Topic: Could the duplex scale be modeled differently ?

I have been going back for a change to my sampled piano after a long time exclusively with pianoteq, and as this posted comparison suggested ( http://www.forum-pianoteq.com/uploads.p...einway.mp3 ) I got again well aware of the differences in the attack quality. In fact, cutting away the first 50-60 ms of sound from a sampled piano, and comparing it with pianoteq, it gets harder to say which is which as this example shows ( http://www.forum-pianoteq.com/uploads.p...e_fade.mp3 ) even though here, I just played the top notes in pianoteq.

There are two things missing in my opinion, a modelling of the very subtle hammer/string interaction that varies a lot with velocity (may be very hard to do in real-time) and better duplex scale, which we very well hear in the hammer_test_ivory example and also in the Andras Schiff example given below.

I have been reading a bit about duplex scale, and I don't think the current implementation in pianoteq does justice to the effect needed. The one we have sounds a bit like out-of-control spring reverb if we push it too much, and also recalls a glass organ to my ears. It seems to resonate a lot on C5 and be confined mostly to the two upper octaves (without dampers). The Schiff example shows a sympathetic resonance centered around E4.

Also our version sounds a lot inharmonic to me while for instance wikipedia says : "...each note of the duplex scale ideally bears a perfect harmonic, intervallic relationship to its speaking length, i.e., a fifth, octave, twelfth, double-octave, etc"

I would like to suggest a different approach to modelling this effect which may be easier to accomplish than the hammer-string interaction. I got this idea when listening to this example
( http://www.forum-pianoteq.com/uploads.p...onance.mp3 ) taken from Andras Schiff's Beethoven conferences.

The resonance sound of the 2nd note reminded me of a sound effect from a Korg M1, an ancient synthesizer I used to own, one of the first one to use recorded samples. This effect was recorded from a bathroom pole, hit and dragged somewhat, don't ask me what it was used for, I have no idea...probably just for fun and also to fill unused synth memory (even if they had so little of it...)

Here is the bit of the sound that I found interesting to explore
( http://www.forum-pianoteq.com/uploads.php?file=pole.mp3 ) and here it is transposed higher ( http://www.forum-pianoteq.com/uploads.p...transp.mp3 )

To me it sounds a lot like the resonance in the Schiff example. So I recorded in pianoteq the upper notes of the example
( http://www.forum-pianoteq.com/uploads.p...source.mp3 ) and added this "pole" sound to it giving this ( http://www.forum-pianoteq.com/uploads.p...result.mp3 ).

Now I know this may sound to some like simply adding a tambourine sound to the piano, but the added sound I got is not tuned properly as it should, the purpose of this is only to suggest that maybe modelling an empty metallic pole resonating (like an organ pipe) may be a way to get this effect. Since the duplex scale originates from loose piano strings, an empty metal pole just might be a good model for it. Don't ask me for the equations needed to model this though...but maybe Philippe knows.

Maybe a quick and dirty way would be to add this properly tuned sound varying with velocity and keyboard position in the same way the hammer sound is done. Another parameter that we could control note by note in the Pro version...or turn off if we don't like it.

Re: Could the duplex scale be modeled differently ?

Gilles wrote:

Also our version sounds a lot inharmonic to me while for instance wikipedia says : "...each note of the duplex scale ideally bears a perfect harmonic, intervallic relationship to its speaking length, i.e., a fifth, octave, twelfth, double-octave, etc"

Gilles, that does not mean that the duplex scale has no iH: in fact, being built from the same strings as the notes that are stroked, being shorter for most of them because intended to produce a higher pitch above the related note, and having (approximately) the same tension as the related note, the duplex scale has a higher iH than the part of the string which is stroked by the hammers. I say ‘approximately’ because due to the friction at the bridge, the tension seldom equilibrates and there can be quite a big gap between the theoretical values and the real values of the fundamental frequencies of the duplex scale. The usual difference between theory and practice…

Concerning range, it is in Pianoteq the same as in acoustic grands equipped with duplex scales, that is fundamentals pitch starting more or less one octave below the last damped note pitch, which has in the real world the advantage of producing a smoother (although imperfect) transition between damped and undamped notes.

