"Modern Indian Gamut" (JI)

In message:

/tuning/topicId_29371.html#29376

and in an earlier ATL post,
Paul Erlich relates a 13-tone (including 1/1 and 2/1) set
as being a (JI) "Modern Indian Gamut":

<< The "Modern Indian Gamut" is
S 1/1
r 16/15
R 9/8
g 6/5
G 5/4
m 4/3
M 45/32
P 3/2
d 8/5
D 27/16
n 9/5
N 15/8
S 2/1

and the 22-tone sruti system is usually given today as
S 1/1
R1 256/243
R2 16/15
R3 10/9
R4 9/8
G1 32/27
G2 6/5
G3 5/4
G4 81/64
M1 4/3
M2 27/20
M3 45/32
M4 729/512 (occasionally given as 64/45 instead)
P 3/2
D1 128/81
D2 8/5
D3 5/3
D4 27/16
N1 16/9
N2 9/5
N3 15/8
N4 243/128
S 1/1 >>

Anyone have any thoughts as to why the 27/16 pitch ratio
is chosen? Does it work well with particular other notes
and/or structures of notes?

Does anyone know of the use of 5/3 as an alternate?

Curiously, J Gill

--- In tuning@y..., J Gill <JGill99@i...> wrote:
>
> Anyone have any thoughts as to why the 27/16 pitch ratio
> is chosen? Does it work well with particular other notes
> and/or structures of notes?

Typically, there is a drone with pitches 1/1 and 3/2. But I think the
reason 27/16 is chosen is to make two melodically equal tetrachords:

1/1-9/8-5/4-4/3 = 3/2-27/16-15/8-2/1

> Does anyone know of the use of 5/3 as an alternate?

5/3 is supposedly used in many ragas. There are hundreds of
selections of roughly 5 to 9 tones out of the 22 that are supposedly
used in the various ragas.