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acoustic piano - just how much control do we have?


Dave Horne

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I jumped into a thread in another forum and commented that anyone pressing a key (striking, hitting, pressing, jumping on, etc.) with the force of say, 350 grams, will result in the same exact sound. Some people seem to think that there's more in play than just the downward force of the key which then translates into the hammer velocity.

 

I contend that a force of say, 350 grams, impacting a key (regardless of the source) will generate the same hammer velocity which will then generate the same sound. I also contend that the vast supposed differences that some claim to hear emanating from the same piano is really just the amount of control (or lack of) the various performers have.

 

Any takers? Is there more than just the hammer velocity we can accurately measure? Any physicists here who play piano?

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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I also posted the following message at http://www.physlink.com

 

Hi, I am not a physicist and submitted a question here to help settle a discussion. I am a professional pianist and for me, at least, the 'sound' of a particular note on a particular piano is solely dependant on the velocity and mass of the hammer, period.

 

There are some people (not I) who believe there is more than just the velocity of the hammer involved. There are some who believe that striking a key on the piano keyboard from a distance of, say, 30 cm, will result in a different 'sound' than if you applied the same force (same exact hammer velocity) from a distance of say 20 cm.

 

For me (and I hope you as well), the strings only 'see' the impact of the hammer and it does not matter how that velocity was achieved. If the velocity of an attack was the same whether I used my elbow, my nose or my fingers, the resultant sound would be the same.

 

Is that essentially correct? (Bear in mind I am a professional musician and nothing more.)

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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From a strictly mechanical standpoint, principles of conservation say that in theory you are correct. Provided, that is, your start point is identical each time AND the mass of the striker is identical each time.

 

Here's how it works: A 350gm object dropped from 1 micrometer will hit the string with a force of 350gm. So will a 10gm object of similar composition striking from a height of (guessing here) say, one meter. Can you expect them both to sound alike? No. All the other issues - damping due to lack of bounce, sharpness because the lighter object deflects more easily, the possibility of the string already being in motion due to other forces - all will affect the sound. They will not affect the total energy of the system, but they will affect the way that energy is redistributed.

I used to think I was Libertarian. Until I saw their platform; now I know I'm no more Libertarian than I am RepubliCrat or neoCON or Liberal or Socialist.

 

This ain't no track meet; this is football.

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I guess maybe you'd always get the same initial sound (however that is defined), but how the weight settles down on the key impacts the overall sound of the note to its completion, obviously. Since a piano is a percussive but also in some ways a singing instrument, a lot happens with a note after the initial hit of the string. This isn't really substantive but probably just a clarification of language.

 

Separately, when playing very quietly, I feel as though I can excert control by how I accelerate or decelerate. For example going very slow for part of the way then speeding up at the end. Now, yes, this could be done with the nose or whatever, but not with dropping a weight.

 

Lastly, we like to believe our art is more mysterious than it is. Maybe everything can be analyzed down to Physics but that's no fun for artists!

 

Chaso

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Originally posted by Chaso DeChaso:

 

Lastly, we like to believe our art is more mysterious than it is. Maybe everything can be analyzed down to Physics but that's no fun for artists!

 

Chaso

have to hook in here, as some one who study phisics. It is great to analyse how exactly things works, that does not mean it loses something of its mysteries.

 

as I see it, there are three things that could affect the sound of a piano strike.

 

1) the force on the key

 

2) the velocity with wich you strike a key

 

3) the amount of time you hit the key.

 

don't think other things could effect the sound. I am not talking about droping weights from a meter here, because if you do that, as coyote say, the thing will bounce in a different way, and so less enery goes to pressing the key.

Rudy

 

 

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I know there have been lengthy articles written about this (and my eyes have glazed over reading them), but _does_ it matter if a lead ball is dropped on the key instead of the same force applied by my ... elbow?

 

The string only 'sees' the impact of the hammer as it strikes the string. Is that not correct? It doesn't matter to the string what the acceleration of the hammer was prior to impact, it is just the impact that the string sees .... or not?

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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It totally depends on the hammer's velocity when it leaves the wippen. It doesn't matter where the keystroke starts. You could pause half way down if you wanted. If you get the hammer up to the same velocity, it will sound the same.
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The hammer shank will bend or flex depending on the velocity of the keystroke.

This will change the way the hammer transfers energy into the string and therefore change the relationship between fundamental and the partial of the note.

