Tone production experiment

[richard black]

I'm starting a new thread for this to keep things simple to follow, but this refers to another discussion in this section on whether different approaches to the key yield different tone on a single note. The attached audio file consists of pairs of notes, one played with the stiffest arm I can manage, the other with the floppiest. The loudness of each note within a pair is very accurately matched, so any differences should be in tone only. There are ten pairs, some with floppy arm first, some with stiff first. Can you identify which is which? Please PM or email me answers rather than posting them to this thread as we want each listener to start from scratch.

This is very simple so far but if there's interest we could expand it.

Recording details if anyone's interested: Bechstein Model V grand piano in a domestic room, recorded with Royer SF-12 ribbon microphone.

[richard black]

PS - feel free to include comments with your answers too.

My email address is recordingrescue (at) gmail.com

You may need to download the file and play it off your computer's disc, rather than using the plug-in player here - it seems to stop halfway for me.

[nyiregyhazi]

I couldn't hear a notable difference through my computer speakers (presumably it doesn't matter to post that here rather than answers?). Unfortunately I don't have any headphones I can currently use to listen more closely. However, I'm not sure if I'd necessarily judge it from the floppy/stiff arm as the way to make a big difference. There's a very specific type of levering action of the finger that produces an extremely clear and "big" sound with minimal impact. Particularly with a depressed pedal, I'm confident that this can be used to make a different sound to an arm push.

[richard black]

The business of stiff or floppy arm is the most extreme difference I could think of.

[nyiregyhazi]

I think it's possible it could make a difference. However, I personally think that the biggest difference possible would be based on where the energy is sourced. Arm pressures tend to involve a lot of wastage. However, a flat fingered lever action (similar to that used by Horowitz) can coax out a big tone with virtually no feeling of a landing at all. The energy applied can feel tiny, when it's just right- with no loss of motion into slack. I want to write up my blog post on this, based on simulating actions around the knuckle with pencil. Although I already did some things with the pencil in a previous blog post, I discovered that the difference between the finger-that-supports-the-arm and the finger-that- levers-the-key can be illustrated with this as overwhelmingly significant. Basically, if you don't use the levering action from the knuckle, there's nothing the arm can do to compensate for that omission. Whether you try to apply more energy to compensate for loss into slack or try to stiffen the joints to prevent loss, it leaves a very inefficient transfer.

[john90]

It would be interesting to measure the key positions and hammer positions over time with the two approaches. I suspect that once the hammer is release from the escapement all that matters is its velocity. The instant it is released, it will stop accelerating, tone and volume will all be down to kinetic energy, ie speed, for any one note played on its own.

I suspect that the different approaches to pressing the key will result in quite different delays, if you measure the interval between key arriving at height X and string sounding. I think the tone difference, for a given note and hammer to string velocity, will be zero. Rebound should be purely determined by hammer velocity, if the string was still before impact.

I think the perceived difference in tone will come when multiple notes are played, striking a key in one way, will affect the timing and velocity of subsequent keys, and affect the energy the pianist has to continue playing. Different ways of pressing the keys allow the pianist to trade off effort and  accuracy (time and/or hammer speed).

If this is correct, all a pianist controls is the point in time a hammer hits the string, the speed it hits the string, and the point damping of the string is released before the string is struck. Tone is simply a consequence of velocity, damping and interference between notes.

Interference is very important here. The instant a key starts to be pressed, the damper for that string is raised, and the string starts to move and vibrate, in sympathy with voices in the room, doors shutting, other instruments, and other notes playing. The-pre existing movement of the string when the hammer hits it at velocity Y will influence tone (and presumably rebound) the most after velocity. The different ways of pressing the note will dramatically change the interval between key arriving at height X, and note hitting string with velocity Y, or in other words, how early the damper for that note is released for a given hammer velocity Y.

