This is a simplified personal description of the complicated magnificent world of sound.

Panos Ioannidis


I experienced the awakening of the sense of hearing during a lifelong career on sound, tuning and building pianos. To me, if the 20th century was the century of the image, the 21st is the century of sound. We possess hi-tech instruments to accurately measure sound as electric current, to analyze its components (harmonics), to interfere in its character and yet we can hardly evaluate its beauty or its live effect on a human being.

Here we explain how a pianist can evaluate his own piano sound using the human ear and perception as the measuring instrument. Very useful as it helps the pianist on performance, the piano builder for better pianos and the listener to be granted with sheer acoustic pleasure.

Only recently we realized how complex a musical tone is and on the same time how huge capacity and ability to record minute complex sounds the human ear has. In fact we still learn more and it is exciting to realize that the more we know and understand, the more we perceive and enjoy from this “new” world of sound, like having an awakening of our hearing conscience.

When a piano hammer strikes a string, the vibration that follows gives an enormous number of partials (vibrating string segments like small strings) measuring in thousands that follow a changing pattern in time (the next few seconds). The human ear can receive all this information and in order to accurately describe 5 seconds of the middle C on graphs printed on A4 sheets, we need a belt of about 300 miles of sheets glued one next to the other.

What follows is the basics to describe a musical tone and it is surprising to see the similarities with the sense of taste when we explore a glass of fine wine: First the taste attack on the tip of the tongue which immediately swells on different groups of fruity, earthly, mineral, woody, floral tastes and so on immediately followed by an amplification and settling of acid and basic balance. All this has a duration and decay which leaves us with an aftertaste… So familiar and so useful to explore one sense with the help of another. And it is interesting to see how wine is evaluated: specialists are employed by the wine stock exchange to accurately grade companies in very serious financial decisions, instead of calling wine chemical labs claiming accurate analysis. We can do the same on piano tone evaluation. After this short description we give practical seminars that give results.

We will give 7 basic magnitudes: 1. Attack.  2. Swell.  3. Volume.  4. Timbre.  5. Sustain.   6. Decay.  7. Overtones.

This is the first millisecond of the piano tone. The hammer hits the string with a knocking noise rather than musical tone and it is the starting point of the string’s vibration. Most interesting things happen after the attack, but here we pay attention as this very short “noise” is what makes pianos so unique. This starting sound gives them character and identity and it can sound from very annoying to very beautiful and thrilling.

 A bad piano gives an aggressive powerful sharp attack that sounds like stone on metal or glass on cement, using up most of the string/soundboard energy and leaving little else to follow. This is a piano hard to listen to with very low dynamics and singing ability.

The attack on a good piano has more of a “condensed” musical tone rather than noise that immediately expands in a galaxy of sound colors, the better the piano, the less the noise. We work hard to design soundboards and matching actions in order to find the optimum line between a transparent and lively attack with all the freshness of a new note instead of a hard or lifeless bad attack.

This is by far the number one asset on a great piano. We do small compromises in a real world, but we do not compromise on swell. By definition swell proves the singing power of a piano, the ability to exploit the string 100% and to give the energy with which we can work all piano’s parameters. If there is now ample sound energy, there is no piano.

Swell describes a well-designed soundboard that does not impede the string’s minute energy after the initial hammer blow and a string/soundboard system that “breathes” and transmits all initial blow in vibration. Hence the term “swell”, as we can actually witness the sound to grow bigger after the initial attack. The longer the string, the greater the swell. Therefore bass and tenor always swell more than treble and high treble, but the swell is even there for one or two seconds.

The soundboard is not an amplifier, it is a transmitter which means that it cannot give more than the string itself. So all the game is played on the efficiency of transmission. We can compare a bad piano with an efficient piano if we compare two light bulbs: an incandescent light bulb gives 20 watts of light burning also 80 watts of heat where a LED bulb can give 90watts of pure light for every 100 watts consumption. And indeed, in physics’ terms a good piano burns less heat!

On a bad piano, the pp and ppp levels can be hardly conceived, they sound dull and nonexistent but on a good piano they sound clear with all of the piano’s character. On the other hand, f and ff levels seem to give more noise instead of sound on a bad piano but exactly the opposite on a good piano. This is why artists struggle hard increasing their mezzo line in order to have more sound on a bad piano. On the other hand when they encounter a fine piano we often watch them starting with a high mezzo and gradually lowering it as they can get more detail lower and also have more overall dynamics!