Re: Could the duplex scale be modeled differently ?

Gilles,

About your second point: would it help if we could tune the Duplex scale? A big feature addition, since it would have to be note-by note. But it may be what you are suggesting. Not so much a change in the model as this one control? It would give you the ability to change the relationship of the partials to the partials of the main string and the unisons and thus how everything beats. That would control the glassiness or springiness, etc?

The new K1 sounds very, very good. I'm still exploring all of its possibilities. At the same time, I've also wanted to post something else about what I think is a combination of this duplex sound, the direct sound, and the soundboard sound.

Now, to me, each note seems to move in a steady progression from the strings to the soundboard. But when I listen to recordings, I sometimes hear two very distinct sounds that occur at the same time: One is a more rounded sound, and the other is a more crisp sound. They overlap for a time, and then the rounded sound fades, leaving the more crisp sound to fade. I'm not sure what "sound sources" contribute to each distinct sound. I suspect that the duplex strings contribute most to the initial rounded sound, since I think their purpose is to make the piano sing a bit more.

I also want these two sounds to occupy more distinct places in the vertical spread--the rounded sound usually seems to be a little higher, and the crisp decay to come from lower down, perhaps fading towards the rear of the piano from the player's perspective. In fact, it may be the vertical separation of the sounds that I need the most--the two distinct sounds may be there, but I because they come from the same place, they get combined.

But I'm not really sure if all of this is related to the duplex or not. So don't let me hijack your thread. I can move off onto another thread if what I'm describing is something else altogether.

Last edited by Jake Johnson (28-03-2010 20:09)

Re: Could the duplex scale be modeled differently ?

Jake Johnson wrote:

About your second point: would it help if we could tune the Duplex scale? A big feature addition, since it would have to be note-by note. But it may be what you are suggesting. Not so much a change in the model as this one control? It would give you the ability to change the relationship of the partials to the partials of the main string and the unisons and thus how everything beats. That would control the glassiness or springiness, etc?

Doubleclicking the Duplex Scale slider currently opens the same NE window as Sympathetic Resonance. So, this could be done easily in PRO, just adding Duplex Scale Pitch on doubleclick of Duplex Scale fader!

Hard work and guts!

Re: Could the duplex scale be modeled differently ?

I hope my post was not taken as a criticism of the new K1 which I like a lot.

I just wanted to point towards future enhancements in the model.

Maybe what I hear is more related to duplex scale implemented with tunable aliquots as in this Fazioli tuning example:

www.youtube.com/watch?v=WRmk36hf40c

The sound I hear may indeed resemble more a resonating piece of metal instead of strings, but it is quite apparent in real recordings.

I used this doctored fxp ( http://www.forum-pianoteq.com/uploads.p...uplex).fxp ) to investigate pianoteq's duplex scale, which may make my comments clearer.

EDIT: The term aliquot is used differently in many instances. I thought it represented the metal bar around which a 4th string was looped, and that could resonate with the unstruck string, but I may be wrong...This is a bit confusing for me, not having access to a real grand piano myself.

Last edited by Gilles (28-03-2010 20:57)

Re: Could the duplex scale be modeled differently ?

Well, is he tuning the duplex in that video? Seems to be raising the pitch back there, but I'm not sure what he's hitting.

Last edited by Jake Johnson (28-03-2010 21:02)

Re: Could the duplex scale be modeled differently ?

Jake Johnson wrote:

Well, is he tuning the duplex in that video? Seems to be raising the pitch back there, but I'm not sure what he's hitting.

Yes I think so. This is probably what is called a "rear duplex" where the unstruck strings are attached to the metal frame separately.

EDIT: couple of informative pictures down here :
http://www.pianoworld.com/forum/ubbthre...d/1#import

Last edited by Gilles (28-03-2010 21:07)

Re: Could the duplex scale be modeled differently ?

