Throughout chapter four the illustrated piano sounds are accompanied with audio .wav files, listed in the audio tables. The audio of these sounds is accessed from the accompanying USB drive.The sound table below presents the specific sounds of C2v81 mic2, of the Stuart piano (STU) and the Steinway piano (STE) showing the sounds are found in the USB Audio folder : 4.1, tracks No 15 &16.

Attack, Sustain and Decay – transient attributes of Piano Sound.

The attack, sustain and decay transients are transitional measures of the attributes of sound.These attributes combine to form particular envelopes of sound which are described in terms of their transient level at particular time plots of the sound’s duration. The transient value, as opposed to the steady state of a sound, simply indicates that the value is not a fixed value, due to the continuing decay of the piano sound.

The typical order of events in the sound envelope sequence attack- sustain-decay is appropriated to piano sound description, though the plotted transient value of sustain is not explored in detail in this study. A sound that is described as having ‘more sustain’, in this study is a description of a sound with a slower rate of decay.

Attack

The hammer strike excitation makes the string vibrate in a vertical plane, creating a vertical vibrational force that is transmitted at its maximum amplitude through the bridge of the soundboard.

As the string is stuck, or excited by the hammer, the string vibration does not immediately oscillate at its maximum amplitude. The time it takes to reach the full oscillation, or the build-up is known as the onset transient or the attack transient, measured in milliseconds(ms). In most of the sounds examined in this study, the attack transient is audibly faster than in the Steinway sound.

The full spectrum of the piano sound is heard before any partial tones begin to decay.¹⁹⁴ In many of the piano sounds examined, the full spectrum of the Stuart sound consistently arrived earlier than the full spectrum of the Steinway sound. This often seemed to produce a more percussive and bright sounding onset.

The onset of a tone is a most important attribute for timbre and tone identification.During this transient period, the processing mechanism in our brains seems able to lock in on certain characteristic feature’s of each instrument’s vibration pattern and to keep track of these features even if they are garbled and blurred by the signal from the other instrument. ¹⁹⁵

^{194     3} Campbell& Greated ,14 .
^{195     6}Roederer,168-169.