 

If the velocity changes during the keystroke then the tone will change as well.

 

We must also understand the state of the hammers in question as well. If there is considerable compression under the strike point but much less around the top of the shoulders then the sound could be dramatically different

Peace

 

 

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"Once again: The perception of piano touch and tone. Can touch audibly change piano sound independently of intensity?"

 

Werner Goebl, Roberto Bresin, Alexander Galembo

 

http://www.oefai.at/cgi-bin/get-tr?paper=oefai-tr-2004-02.pdf

 

"This study addresses the old question of whether the timbre of isolated piano tones can be audibly varied inde-pendently of their hammer velocities only through the type of touch. A large amount of single piano tones were played with two prototypical types of touch: depressing the keys with the finger initially resting on the key surface (pressed), and hitting the keys from a certain distance above (struck). Musicians were asked to identify the type of touch of the recorded samples, in a first block with all attack noises before the tone onsets included, in a second block without them. Half of the listeners could correctly identify significantly more tones than chance in the first block (up to 86% accuracy), but no one in block 2. Those

who heard no difference tended to give struck ratings for louder tones in both blocks.

 

1. Introduction For almost a century, physicists and musicians have been arguing whether it is only the final hammer velocity that determines the sound of a piano tone or whether a pianist can additionally influence the piano timbre by varying the way of touching the keys. Pianists study for many years extremely intensively to advance their technique of touching the keys so that the outcoming sound satisfies their (and their teachers) high artistic demands. They es-tablish and refine various kinds of accelerating the keys in order to obtain finest timbral shades so that it might be hard for them to believe that piano timbre might be ex-pressed by a single physical parameter. The physicist, on the other hand, argues that the pianist loses control over

the hammer after the jack is escaped by the let-off button. Therefore, it is only the endmost velocity of the hammer that determines the intensity and thus the timbre of the piano tone.

 

The two positions are apparently contradictory, but they are not necessarily. A pianist manipulates naturally all expressive parameters simultaneously when playing a piano, so there might be audible differences in sound when two tones are played with different types of touch.

However, it is very likely that in such an uncontrolled case, more parameters than only final hammer velocity have been varied. For scientific investigation, we have to reduce the problem to its very essence: Is it possible to produce two isolated piano tones without using the pedal with identical final hammer velocities, but with audibly different sounds? Apart from historic studies starting from the 1920s [1, 2, 3, 4, 5, 6, 7], the more recent literature found dif-ferent kinds of noise that emerge when the key is struck in different ways [8, 9, 10]. The most prominent noise emerges when the hammer hits the strings (hammer string noise, attack thumb [8]). This noise characterises the specific sound of the piano, is most prominently au-dible in the treble strings, but cannot be varied with type of touch independently of hammer velocity. When a key was hit from a certain distance above, a characteristic fingerkey noise was found to occur 2030 ms before the actual tone (touch precursor [8], early noise [9]). This noise was clearly visible in au-dio wave form plots. Although the authors reported that listeners could easily distinguish between tones that were

played from above and those played from the keys, no systematic listening test was reported [9].

Although measurement tools improved since the first systematic investigations in the 1920s, no more conclusive results could be obtained as to whether the touch-variant noise components (especially fingerkey noise) can be aurally perceived by listeners not simultaneously involved in tone production. This study investigates whether musically trained participants in a controlled ex-perimental situation are able to distinguish between dif-ferent types of touch, even if the fingerkey noises are removed."

 

...the study continues at:

http://www.oefai.at/cgi-bin/get-tr?paper=oefai-tr-2004-02.pdf

 

(conclusion in next post)

Harry Likas was the Technical Editor of Mark Levine's "The Jazz Theory Book" and also helped develop "The Jazz Piano Book." Harry spends his time teaching jazz piano online and playing solo piano gigs.

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http://www.oefai.at/cgi-bin/get-tr?paper=oefai-tr-2004-02.pdf

 

4. Conclusion

"This study confirms that the difference between two equally loud piano tones due to type of touch lies in the different noise components involved in the keystroke [8, 9]. These noise components (i.e. fingerkey noise) are audible when the key is struck, and absent when it is pressed down. This study provides a first systematic perceptual evaluation of whether musicians can aurally identify the type of touch that produced an isolated piano tone, independently of hammer velocity. Our results suggest that only some musicians are able to distinguish between a struck and a pressed touch using the touch noises as cue, especially the fingerkey noise that char-acterises a struck attack, whereas others could not tell any difference. Without those touch noises none of them could tell a difference anymore. When they could not hear the touch differences, they tend to rate louder tones as being struck, and soft tones as being pressed. We can only speculate about how the present findings generalise to a real-world concert situation including pedals, rever-beration, reflections, and the listener at a certain distance away from the piano). In the light of the present results,

we consider the pure aural effect of touch noises (exclud-ing visual and other cues) a rather small one."