Gilles, nothing wrong with your post, it is a very interesting subject to discuss

I tested your fxp but I would say that it is not appropriate for investigating the duplex scale, because the changes that you made modify both the duplex scale and the sound that "feeds" it, and thus you are not hearing anymore the duplex scale of a piano but the one of a virtual instrument that has no equivalent in the real world. For example you should not reduce the impedance, because it acts on the duplex scale! (the duplex scale strings being connected to the soundboard through the bridge, it inherits the soundboard impedance).

I think the best you can do for investigating the Pianoteq duplex scale is to push the sympathetic resonance to the left (that will leave only those resonances from the duplex scale) and the duplex scale slider to the right (as you did), disable the reverb, and… that’s almost all you can do without altering the duplex scale, and that will give you the best picture of the duplex scale sound in it's 'normal' state.

Re: Could the duplex scale be modeled differently ?

Coincidentally, the recordings I posted of the EBVT + Stopper 12ths may illustrate part of what we are talking about--at least part of what I mean: the longer, wirey sustain sound comes from a slightly lower place in the vertical sound stage. Possibly the early sound is the sound near the underside of the lid, or the sound as it moves back and forth between the lid and the soundboard, and the later wirey sound of the late decay is more the sound of the soundboard? (The main mic in the recording is under the hood.) The latter, late decay sound is lower in volume, so it's not being reflected off of the lid as much, and is more localized below the player?

Again, I don't know if this is related to the duplex scale: I'm not sure how the duplex sound contributes to the direct sound and to the soundboard sound, and to the decay stages. To all of them, of course, but I'm not sure if in equal quantities or how the sound localization for it works out.

Last edited by Jake Johnson (28-03-2010 21:16)

Re: Could the duplex scale be modeled differently ?

Philippe Guillaume wrote:

I think the best you can do for investigating the Pianoteq duplex scale is to push the sympathetic resonance to the left (that will leave only those resonances from the duplex scale) and the duplex scale slider to the right (as you did), disable the reverb, and… that’s almost all you can do without altering the duplex scale, and that will give you the best picture of the duplex scale sound in it's 'normal' state.

Oh I see, then I get the sort of "springy" or "tremolo-like" reverb that is emphasized with only these two changes. But then what is the more precise metallic resonance I hear on Schiff's record and also using samples? It doesn't sound like that at all...is it something else than the duplex scale or simply a loose bolt somewhere?

Re: Could the duplex scale be modeled differently ?

Could it be due to the recording technique? One can get very different sounds when changing the recording devices and settings. Another thing that I am wondering concerns the effect of the hiss present in audio recordings, could it be possible that it emphasizes high frequencies? Strangely, among the many customers requirements, nobody yet has asked for adding hiss

Re: Could the duplex scale be modeled differently ?

Philippe Guillaume wrote:

Could it be due to the recording technique? One can get very different sounds when changing the recording devices and settings. Another thing that I am wondering concerns the effect of the hiss present in audio recordings, could it be possible that it emphasizes high frequencies? Strangely, among the many customers requirements, nobody yet has asked for adding hiss

No! Please, no hiss!!! There is some in the Schiff recordings probably  because they are from a series of radio broadcast conferences transcribed to 128kbps mp3. Maybe the metallic sound is the sound technician accidentally hitting the microphone pole...

But seriously it is there on every E4 hit hard enough or around this area and less present on other frequencies, and also on my Sampletekk Black Grand and on the mentioned hammer demo for Ivory Steinway , so it must be purposeful, but what is it if it's not the duplex scale?

EDIT: Here is a small example using the Sampletekk Black Grand. Less apparent than the Ivory Steinway, but then it's "only" 6 Gigs...

http://www.forum-pianoteq.com/uploads.p...duplex.mp3

(Did this a bit fast...it's a 48kHz mp3 that may not work with all soundcards)

Last edited by Gilles (28-03-2010 22:45)