Comm. NT: 22.
See also §134 and notes 60, 61. The amplification in this paragraph is from Vism- mhṭ, which continues:
Rūpakkhandhakathāvaṇṇanā
“There is another method: the eye and the ear have non-contiguous objective fields because arising of consciousness is caused while their objective fields are separated by an interval and apart (adhika).
Some say that the ear has a contiguous objective field.
If it did, then sound born of consciousness would not be the object of ear-consciousness,
for there is no arising externally of what is consciousness-originated.
And in the texts sound as object is spoken of as being the object of ear-consciousness without making any distinction.
Besides, there would be no defining the direction and position of the sound because it would then have to be apprehended in the place occupied by the possessor of the objective field, as happens in the case of an odour.
Consequently it remains in the same place where it arose, if it comes into focus in the ear avenue (so the Burmese ed.).
Are not the sounds of washermen [beating their washing on stones] heard later by those who stand at a distance?
No; because there is a difference in the way of apprehending a sound according to the ways in which it becomes evident to one nearby and to one at a distance.
For just as, because of difference in the way of apprehending the sound of words according to the ways in which it becomes evident to one at a distance and to one nearby, there comes to be [respectively] not apprehending, and apprehending of the differences in the syllables, so also, when the sound of washermen (a) becomes [an occurrence] that is evident throughout from beginning to end to one who is nearby, and (b) becomes an occurrence that is evident in compressed form in the end or in the middle to one who is at a distance, it is because there is a difference in the apprehending and definition, which occur later in the cognitive series of ear- consciousness, that there comes to be the assumption (abhimāna) ‘Heard faintly is heard later.’
But that sound comes into the ear’s focus at the moment of its own existence and in dependence on the place where it arises (see XIII. 112; Dhs-a 313).
If there is absolutely no successive becoming of sound, how does an echo arise?
The sound, though it remains at a distance, is a condition for the arising of an echo and for the vibration of vessels, etc., elsewhere as a magnet (ayo-kanta) is for the movement of iron” (Vism-mhṭ 446–47).