Harry Likas was the Technical Editor of Mark Levine's "The Jazz Theory Book" and also helped develop "The Jazz Piano Book." Harry spends his time teaching jazz piano online and playing solo piano gigs.

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Thanks! There will be a quiz in ten minutes, please put your books under your chair.

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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Jazz+, I'm reading that paper you partially quoted from. This is interesting stuff.

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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I apologize for my empyrical approach, but I wish to say a few words in favor of the possibility for the pianist to have, so to speak, a 'personalized' touch on the instrument.

 

First, I absolutely agree with the statement that the velocity 'at the moment of impact' between the key lever and the hammer mechanism, is really the only thing the piano needs to see in order to create the timbre of a single note. There's nothing a pianist could do to alter that, no matter how many contorsion he tries. Sometimes the escapement mechanism gets in the way, but getting around this is the pianist's problem, not the piano's. :)

 

On the other hand, every good pianist knows, sometimes not totally consciously, how to alter that initial timbre using a series of tricks:

 

- Pedals

- Articulation

- Release

 

With the pedal, you can hear the effect even on single notes. For expressive melodies, play the note, then push the right pedal down *progressively*. You can do that for every imortant note of your melody, no matter how soft or loud. It gives the note a kind of swell, more subtle and mysterious than on a wind instrument, but definitely audible.

For soft, carillon-like textures, use both pedals together, *partially* raising the right pedal at strategic points.

Different effects can be obtained by depressing the key *and* the (right) pedal at the same time, by letting go the pedal a little bit at a time during a melodic passage, by using a constant, *partially* pressed pedal for a given passage, etc. etc... ;)

 

Articulation is the relation among notes, and between notes and time. It involves at exactly what time you let go one key with relation to the ones which are still depressed, the relation of dynamics between notes in a chord or a fast passage, the various degrees of legato from letting melody notes overlap to playing them non-legato, the accentuation of strategic notes and their relation to the non-accented ones, and several other aspect of practical playing.

 

The importance of the way the pianist release the key has been overemphasized a bit in recent times perhaps, but it's indeed very important, especially for slow, expressive melodies. The difference involves the noise from the dampers, and especially how each melody note 'shifts' to the next one.

 

I only scratched the surface on the problems of piano touch - my purpose was just to reaffirm that there *is* a piano touch! :D It is just a bit less related to the matter of the initial keystroke than one would think, and more to the relation between that and the other things I mentioned.

A pianist knows how to obtain the psychological effect he wants, by combining all these elements.

 

Needless to say, fery few of those aspects are reproduced on any digital piano... :rolleyes:

 

Carlo

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And another related point to articulation is that, in practice, it is easy to tell the difference between "struck" and "press" because, in practice, one isn't playing just one note, but several in succession. In order to "strike" several notes in succession you need to lift your finger off the keys more quickly than when you're "pressing" several notes in succession, assuming you're playing at the same tempo at least moderately fast. This quicker release should be noticeable even though there is no difference in hammer strike.
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Another aspect of the question involves the transition from piano to MIDI controller.

 

If it were true that only the final velocity determines the timbre, then a midi controller should be able to be just as expressive as a piano, assuming the controller has sufficient (and proper) sensitivity to the touch (perhaps 1023 levels rather than 127.) But as any electronic keyboardist can testify, this is NOT the case.

 

A large part of the problem is the way velocity is identified on the midi controller, typically it's the time from key up (beginning) to key down (ending), whereas on a piano this pressure gradient can take many shapes - lightly but quickly can produce a soft, delicate tone on a piano, but on a midi controller it will be loud. Slowly, but with intensity will be louder on piano than controller. Etc.

 

So the real answer may be - it doesn't matter, the artist creates his/her own response/pressure gradients that assist in identifying the style, even on classical songs where the same notes exactly are played by different players, yet you can tell Glenn Gould from Van Cliburn.

