In the discussion of section 1 of the Gershwin video extract above, the attribute ‘bright’ was used to describe the sounds of the treble register of the Stuart sound and the bass register of the Steinway sound. It is well known that the register or frequency of pitch is a factor in influencing the character of timbre, ³⁵⁷ and in this example we hear the effects of each piano makers’ manipulations of the tonal characteristics of each register as well as their individual design implementations of the string- bridge coupling, string length, string width, string material, sound board mass and thickness.

The audio extracts revealed also that the volume, or weight applied by each pianist in the playing of a phrase, was indicative of the type of tonal colour each instrument projected to the audience. The pianistic interpretations of the music, and their relative pianistic styles therefore influenced the tonal quality of each instrument.

Earlier in this chapter we saw how the varied pianistic styles of both pianists playing in concerts No 1, 3,& 6, has influenced the perceptions of the audience regarding the associations of piano sound with genres of music and pianistic style. The Stuart piano sound was perceived by a majority of participants to suit the playing of Kevin Hunt and to suit Jazz music more than the Steinway. And the Steinway was perceived to suit both Classical music and Simon Tedeschi’s pianism, more so than Stuart. The difference in the qualities of timbre of each piano sound played by pianists of contrasting stylistic backgrounds and techniques illustrated in the audio-visual Gershwin excerpts, warrants the question, does the pianist or the piano have a greater influence on the tonal colour of the instrument?
The evaluations made of the sounds of the Stuart and Steinway at performances, at the hands of the pianists, brings into question how much the pianist is affecting the tone colour. So the audience perception is not only about the instrumental sounds, but how the pianists play the instruments.

The extent to which the pianist is able to influence the tonal colour of piano sound by particular touch has long been a point of conjecture between pianists and physicists. The argument is based on whether it is types of touch, or only the speed of key contact, velocity, which influences piano tone quality.³⁵⁸ Pianists naturally believe that the timbre of piano sound is affected by many types of contact the fingers have with the keys, and the physicists say because there is no connection with the pianist’s key-touch whilst the hammer is in flight, the only measure of influence of the pianist is velocity, or the speed of the hammer flight. We know that as the velocity of the hammer contact with the string is increased, not only the loudness increases, but the ‘brightness’ of tone increases, because the contact time of the hammer on the string is reduced by a compression of the hammer felt density on contact, which in turn excites more high partials in the string to oscillate, a process Roederer describes as loudness-timbre coupling.³⁵⁹ Roederer lists other ways the pianist can affect tone psycho acoustically:

^{357     11}Meyer,30.
^{358     3} Askenfelt,A. Jansson,E. “From Touch To String Vibration,”Five Lectures on the Acoustics of the Piano, Royal Swedish Academy of Music
^{359     18} Roederer,124.