Thai scales

Re Thai Scales: Graham Breed raised a question about Thai scales and
7-tone ET in TD 1104. I looked up the scale he posted in Helmholtz (p.518
of the Dover edition) and noticed that Ellis himself was somewhat dubious
about it.

Ellis (on p. 556 ) says that the King of Siam (sic) sent over his Court
Band with their instruments to the London Inventions Exhibition of 1885
and the he and Hipkins were allowed to "determine the musical scale." A
Prince Prisdang said "the intention was to divide the octave into 7 equal
intervals." However, Ellis said he found considerable deviation from the
ideal.

Ellis went on to say that the Ranat_s were tuned with lumps of wax
containing a heavy material and that all of them had been removed from
#85 (p. 518) in his tables and "hence it was entirely out of tune."

Furthermore he stated that only 21 of 52 measured intervals were between
160 and 179 cents (nominally 171).

Some "octaves" measured by Ellis:

Ranat Ek, wooden "harmonicon", 3 octaves, last incomplete
0 208 326 537 698 883 1048 1208
0 200 359 537 711 883 1057 1222
0 193 347 549 698 -- -- (two notes too high to measure)

Ranat t'hong (brass harmonicon)
0 200 340 537 699 881 1043 1207

Ranat lek (steel harmonicon) 3 octaves
0 -- 327 519 679 856 1075 1202 (2nd bar missing)
0 150 299 447 614 743 960 1179
0 90 222 430 609 (incomplete octave)

Tak'hay (crocodile, 3 string instrument with high frets)
0 198 362 528 720 890 1080 1250

Theoretical 7-tet
0 171 343 514 686 857 1029 1200

0 129 277 508 726 771 1029 1254 (#85, p. 518)

As I recall, Thai music selects out 5 tone subscales from the
7-tone gamut so the actual scales may be something quite far
from 7-tet. There seems to a tendency to stretch the octave,
sharpen the fifth and possibly the first interval as well.


--John

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