 

And what needs to be studied is these pressure curves from different artists, with an eye toward developing a properly responsive midi keyboard; this could be done in a way to make the result be indistinguishable from real (or at least a lot closer.)

 

Ultimately, a hammer/escapement action that simuated a piano, with sensor struck and actual force measured at that endpoint would produce the true acoustic 'feel' (keyboard sensation plus percieved audible result) in an electronic instrument. Measuring the time from key up to key down just doesn't work...

 

If you feel this is OT, just ignore the post. :rolleyes:

 

Dasher

It's all about the music. Really. I just keep telling myself that...

The Soundsmith

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I really doubt their identification of that early sound as "finger noise". Especially when they recorded so close to the string (although some of it is undoubtably mechanism noise)

 

It looks like a component of that "touch noise" is the string vibrating as a result of the damper lifting. Its hard to tell but there appears to be a harmonic content in there, not just noise. Clearly striking the key will cause higher frequency components to that than lifting slowly. These will couple better to a close mic and the air - as these are fast the sounding board has little time to enter into the equation in any case.

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2 thoughts

 

The "finger noise" would appear to actually be the beginning of a sympathetic resonance that occurs from the time the key (and thus the instrument) is struck. This could possibly act to excite a pre-vibration in the keys prior to the hammer strike, causing a harmonic wave that amplifies or colors the actual post-strike sound. Much in the same way as a ride cymbal acts.

 

Secondly, I feel that there is actually an oversimplification going on over the elastic transfer of energy from the hammer to the string. First you have Velocity, which has been addressed. Then you have to deal with Hammer Force whis is only partially related to final velocity. Hammer Force is related to ACCELLERATION up to the point of impact and Decelleration after release. IIRC there are formulas to deal with accelleration and decelleration continuiong through the point of impact in a flexible system ie not hitting a nonmoveable or static object(but its been over 10 years since my last physics class) since the point of impact and the point at which the potential energy is completely absorbed by the pad and string. Lastly there is the factor of time (call it Release Latency) Release latency would describe the time between initial impact and removal of contact(we're dealing with a system where there is the possibility of the hammer being removed from the string before all of the energy is transferred or after energy has been re-absorbed by the pad)

 

Without giving myself a calculus headache or writing a doctoral thesis, yes, Dave we do have an immense control over the instrument. ;)

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Without giving myself a calculus headache or writing a doctoral thesis, yes, Dave we do have an immense control over the instrument.

The initial reason I pursued this, someone (in another forum) suggested that the sound of a piano was 'different' depending on the player. He wasn't just talking about different articulations and dynamic levels, he believed the sound of the piano, the intrinsic sound of the piano, varied with the performer. I disagreed with that.

 

I read the study that was previously mentioned here and that 'pre -noise' (finger - key noise) ... the additional noise that occurs when striking the piano key from a distance, is either there or it isn't - it can not be controlled, per se.

 

The study in its Introduction asks, 'Is it possible to produce two isolated piano tones without using the pedal with identical final hammer velocities, but with audibly different sounds?'

 

The short answer is, yes, but the difference was only the hammer strike noise which can not be varied independently of the hammer velocity. It's also worth mentioning that the microphone was placed 10 cm away from the strings; our ears are never that close to the strings. In the real world, we, as the audience, would be meters or tens of meters away from the strings. For some this can be a religious discussion, they will believe what they believe regardless what the studies show.

 

For me it all gets down to how much control the performer possesses. When I'm on stage I might add a few extra visuals to my playing (hands flying around, head moving) and if that influences someone to hear something extra, I'll take the credit and won't destroy their illusion.

 

A shitty piano is still a shitty piano. A performer with better control can make the piano sound better than someone with less control.

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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In light of your last post, Dave. I would have to consider The other person's initial arguement flawed or at least too oversimplified to make an accurate judgement.

 

The elusive answer to the question of a particular instrument's intrinsic "sound" versus the "sound" a skilled player is able to coax from even crappy instruments lies at the heart of most arguments and is the source of most 'musical snobbery' on the playing side and the listening side of the issue. With acoustics being so complicated and easily influenced and the totally subjective nature in which our ears/brain decode the audio stimulus how can we be sure that we are not all just full of bunk?

 

All I can say is I have witnessed someone play an acoustic instrument (in this case a cello) theis person was such and excellent player that the limitations of the "collegiate" level of instrument became aparrent. You could actually hear the instrument fail to reproduce the tones. It was similar to listening a speaker or amp fail to reproduce a frequency range well. Not clipped, just lacking in tonal quality that existed just a note before.

