Up to what degree does a pianist control sound in his instrument?

[Enrique]

In an excursion I made into another music forum, I read this:

As you have no doubt noticed, harpsichord sound varies much more widely than piano sound.

I know nearly nothing about the mechanism of sound production in a piano, except that some thirty parts are involved for each key (the action), let alone the harpsichord. But application of logic along with some rudiments of acoustics allows me to draw some conclusions. So I wrote:

How is that, Noseeum? Would you care to expand the concept? If we agree that sound can be characterized by three elements and only three elements, namely, pitch, intensity and timbre, then we have: pressing a key in either instrument determines the pitch, and it also determines the timbre, because in such complex devices as keyboard instruments are, the sound comes "prefabricated". I mean, pressing a button (key) just triggers a complex mechanism whose output is the sound you hear. The clavecinist or pianist does not intervene in the production of sound, as is the case in a violin, for instance, which being a much more primitive instrument, lets the player to actively control the quality of the sound. In this way, each key in either instrument, harpsichord or piano, has an associated predetermined timbre, which no player can alter (the use of the pedal introduces a slight complication here which for the moment I'll shall not consider). There is only one variable left: intensity. And here you have that the piano has a huge dynamic range, which makes it possible to play from a pppp to a ffff and, in fact, an infinite number of dynamic levels.

I'm sure most of pianists would disagree with this explanation, but I would only be willing to hear speak a pianist who has grasped the elements of acoustics (these principles are indeed taught at conservatories but the professional pianist will nonetheless insist in that he controls the timbre in his instrument).

My whole refutation would lack meaning or the greater part of its force if the poster would consider that a pianist has any kind of control over timbre. What do you, fellow BRSers, think about this matter?

[Peter]

No I don't agree - the quality of tone is very much controlled by a pianist's touch and this goes beyond mere dynamics.

[Enrique]

But tell me, Peter. What happens when you press a key is that the hammer will strike the string (one, two or three strings depending on the key). And in how many ways can the hammer strike its string? In only one way, namely, with a certain momentum which, given that the hammer has a fixed mass, translates into "with a certain velocity". That is, the only thing you can control is the hammer speed the instant it strikes the string. There is absolutely no other variable you can control. Or is there any? Please do not trust your ear in this. Your ear can deceive you in a thousand imaginable ways. Trust only logic.

Different speeds can produce different timbres? I concede it. There will be a very slight variation in timbre, which is what I think you refer to with the expression "quality of tone". But every time the hammer travels with a speed of 10 inches per second the timbre will be exactly the same.

There is still another consideration, another variable. How long does the hammer remain in contact with the string? Well, this time will only depend on the particular action mechanism the piano has. Never on the pianist. But you trust your ear better than logic or physical theory. OK. Then let instruments be the ultimate judge in this matter. An ultra high quality microphone, amplifier and oscilloscope will let you see a faithful graphical representation of the sound when the hammer strikes with, say, a speed of 8 inches per second. And you will see that, each time the hammer strikes at 8 in/sec, the waveform will always be the same (and the associated frequency spectrum too, of course). Of course, the sound will continue until the moment the damper falls and the waveform will be subjected to a continuous variation during all that time. But it will always vary in exactly the same way.

I think these arguments are conclusive. You, at the other end of the action mechanism, can control only one thing: the speed with which the hammer strikes the string.

[Peter]

Through the use of arm weight - a common misconception is that if a passage is soft you strike the key with less weight than in a loud passage, not so. What affects the dynamics is the speed of the key descent - the weight affects the quality of tone.

[Peter]

I should also add that not just the arm weight but the approach to the key will effect the tone - for example a stiff wrist will produce a harsh tone.

[Enrique]

I will not try to change the mind of someone who has been teaching piano for a good span of his life with a couple of posts. In order to change your ideas and those of so many people that share yours I would have at least to write a book. I recognize that. However, if you were willing to reflect a bit in my words, you would understand my argument. It is so simple!

You may strike the key in as many ways as you like. With the full weigh of your body or by just articulating one of the phalanxes of a finger. All of these actions will translate into one and only one thing: hammer velocity. This is my whole argument! Just think a bit of it.

[Peter]

I will not try to change the mind of someone who has been teaching piano for a good span of his life with a couple of posts. In order to change your ideas and those of so many people that share yours I would have at least to write a book. I recognize that. However, if you were willing to reflect a bit in my words, you would understand my argument. It is so simple!

You may strike the key in as many ways as you like. With the full weigh of your body or by just articulating one of the phalanxes of a finger. All of these actions will translate into one and only one thing: hammer velocity. This is my whole argument! Just think a bit of it.

You're trying to argue with your mind instead of your ears! Go to a piano and just play a chord and you will find there are many different sounds possible. If you want a book, you needn't write one, there already are plenty on the subject and you could begin with Matthay's 'The Art of Touch', but be warned it is heavy going!

[Enrique]

I think that if these post are to have any meaning at all, we should first agree on what we are speaking about. Firstly, we should agree we are speaking about timbre, which is a well defined property of musical sounds. So, I think we should try to agree on the truth of falsity of the following statement or proposition: "Musical sounds can be characterized by three and only three properties: pitch, timbre and intensity (loudness level)". My thesis is this: when playing a single note, the pianist cannot control timbre. All he has control over is intensity. As you can see, Peter, this is a very modest statement. That's all I am saying.

