Vibrations and Partial Tones
The distinctive and dynamic characteristics of the Stuart piano sound are identified in the following chapters by visualising and listening to the harmonic makeup its soundscape. The musical shapes and colours of piano sound are explored by examining the wave forms and vibrations that combine to create the sound. The elements of piano tone description, amplitude, attack, sustain and decay are described in terms of their transient levels over time, as piano sound is in a constant state of transition. The hammer strike excites the string into its full spectra of sound after which the string’s oscillation and sound spectra gradually diminishes.
No stationary state is created for the piano sound, since there is no uniform continuous excitation. Nevertheless, quasi-stationary conditions can be assumed as an approximation at least for short durations. As a result, spectra of partials can certainly be used for the tonal description of the sound during its initial phases, however the time structure, and above all the decay behavior play a much more important role than in string and wind instruments.167
In this chapter I explore definitions of tone quality and explain how I have identified tonal characteristics of the Stuart sound.
Throughout this research I compare the sounds of the Stuart concert piano (M19,STU) to the sounds of the Steinway concert D (STE)168 as a method for identifying the new and distinctive sounds of the Stuart soundscape. The Steinway D provides a ‘control’ of the tonal qualities produced by the modern piano.169 When the sounds of both pianos are heard in the same room, it is audibly clear that fundamental attributes of the Stuart soundscape are different to those produced by the Steinway. The audio samples below demonstrate the sounds of both pianos, of the note C5 523.23Hz.
| Stuart 2.9m 2002 No 19 | Steinway D 2005 No 574500 |
| C5 v54 STU MW mxd array.wav | C5 v54 STE MW mxd array.wav |
| C5v54 MW mixed array. Soundtable 3.1 | |
The sounds of the Stuart and Steinway pianos were obtained for evaluation by recording the pianos in a controlled acoustic sound field. From a thorough examination of approximately 96 recorded tones, I identified four distinctive characteristics in the sound of the Stuart piano that differ to the sound of the modern piano:
- A slower rate of decay in the fundamental partial frequency
- An earlier transition into the after-sound states of string oscillation.
167JürgenMeyer, Acoustics and the Performance of Music. Frankfurt: Springer 2009) ,116.
168 The Pianos in Comparison – see chapter 1.
169 see“Modern Piano,’ p.17.