The definition of volume in pianos describes the intensity in db (how powerful the sound is). We do not agree with this and many languages use different words to describe it. To us it would be better to use the word “intensity”, not only for pianos but for all digital sound exits. Volume as we understand it describes how detailed, deep and complex the musical note is and how delicately we can interpret.

Nevertheless in order to keep it simple and universal we keep it as is. Later we will use the word timbre to describe detail and we will use the word “depth” where needed.

Volume is different than swell as it describes the power of the sound. We often find voluminous pianos that usually are just loud making noise. However it is not enough to have all good things without volume: 19th century pianos had a beautiful delicate sound, but this is not enough for us. After the magnificent mid war piano period, pianos were built faster and cheaper following “the bigger the better” rule. More tension in the strings, heavier and thicker soundboards, heavier hammers, increased key depth and acceleration, higher crowns and down bearing and so on.

The louder piano is easier to sell, it is also often preferred by recording studios and jazz pianists. So much has been invested on sound quantity instead of quality that for the last four decades it became fashionable. We can only recall the last ten years musicians to have enough of this and ask for more detail. Therefore the timing is right to bring back some of the older glory of piano sound but also claiming a bigger sound with more volume, projection and power. This is why we do not prefer to make exact copies of fine old pianos but redesign them instead, trying to fuse both worlds. And to clarify we must explain that a piano ages and has an expiry date. All these midwar period fine pianos are well beyond their expiry date, however we can precisely decode their original glory by the way they have deteriorated, the traces they left behind and their response to rebuilding.

Volume for a piano is what “body” is for a glass of wine.

Timbre for a piano is what “bouquet” for a glass of wine.

Timbre is the character of the musical note, is what identifies the instrument. It is the recipe containing thousands of minor and major harmonics. Men and women in beauty contests may have the same height, weight etc., but they have so many other details that make them distinctive and in fact some more beautiful than others. Therefore not only we deal with so many grades of beauty but also with different kinds that could be all rated equivalent. That means that sound too can have high quality standards and also be different.

It is difficult if not impossible to graphically depict the sound color. When a string vibrates, there is a multitude of vibrations in the whole length, the halves, the thirds and so on, with so many superimposed tiny vibrations that we are talking of many thousands of different sound on the same recipe, on the same string. Within limits we clearly define piano sound from other instruments but we also find great differences within different pianos. And it is very interesting to realize that this recipe is not “clean”, which means that it consists of a considerable number of inharmonic (non-matching) partials, as if some “dirt” is necessary to deliver a pleasant sound.

We deal with deep dark waters when we are called to “design” a specific piano sound. So far we had basic guide lines on string scaling but there is really a lot more to that involving most of the structure of the piano, being too much to discuss here.

A lot of headache, hard work and ability for the builder to keep under control the timber (and volume) balance and uniformity throughout the pianos’ compass.

It is about how long a pressed piano key is audible. More sustain for the bass, less for treble. Notes 80-88 sustain on high end pianos only. More and different sustain with the loud pedal pressed.

Sustain is as important as attack, volume etc. Piano builders often argue about having to compromise between sustain or volume, as they believe that one cancels the other. True to some extent but a well-designed piano needs less compromise. Once more we are faced with a multitude of factors affecting sustain. We can affect it with voicing, let alone building methods, materials and design.

Pianos with rich sustaining notes up to 88 and an expanding swelling pedal is encountered rarely on exceptional pianos only.

It is the progress of the musical note in time, most important being the first few seconds. All its magnitudes are in constant change to such an extent that we need two ways to describe a note: in time and in complexity (harmonic analysis). So much is happening after the initial attack that gives us reason to explore and work on. Normally all pianos loose energy in the first few sustaining seconds, hence the term decay. Thus when speaking about swell we really describe a minimal or zero decay for a few seconds (the plateau)  that reorganize and clarify the note’s partials.

Last but not least we need an understanding of all these peripheral sounds and noises to efficiently evaluate a fine piano. In other words part of what we accept as musical note is an assortment of other sounds and noises which usually degrade the note’s quality. This is all a bit technical, calls for practical description,  but very shortly we pinpoint the following:

  1. False beats that originate in bridge wear and string problems: differential string lengths on same partials.
  2. Buzzing wire noise from wear in capo and duplex scale. We are a bit critical on duplex scales and we usually abolish them.
  3. Harsh, muted or knocking flat sound from hammer wear or lack of voicing.
  4. Low pitched roar as the byproduct of uncontrolled soundboard vibration usually between the bass and tenor bridge.
  5. Inharmonic partials, difficult to deal with, found even in high end pianos.
  6. Sympathetic vibration on some part inside the piano.
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