सङ्गीतरत्नाकर: प्रथम भाग (शार्ङ्गदेव - स्वरगताध्याय सविस्तार व्याख्या व अनुवाद सहित)

150 Treatment of Svara
It is important to note that Mataṅga lays down the condition of
the notes being of identical śruti-measure, in addition to the required
note-interval of nine or thirteen śruti-s. Following Mataṅga, Abhinav-
gupta elaborates the concept of samaśrutikatā (identity of śruti-measure)
of a tone with reference to the last śruti of the preceding tone. Thus
Bharata has enumerated the following pairs of consonant notes in the
ṣaḍja-grāma : sa-ma, sa-pa, ri-dha and ga-ni based on 9 and 13 śruti-
intervals. What is notable is that he has not included the pair of ma-ni
which implies a 9 śruti-interval. This is so because ma and ni being at a
distance of 4 and 2 śrutis from the last śruti-s of their respective preceding
notes are not identical in their śruti-measure. Thus the phenomenon of
svara-saṁvāda which is inaccurately identified as the consonance of notes,
is not only an acoustical but also a melodic phenomenon. In the former
case it signifies the relation of svara-s in terms of the śruti-interval obtain-
ing in-between them and in the latter case it refers to the identity of śruti-
measure constituting them. The melodic effect of this aspect of svara-
saṁvāda is amply demonstrated by reciprocal triads formed by the con-
sonance of notes as defined above. For example, Brihaspati points out that
in case of ma-ni, which has been excluded by Bharata from the consonant
pairs, 'ma-ga-ri' cannot be reciprocated by ni as 'ni-dha-pa', the reciprocal
triad would be 'sa-ni-dha' and not 'ni-dha-pa'. Hence ma-ni have not been
spoken of as having saṁvāda" (cf. I.M.J. No. 7, p. 60 and P.L.S.: I.M.J.
Nos. 11-12, p. 57).
Incidentally the minute difference between the concept of conso-
nance in western music and saṁvāda of Indian music is also made clear
through the concept of samaśrutikatā.
Furthermore, as 'S' explains, Mataṅga includes the note-śruti of
the note with which consonance is established in the number of śruti-s
forming the interval, whereas Śārṅgadeva excludes it; that is why
Śārṅgadeva speaks of eight and twelve śruti-interval and (Bharata),
Mataṅga and Dattila add one more to state as nine and thirteen-śruti-
interval. For example, take the consonance of sa-pa. The note-śruti
of sa is 4th and that of pa is 17th; and if, while measuring this interval,
one counts from 4th (including it) to 16th it would make for a thirteen-
śruti interval but if the 4th is excluded, then it would make for a
twelve-śruti interval. The consonance of notes is reflected in the
following chart :
Section 3 : Nāda, Śruti and Svara 151
Sonants and consonants

Sonants	consonants	note-interval of Śārṅgadeva	note-interval of Mataṅga	Relation
Sa	(i) ma	8	9	ṣaḍja-madhyama
Sa	(ii) pa	12	13	ṣaḍja-pañcama
Ri	dha	12	13	"
Ga	ni	12	13	"
Ma	sa	12	13	"
Pa	sa	8	9	ṣaḍja-madhyama
Dha	ri	8	9	"
Ni	ga	8	9	"
(Chart 10)
It will be clear from the above chart that even though all the notes
have their own consonants in turn, yet only two relations of consonance,
viz., the 8-śruti and the 12-śruti intervals are recognised; and these are
respectively known as the ṣaḍja-madhyama relation and the ṣaḍja-pañcama-
relation.
But what is the function of the consonance of notes in perfor-
mance ? 'S' explains on the authority of Mataṅga (obviously) that,
the underlying principle is that a consonant note can replace a funda-
mental note (i. e. tonic) without damaging the spirit of the mode and
the rāga (the melodic pattern). For example, in case of sa-pa consonance,
if in a given composition sa is the fundamental note and it is substituted
by pa, it would not adversely affect the value of the aesthetic potential
of the melody.
It may also be noted that even though Mataṅga concedes the
relationship of consonants only between the notes of identical or equal
śruti-measures, Śārṅgadeva in agreement with Dattila does not mention
this condition. Thus he would admit consonance between whatever
notes that are placed at the distance of 8 or 12 śruti-s.
Now with regard to the dissonant notes the author presents two
or three views altogether :
(i) that ga and ni are dissonant to all other notes
(ii) that ga and ni are dissonant to ri and dha
(iii) or/and ri and dha too are dissonant to ga and ni.
The underlying principle, however, seems to be that the notes
having two śruti-s are dissonant. This is enunciated by Mataṅga when