[nyiregyhazi]

If this is correct, all a pianist controls is the point in time a hammer hits the string, the speed it hits the string, and the point damping of the string is released before the string is struck. Tone is simply a consequence of velocity, damping and interference between notes.

The keybed is completely omitted from this though. It's not just what goes on inside the instrument (although, having said that, this can be carried to the soundboard). Some pianists stamp on a pedal noisily- which certainly spoils the way their tone is conveyed (or even adds a dramatic effect at times- Cziffra used to bang it at significant moments). Imagine if there were a pianist who farted very loudly as he played every note. Could anyone perceive beauty of tone quality (in his playing that is)? Also there are experiments that have shown that different rates of acceleration can change the hammer's state.

[richard black]

Also there are experiments that have shown that different rates of acceleration can change the hammer's state.

I'd be interested to see those. I've seen a few hypotheses on how that could happen, though it all sounds a bit far-fetched and deeply second- (possibly third- or fourth-) order. Can you give me a reference?

Some pianists stamp on a pedal noisily

No question at all over whether that's audible - irritates the hell out of me!

The-pre existing movement of the string when the hammer hits it at velocity Y will influence tone (and presumably rebound) the most after velocity.

I don't find that at all obvious...

The different ways of pressing the note will dramatically change the interval between key arriving at height X, and note hitting string with velocity Y, or in other words, how early the damper for that note is released for a given hammer velocity Y.

Dramatically? I can see how, in principle, it might slightly alter it - but so what? What's going to happen in the few milliseconds of undamped existence? And if the pedal's down this effect vanished completely.

[nyiregyhazi]

https://www.speech.kth.se/music/5_lectures/askenflt/pianist.html

Here's one. The fine details are over my head. However, simply knowing that it's not as clear cut that tone is impossible as is widely believed, is enough for me. To be honest, it doesn't concern me what causes the results- as long as they occur. However, I do believe it's healthier for a pianist to believe it- rather than view all absolute sounds as equal. Not that the latter necessarily makes for a pianist with a bad tone- but it's a lot easier to be slapdash about things if you don't think anything but volume matters. While many pianists who believe tone is impossible do make beautiful sounds, I suspect that many others would have been far better off if they believed it.

[keyboardclass]

Also there are experiments that have shown that different rates of acceleration can change the hammer's state.

There are none.  That's Matthay's theory.

[john90]

I don't find that at all obvious...

Dramatically? I can see how, in principle, it might slightly alter it - but so what? What's going to happen in the few milliseconds of undamped existence? And if the pedal's down this effect vanished completely.

I completely omitted the key hitting the keybed, and it bouncing back up and hitting the stop. Wessell, Nickel and Gross have this line of hammers and actions that are precisely engineered, with carbon hammer shafts, which will be a lot stiffer than wood, and more consisten weight wise, for "modding" your piano. Also the hammer pins are not running in felt bushings. I would imagine this would greatly reduce possibility for any hammer ripple effects suggested in the link  from nyiregyhazi. Would be interesting to compare tone. They claim less mechanical waste in their action allows the pianist more consistent control over the instrument.

Any pre-existing movement of the string will create a completely different sounding mechanism, something difficult to model in a computer synthesizer. It will add to the excitement compared to hammer velocity hitting a still string. Perhaps there will be more harmonics? The hammer striking a moving string cannot erase the pre existing vibrations, only dominate them unlike a damper. So this tone will be more obvious in 'beautiful' quiet passages, the lighter the touch (lower velocity of hammer), the more obvious it will be. There will be far more control of keyboard noise too. If you believe this, then a good touch is probably down to accurately controlling velocity, adapting velocity to the pre-existing resonance of the particular string, and timing damping release and keyboard noise. The bridge will still have a large effect on the string the moment the damper is released, assuming the environment is not totally silent. Bluthner add an extra string on their grands that is not struck by the hammer, to try and amplify this effect. You can try this at home, strike a damped treble note with the soft pedal down, so only two strings are struck, and manually damp 2 of the 3 strings, then the 3rd that was missed by the hammer.