[Peter]

I think that if these post are to have any meaning at all, we should first agree on what we are speaking about. Firstly, we should agree we are speaking about timbre, which is a well defined property of musical sounds. So, I think we should try to agree on the truth of falsity of the following statement or proposition: "Musical sounds can be characterized by three and only three properties: pitch, timbre and intensity (loudness level)". My thesis is this: when playing a single note, the pianist cannot control timbre. All he has control over is intensity. As you can see, Peter, this is a very modest statement. That's all I am saying.

I know and I still don't agree I'm afraid - I can play a note softly and produce different tone quality, it isn't just about dynamics. A note with little weight used played piano will have a thin sound, whilst one played piano with the arm weight sinking to the key bed will have a richer fuller sound, but not louder! Equally if I strike a key forte without relaxing through the note the sound will be harsh or 'stabby' as we say, but played with a relaxed wrist equally loud it will not.

[Junggai]

This has to be one of the most frequent debates heard in pubs around conservatories around the world. As I understand it, the difference that pianists feel and hear in the sound when altering the touch has not been adequately studied by experts in musical acoustics, but the first results are promising.

Here's what we know:

It's not true that the only component affecting the vibration of the string is the velocity of the hammer as it hits. The shank of the hammer (in other words the stick that holds it) is made of very flexible wood, and depending on the way the key is struck, its flex can vary greatly by the time the hammer hits the string. This means that the hammer hits at a slightly different angle depending on the acceleration. Just how much this affects the sound still has yet to be studied in detail, but the differences in hammer motion have been observed. (See a scientific discussion here and here.)

There's also a lengthy and interesting discussion of this issue on p. 66-69 of this book by Chuan Chang, a scientist who dabbles in piano--full disclosure: he's a friend of mine. Chang is more convinced that the acceleration of the hammer affects the overtone distribution, which is something that I as a pianist can agree with. Experientially, there's no way that a pianist's touch has zero effect on the timbre independent of dynamics. Scientists just need to find the right set of questions.

[Enrique]

It should be clear that this matter belongs to the field of acoustics and, hence, it is the physicist who we should hear. And what do physicists say?

Physicists usually claim that as the mechanical contact between the key and the hammer is broken before the hammer strikes the string, the pianist can only influence the final velocity of the hammer and thereby the loudness, and nothing more. Many pianists on the other hand, claim that important shadings in the character of the notes can be achieved by applying different types of touch, and that such a skill is an important component of the art of piano playing.

--From Junggai's link.

Personally, I think there is here the same kind of mythology we find around the famous curve ball of baseball. Timbre can be accurately described in scientific terms. It's all about the frequency spectrum of a given sound. And frequency spectra can be very accurately measured. All we need is a scientist that gets interested in these things.

[Chris]

Fortunately I don't have to worry about this because my piano technique has been completely ruined by years of playing on a digital one.

[Junggai]

It should be clear that this matter belongs to the field of acoustics and, hence, it is the physicist who we should hear. And what do physicists say?

Personally, I think there is here the same kind of mythology we find around the famous curve ball of baseball. Timbre can be accurately described in scientific terms. It's all about the frequency spectrum of a given sound. And frequency spectra can be very accurately measured. All we need is a scientist that gets interested in these things.

Enrique, later on in the same lecture you quote from , these acoustic scientists demonstrate that touch does indeed affect the hammer motion independently from velocity, but they admit that further research is needed on how it affects the sound. The other link has an extended discussion of the issue with reference to physics.

So with all due respect, this is not just "mythology," it's science catching up with what pianists have long known instinctively.

[Junggai]

From this page of the Askenfelt/Jansson study I linked to earlier:

"Depending on the touch, the motion of the hammer can be quite different, even when the dynamic level is kept constant. The examples in Fig. 11 show the hammer velocity and acceleration for three different types of touch as measured at the hammer head. Indeed, the motion of the hammer before string contact is different in the three examples, despite the fact that the final velocities were approximately the same. At the moment it may suffice to note that the hammer motion seems to involve two components of oscillation, which are excited differently depending on the touch. One is a slow "backwash" motion at about 50 Hz and the other is a "ripple" type motion at about 400 Hz. While the slow motion is more prominent in the gentle types of touch, the "ripple" motion seems to be a characteristic of the vigorous, impulse-like types of touch."

[Enrique]

Well alright, there is a tiny difference in the hammer motion at the time of contact with the string: now the question is how it affects the resulting sound. This should be measured with instruments. Is the differerence so big that the human ear can detect it? From the same page:

The perceptual differences between these notes were only rated informally. The pianist described the differences in tone character as large, but the experimenters on the other hand, had the impression that the differences were rather subtle. A formal evaluation would need a reliable listening test according to one of the recognized (and elaborate) methods prescribed by music psychologists, including a close control of the dynamic level.

Be it as it may be, you would agree that in wind and bowed string instruments there is much greater control over timbre than in the piano. Maybe there will come somebody saying that in the pipe organ the player can control timbre by means of the touch!