 

I also feel that any attempt to base the study of a sound like this one just one key press is a flawed excercise. there is too much intterplay inside the piano and at the players fingertips when an instrument is played to be simulated by one key press.

 

Maybe it would be better stated this way: The sound of an instrument is independant of the way its played, however the dynamics color and tonal qualities of the sound of the instrument will vary greatly dependant upon the player.

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OK, this seems to be settled, now we can get on to the eternal question of how many angels can dance on the head of a pin block.

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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Originally posted by Dave Horne:

OK, this seems to be settled, now we can get on to the eternal question of how many angels can dance on the head of a pin block.

Not quite, the next question should be "What sex are angels, anyway?"

This question fuelled many a vigorous debate during the middle ages. (and prompted many accusations of heresy)

Nowadays of course, most people would say female, and that is the PC answer. But back then, the orthodox view was that all the angels were male.

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... but the size, not the sex of the angels, would be the determining factor, n'est pas?

No guitarists were harmed during the making of this message.

 

In general, harmonic complexity is inversely proportional to the ratio between chording and non-chording instruments.

 

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Presumably, the sex would determine the size of the angels, no?

 

If males are bigger than females, then fewer male angels will be able to dance on the head of a pin, than if they were females.

The other factor is that males don't generally prefer to dance together unless there are females present. Females will dance even by themselves with no male present. :D

 

So... if angels are male, then only one can dance on the head of a pin. If they are female, then more than one (the exact number is up for debate) can fit. :cool:

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You can worry too much about the particulars and end up taking steps backwards.

 

I went to a music school and one of the teachers was a Madame Chaloff. Madame Chaloff has gotten great notices from the likes of Chick Corea and had quite a reputation. I was friends with many of her students at this university. Every student of hers played worse than when they started fas a result of her pedagogy, although they all loveed her; which from my outside observation and conversations with her students seemed to be concentrated on the tone of any one particular note.

 

I think for acoustic piano, slow practice to master how you want to play difficult passages, and an absolute understanding of what you are doing theoretically, are the precursors to then playing from what you imagine you would like to hear.

 

For some reason I believe that your musical imagination can demand from your fingers the tone you want without the interference of thinking about velocity or distance from striking the key and other highly mechanical aspects of piano technique analysis.

 

I've observed many piano players and I've observed no consistency in piano technique that gets fabulous results. Seems to me that since the physiology of people's hands and arms differs, the pianist has the unique problem of discovering what works for him. Of course, reducing unneeded tension is important, but the manner of holding the hands, height of the bench and other things can vary as suits the need of the individual pianist.

 

There's more than one right way of doing things.

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Originally posted by Dave Horne:

The initial reason I pursued this, someone (in another forum) suggested that the sound of a piano was 'different' depending on the player. He wasn't just talking about different articulations and dynamic levels, he believed the sound of the piano, the intrinsic sound of the piano, varied with the performer. I disagreed with that.

Sure, the affirmation that the pure, initial sound of a piano could change with touch at the same velocity is a naive one, but maybe trying to confute it with a single note evidence is even more naive. Most of the breath of piano playing is in the interacting among its plethora of strings, and that's where the pianist's control reside. I've heard several different classical pianists playing the same piano, and making it sound like a different instrument every time (and no, most didn't have the time to regulate it to their liking). If you could force two pianists to play the same piece at the same theoretical tempo and dynamics, they will come out with different sounds anyway. It's not only a matter of placing the notes in time; it's also a matter of articulation and pedaling - thus, a matter of *sound*. So, IMO, a pianist can have *his* sound, no doubt.

 

About angels - female, they're female.

Devils too, I'm afraid. :rolleyes:

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Originally posted by meroveus:

Presumably, the sex would determine the size of the angels, no?

 

If males are bigger than females, then fewer male angels will be able to dance on the head of a pin, than if they were females.

The other factor is that males don't generally prefer to dance together unless there are females present. Females will dance even by themselves with no male present. :D

 

So... if angels are male, then only one can dance on the head of a pin. If they are female, then more than one (the exact number is up for debate) can fit. :cool:

So males are fermions and females are bosons? If I start calling my wife Boatswain Sherri she will look at me funny and say I am weird. She does anyway.
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