You can also play one note, while holding another note down without striking the string and listen to the difference. My piano is in storage, but I'm sure I tried it and remember a difference. So pressing other notes influences tone, even before the hammer hits the string in the other notes. Even if other notes are not sounded. I wonder if any piano composers use that effect. Hmmm.

[richard black]

Thanks for the link to the Swedish article. Lots of interesting stuff there, though not many actual numbers. In addition, note the following quotes from it:

cannot rule out the possibility that the pianist's touch may have an influence on the character of the piano tone. As regards the initial "thump" it seems rather clear that it contributes to the character of the note,

 - but to what extent is not evaluated, nor is any variation with touch type investigated.

while an actual influence on the tone character via the hammer motion has not been verified yet.

- in other words it's still at the hypothesis stage.

Returning to a quote from this thread:

You can also play one note, while holding another note down without striking the string and listen to the difference. ...Even if other notes are not sounded. I wonder if any piano composers use that effect.

The best-known example is the 'Rosenkavalier Ramble' by Grainger - right at the start he uses this effect.

[richard black]

Incidentally, another source of possibly significant 'spurious' noise hasn't been mentioned yet - finger impact on the key. If you come in from a height there's quite a noisy impact between finger and key, which is very easy to demonstrate: just block a key (hold it rigid) with one hand while the other descends on it as if to play a loud note. Especially with the pedal down, this makes quite a noise. In my little experiment I deliberately avoided this as most experienced pianists take considerable trouble to play from near the keys in practically all situations, for various reasons (as diverse as accuracy and comfort).

[nyiregyhazi]

Thanks for the link to the Swedish article. Lots of interesting stuff there, though not many actual numbers. In addition, note the following quotes from it:

 - but to what extent is not evaluated, nor is any variation with touch type investigated.

- in other words it's still at the hypothesis stage.

Sure- but if you compared both sides, this would be vastly closer to a "proof" of tone than anything the other camp have ever provided to "prove" tone is impossible. Seeing as there are perfectly credible explanations of what could cause it and make it audible (that are casually omitted from explanations, in favour of obviously simplified "physics"), I think the onus is on the latter group.

The carbon shafts sound interesting. However- would they definitely restrict it to the "good" tone? What if the flexion of the hammer were useful? I'd actually imagine that this occurs the most, in the type of steadier acceleration that is usually regarded as conducive to good tone. Also, maybe it's good to use the "bad" tone in some circumstances and have the options?

[nyiregyhazi]

There are none.  That's Matthay's theory.

Eh? What are you trying to say? Matthay claimed there are no different rates of acceleration?

[richard black]

Sure- but if you compared both sides, this would be vastly closer to a "proof" of tone than anything the other camp have ever provided to "prove" tone is impossible. Seeing as there are perfectly credible explanations of what could cause it and make it audible (that are casually omitted from explanations, in favour of obviously simplified "physics"), I think the onus is on the latter group.

Very few people have ever seriously claimed that tone is actually _impossible_. Most, like me, simply question its importance, compared with the vastly greater influence of relative loudness. Obviously it's a bit of an academic exercise anyway, but an interesting one for a few nerds!

And as in hi-fi (a field about which I know far too much   ), the onus is on anyone who espouses an armchair hypothesis to back it up with experimental evidence. 'Perfectly credible' explanations are all very well but we need some actual magnitude information, a few hard facts.

For instance, this thing about hammer shanks flexing - makes sense, sure, but how _far_ is the head going to move? - and how much difference will it therefore make to the sound?

[nyiregyhazi]

Very few people have ever seriously claimed that tone is actually _impossible_. Most, like me, simply question its importance, compared with the vastly greater influence of relative loudness. Obviously it's a bit of an academic exercise anyway, but an interesting one for a few nerds!

