Sound Research WIKINDX

The definition has the following footnote: "Not all sounds evoke an auditory sensation, e.g., ultrasound or infrasound. Not all auditory sensations are evoked by sound, e.g., tinnitus."

In rejecting the idea that sounds are proximal stimuli (cf. (O'Shaughnessy 2009)), a number of arguments are used including:

• if sound is at the hearer's position then the number of sounds = the number of listeners
• Failing this, then a single sound can exist in multiple locations

Also rejected is that, while the fact that the sound of something distant sounds different if one were close up (an argument for sound as proximal stimuli), that we have no notion of distal volume or loudness of a sound—we do. A motorcycle at a distance can still be judged to be loud.

The fault, apparently, is that the proximal stimulus theory does not "distinguish between source and informational channel." Thus, the information derived from a sound wave includes not only information about the original sound wave but also filtering in the medium, reflections, absorption, echoes and so on.

Another fault is that our everyday experience locates sound where the sound wave source is.

O'Shaughnessy, B. (2009). The location of a perceived sound. In M. Nudds & C. O'Callaghan (Eds.), Sounds & Perception. (pp. 111–125). Oxford: Oxford University Press.

Arguments against the medial/wave view include:

• the existence of infrasound and ultrasound (the same physical nature as other sound waves but not sensed)
• a sound wave does not necessarily depend on the physical property of the sounding object (cf loudspeakers)
• as with proximal theories, medial theories do not locate sounds where our everyday experience would locate them (at the source and so at a distance and unmoving)
• if sounds were sound waves where then is the information contained in them that informs about the sound source, its distance, the sound's loudness, and so on—everything that we experience in everyday perception of sound?

• Sound is a property. Like colours, smells, and shapes, sounds are secondary qualities being sensory qualities. One might object that an object does not have a sound—unlike the object that has a smell, colour, or shape—rather the object produces a sound. Another objection is that sounds are dynamic and "intrinsically temporal entities" and, unlike colours and shapes, are individuals.
• Sound is a located event. Sounds are events that happen to material objects. They are located at the material source and can be identified with, or at least supervene on, the vibrations of that object. A medium is required to transmit the sound to a listener but is not required for the sound' existence—a tuning fork in a vacuum still produces a sound; it simply cannot be transmitted to us. In this theory, sound is also an "intrinsically temporal entity." Nevertheless, sounds can also be mislocated, as with echoes, and the Doppler effect might suggest that sound is in fact medial. However, a proponent of this distal theory would simply argue that it is the medium that affects our perception of pitch change—to anyone remaining with the sound source, the sound does not change. Other objections are typically countered by the charge that the objector confuses sound with a sound wave.
• Sound is a relational event. Sounds are events involving both source and medium. Developed from Aristotle's statement "everything that makes a sound does so by the impact of something against something else, across a space filled with air" (De Anima II.8 420b15). This is usually taken as an argument for the medial view of sound as a sound wave but has been interpreted by O'Callaghan to mean that sound waves are not the sounds themselves but the effects of the sounds. Thus, the medium is required for sound and so sound does not exist in a vacuum.
• Sound is the disposition of an object to vibrate upon being stimulated. In this way it is like colour which might be explained as the disposition of an object to reflect white light in a particular way. Without vibration, objects may well have sounds but they cannot be heard. Hitting, or 'thwacking,' an object is aking to shining white light upon an object—it reveals the sound as the light reveals the colour. An objection might be that, in fact, there are many dispositions to vibrating/sounding when thwacked as illustrated byt the different vibratory characteristics of an amplitude envelope. Equally, there are many types of thwackers that can be used, each eliciting a different vibration and sound. What also of the sound that lasts once the vibrational disposition has ceased? We also hear sounds as unfolding over time which is more process and event than disposition.

It seems that there is always some echo, but not always a clear one. For the same occurs with sound as with light; which also is always reflected

Aquinas claims that there is air on both sides of the eardrum, and that when we hear the inner air echoes the outer sound. Echoes, Aquinas may have thought, are like reflections in that (a) when you hear a whistle echo off a canyon wall the rock is not sounding (as the mirror does not become red)-it is the whistle that is making the noise; (b) the whistle causes the echo; and (c) when you hear the echo you are hearing the whistle."

Riddoch proposes three types of non-cochlear sound:

• Synaesthetic -- the perception of sound via stimulation of another sense.
• Infrasonic sound -- sound waves below 20Hz can be detected by the skin and the chest cavity resonates at 80Hz and below. Riddoch also points to the example of profoundly deaf (from birth) percussionist Evelyn Glennie who maintains that hearing is a specialized form of touch (Glennie 1993).
• Auditory imagination -- including memory, imagination, hallucination, dreaming which all excite the auditory cortex.

Glennie, E. (1993). Hearing essay. Retrieved April 28, 2014, from https://www.evelyn.co.uk/hearing-essay/