what is out there.

Since my experience with acoustic grands is limited, I don't know how well implemented the resonances are, but Pianoteq and Noire stand out as the best ones. Noire is really good and the scripting is open for dissection and ideas...

This test was suggested by Charles Cohen in a PianoWorld post #3216573
https://forum.pianoworld.com/ubbthreads.php/topics/3216444/resonance-modelled-resonance-sampled.html

Each WAV file contains 2 sets of 4 notes.

First set (resonance of hold C4):

no silent note + C5 played staccato (midi vel=127, ticks duration=30)
C4 silent + C5 staccato: C5 should continue to sound, as the second harmonic of the open C4 string.
C4 silent + E5 staccato: E6 should be heard, as the fifth harmonic of the open C4 string.
C4 silent + G4 staccato: G5 should be heard, as the third harmonic of the open C4 string.

Second set (resonance of hold C maj inv chord instead of C4 - C4/E4/G3)

no silent notes + C5 played staccato
C chord silent + C5 staccato
C chord silent + E5 staccato
C chord silent + G4 staccato

https://we.tl/t-pYUn91hETR

Drew-r

Asking as a lay pianist/enthusiast, it is difficult for me to get my head around the purpose of comparing or otherwise analyzing sampled resonances (former) versus modeled resonances (latter). My head is sort of reconciled with a Yamaha or Kawai at least being qualified to simulate modeled resonances of their APs, but still wondering how Roland is legitimately qualified.

If the former are produced from recordings of one or more given specific branded models of what actual AP/GPs do sound like, and the latter based on one or more given scientists’ computer algorithms producing an amalgamation of what any hypothetical genetic AP might sound like, is it realistic to expect there is a place the twain may some how meet as apples & apples?

dore_m

That's really helpful. I do like how the harmonics are pretty obvious in Noire's representation, but like the beating effect that happens in Garritan and Pianoteq.

When you hold the C chord, of course the spectrogram gets muddy. My hope is that I can just simulate the resonant harmonics with the sine waves, and when multiple notes are open the script will just trigger more sine waves and end up with the same result roughly as your tests. My son is coding up the harmonic frequency pairs right now (woohoo! Summer Python challenge!) I can share the python with you if you like, although I'm sure you could code it yourself.

Drew-r is it realistic to expect there is a realistic place the twain may some how meet as apples & apples?

Based on my recent research and experimentation in this, I don't think there is much of a hybrid approach. VSL probably uses samples, which creates incredibly large libraries, and Noire uses modeling - which is what I'm attempting more or less. The overlap is in my idea of using a low velocity sample to simulate the open string fundamental harmonics where I wrote:

dore_m I've been noodling about this, and here's my strategy: I mocked up the garritan resonances by doing three things:

I use a low velocity sample of the open string to simulate some of the harmonics of that string (I think these are the frequencies that make Garritan "muddy")
When there are overlapping frequencies between the struck note and the open string, I use sampled sine waves to ala Pianoteq to reinforce those frequencies. I basically made a Kontakt group of sine waves and trigger them by Midi note number according to resonant frequencies. Note, getting the stereo image right is a chore because I have to phase change the L and R channels to match the microphone character. Also, getting the ADSR envelope right also is challenging, but I can get close enough to be encouraged.
EQ filtering - for 1, the primary frequency seems to be too strong, so I EQ'd out the fundamental so the sound is more "ethereal". For 2, I used the LFO to simulate the beating effect.

Otherwise, I can't think of another hybrid way to achieve the resonances.

vagfilm

dore_m VSL probably uses samples

As far as I remember, the number of active voices reported in the VSL GUI is not altered by the onset of symp resonance; that suggests that it is modelled not samples.

dore_m

No kidding. I'm still guessing that sympathetic resonance would take an immense amount of recordings if they did. Wow, they fake it too then…

dore_m

@vagfilm Say, did you use the room mics or close mics to capture the VSL sympathetic resonances? Because I'd expect the mics further away would tend to pic up less of the resonance, which might explain why they are more muted than the others in your recordings.

vagfilm

The VSL recording uses only the condenser close mic; the symp resonance knob is set at maximum value of several dB.

The VSL resonance is indeed less complex than others and of significantly shorter duration. If that is more or less realistic, I have no idea.

dore_m

vagfilm The VSL resonance is indeed less complex than others and of significantly shorter duration. If that is more or less realistic, I have no idea.

Not realistic at all. Unless my piano sustains sympathetic resonances better than a concert grand. I tried your condition 2, and even at a staccato mf, I can get at least 10 seconds of harmonic resonance.

Del Vento

dore_m vagfilm The VSL resonance is indeed less complex than others and of significantly shorter duration. If that is more or less realistic, I have no idea.

Not realistic at all. Unless my piano sustains sympathetic resonances better than a concert grand. I tried your condition 2, and even at a staccato mf, I can get at least 10 seconds of harmonic resonance.

From the acoustic pianos I owned, I second this

CyberGene

Del Vento how do I disable URL's preview? I don't like it in this context!

I believe the author of the post should be able to disable the link preview by clicking on a X button in the preview. However this disables all the previews within that post, not just one of them. And you can’t restore previews in that post once disabled. Let me know if that works. Mods can also do it, but let me know if you can do that too, as author.

vagfilm

Del Vento Unfortunately I have the paper version of the Italian edition of such article. If you care about it, I think pictures fall under fair use of US copyright.

Completely OT, but I will keep it brief. Thanks for title of the article: I downloaded it through my institutional account. It looks daunting! I was hoping the article was from Jearl Walker's "amateur scientist" easy-read section at the last pages of each issue. Always great reads.
Scientific American lost his footing a LONG time ago, and the demise was caused by poor selection of invitations and becoming more pseudo-technical rather than sticking to the basic sciences. There was a wonderful french magazine from the same period called Jeux et Stratégie, that suffered the same slow decline.

Drew-r

@vagfilm

In the forum editor, click the chain-link icon, insert the url with a title and optionally a description and when the post appears, the title text is the hyperlink.

Del Vento

CyberGene I believe the author of the post should be able to disable the link preview by clicking on a X button in the preview.

I don't see any X button in the preview.

Drew-r In the forum editor, click the chain-link icon, insert the url with a title and optionally a description and when the post appears, the title text is the hyperlink.

That works only if the text you specify is not the URL itself. If you specify the same URL for the text, the preview appears. I guess that's not a big deal, and I should stop being nostalgic for a gone-by text-only ASCII-art past

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