And as in hi-fi (a field about which I know far too much   ), the onus is on anyone who espouses an armchair hypothesis to back it up with experimental evidence. 'Perfectly credible' explanations are all very well but we need some actual magnitude information, a few hard facts.

For instance, this thing about hammer shanks flexing - makes sense, sure, but how _far_ is the head going to move? - and how much difference will it therefore make to the sound?

Honestly- you hear it all the time. Tone is impossible and science says so. This is very widely believed- sometimes with a level of arrogance that treats anyone who feels otherwise as if they believe in telepathy. I've seen experiments in which people could distinguish between different qualities of tone and I can often do so myself. Try using a drop of the wrist (in which the knuckle of the finger starts high and drops in a big circle as the tip descends) to attempt a big sound. It's such a spectacularly wasteful action that the landing at the keybed is often very easy to hear. More energy reaches the keybed than the hammer.

Regarding flexion, what happens when the hammer springs back? Why would this be assumed to have literally zero effect? Again, I'd say the onus of proof is on anyone insisting that there is no way this could ever make an audible difference.

[richard black]

More energy reaches the keybed than the hammer.

This is literally true under most circumstances, I believe. But so what? In detail and in cases of different 'approach' to the key, so what? How are we going to demonstrate this experimentally? Supposing you and I met in a room with a piano and some recording equipment - could you demonstrate these differences so that I can record them and put them on this (or some) website?

[keyboardclass]

More energy reaches the keybed than the hammer.

That's called keybedding and is bad practice.  Hummel said you could do it on Viennese action pianos (5mm key dip) but not English pianos (7mm keydip).

[richard black]

You simply can't avoid the key hitting the bottom, though you can vary how hard (to be precise: with how much momentum, including that of the finger/hand/arm) it hits. However, if you do simple Newtonian maths on the weights and velocities involved you'll find that just about the best imaginable case has roughly equal kinetic energy going into hammer and keybed.

[keyboardclass]

You simply can't avoid the key hitting the bottom, though you can vary how hard (to be precise: with how much momentum, including that of the finger/hand/arm) it hits. However, if you do simple Newtonian maths on the weights and velocities involved you'll find that just about the best imaginable case has roughly equal kinetic energy going into hammer and keybed.

I think acquiring the appropriate reflex action gets rid of a lot of keybedding.

[richard black]

You can reflex all you like, but in general if the key is going down fast enough to launch the hammer, the key is going to travel a further couple of mm (what's to stop it?) and hit the bed. Not necessarily hard, but hit it nonetheless. It's true it doesn't feel as if it's getting down there but I'd wager it is, at any dynamic above pp. The important thing would be just how hard it hits, and even if someone does prove that the difference between hard and marginal keybedding is not audible, there's still no argument I can see in favour of it - it simply wears out players and pianos faster!

[nyiregyhazi]

I wrote most of a blog post about exactly this a couple of nights ago. Just got some exercises to add. Preventing contact with the keybed is absolutely impossible- beyond all doubt. What IS possible is to either redirect momentum after the landing, and to alter how much momentum is involved. Arm pressures involve more loss of energy in moving the key- but pile on much more momentum at the keybed. finger actions (when done efficiently) can be directed to avoid a face-on impact with the keybed and carry relatively low momentum. When done well there is no urgent need to relax- because there's no jamming in even if you continue the action. In this action, the arm is not piling in from behind like a train crash. Other actions hit the keybed hard and cause strain unless immediately stopped (which is impossible- hence it's damage limitation at best). I'll give a practical illustration of what makes low impact action possible in the post, within a few days. The principle is very simple.

[nyiregyhazi]

This is literally true under most circumstances, I believe. But so what? In detail and in cases of different 'approach' to the key, so what? How are we going to demonstrate this experimentally? Supposing you and I met in a room with a piano and some recording equipment - could you demonstrate these differences so that I can record them and put them on this (or some) website?

Fair point. To be clear- what I should have said was that vastly more energy goes to the keybed than hammer in the action described, when compared to normal. The ratio leans hugely towards keybed rather than hammer here. With this inert wrist flopping action (the single most inefficient I've been able to find and not one I would use in any practical scenario) I'm 100% sure it can be heard. The tone produced is very small and the thump of the key is easily audible. 

[john90]

How are we going to demonstrate this experimentally? Supposing you and I met in a room with a piano and some recording equipment - could you demonstrate these differences so that I can record them and put them on this (or some) website?

I think so. A computer screen with some sound editing software might be the most clear way on a web page.

https://www.speech.kth.se/music/5_lectures/askenflt/hammres.html

https://www.speech.kth.se/music/5_lectures/askenflt/coda.html

Discussion of key bottoming, and how this varies in relation to point of hammer string contact times:
https://www.speech.kth.se/music/5_lectures/askenflt/keybott.html


Finally this last link seems to offer proof of the existence of tone control by the pianist, second to last paragraph. The hammer velocity stays the same, but different motion of the hammer is caused, even when end velocity is the same. Backwash and Ripple, according to the article. These vary according to the touch used. The pianist noted a large variation in tone produced. The testers said the difference was only subtle.

https://www.speech.kth.se/music/5_lectures/askenflt/motions.html#hammermotion

[richard black]

john90 - thanks for that, useful links. I think you misunderstood me about 'putting it on the website' though: I meant that I could put the recordings on here, as at the start of this thread, so people could listen 'blind' (i.e. not knowing which case was which) and draw their own conclusions about audibility of tone-influencing factors.

[pianowolfi]

Of course there are zillions of discussions going on about tone, beauty of tone versus physical approach i.e. just the volume of tone can be influenced by the player.

I think what we recieve as quality of tone and individual difference of tone is fairly psychological to a significant extent. So it might be only measureable by psychological methods of measurement and not by physical methods. Does that mean any difference is inexistent? In my opinion no.

Example: take this recording of ten pairs of notes just as a musical listening experience, of course including the commenting voice in between the pairs. Isn't this a work of art in itself?

[richard black]

Thanks to the people who listened to the track and commented - not many so far! Anyone else prepared to spend a couple of minutes on it?

Many thanks in advance.

[bbush]

Thanks for the effort, Richard!  But I, too, did not hear any significant differences in your 10 passes at the same note, evidently with you utilizing 10 different approaches/ways of striking the key.

Since I kinda-sorta started this round of discussion with your reaction to my comments to Mike1127 on his thread: https://www.pianostreet.com/smf/index.php?topic=41041.0 I certainly appreciate your taking this issue of tone production seriously and attempting to get at some unquestionable data.  As others have written, there IS (in our experience) a significant difference in tone production possible, but without being at the piano with someone right there listening, I'm afraid I can't describe a way to prove it to you; it evidently must be demonstrated... and perhaps it would take a much more controlled pianist than I to do so effectively, that is, to your satisfaction.

Yours,
Bruce

[richard black]

Seems about time to pass on the results - no listener (out of 5 who responded - thanks to you all) could hear consistent differences. Obviously it's a simple and rather crude test but capable of refinement without too much trouble. The methodology is broadly similar to that used in lots of audio experiments (for example, to check for the audibility of certain kinds of signal processing) though even that could probably be slightly improved, and of course more trials would be a good thing (about 20 would be ideal).

Ideally two pianists would be involved, with different techniques - and indeed I can think of one or two people I could ask. Also, ideally, I would use a newer piano than my dear old Bechstein: it makes a bit of noise as you release the key which is something you don't get on newer instruments and so not a valid part of the test, but it does give some clues as to the way a key has been pressed down. I may yet get round to something more sophisticated, but I feel even this simple experiment suggests that tone of individual notes isn't something blindingly obvious. Tone of multiple notes is something completely other.