The following composers (and maybe more) used the term "flexaton" for the Musical saw and noted "flexaton" in the score:
- Ernst Krenek (Opera "Jonny spielt auf", 1927), who used the special sound of Harlem Jazzbands in the 1920ies, where musical saws were used as well as washboards and other domestic instruments. In this excerpt of a recording
you can listen to the musical saw from 2'30, from 2'54 and from 3'48
- Dmitri Shostakovich (opera "The nose", 1929)
- Giacinto Scelsi (Quattro pezzi per orchestra, 1959) - he noted "Sega o Flessatono", which can't be meant alternatively because of the very diverging sound character of both instruments
- Hans Werner Henze (opera "Elegy for young lovers", 1961) , to whom I spoke personally, when I played the "flexaton"-part on the Musical saw in his opera "Elegy for young lovers" in Bilbao 2009. He told me, that there were always confusion with the double meaning of "flexaton". Secondary here is a report of the premiere
(in German), where the musical saw is mentioned.
Arguments for the Musical saw and against the Flexatone in Khachaturian's Piano concerto:
The Flexatone needs to be played with tremolo (sound production with two little mellets) and normally the tremolo is specially noted as for example in the flexaton part in Schönberg's Orchestervariationen Op.31. But there is no tremolo noted in the flexaton part of this Piano concerto.
The Musical saw is a folk instrument, which is known in traditional Russian (and also Armenian) music. Khachaturian related much to Armenian traditional music, especially in this Piano concerto.
The Flexatone is no traditional instrument.
With regard to the musical context, it is probable, that Khachaturian wanted to have originally a musical saw in this concerto. In the second movement the flexaton voice goes unisono with the high violins and it's character is very lyrical. The sound of a Flexatone has always the chattering of the little mallets, which sounds like a doorbell and would disturb the lyrical character of this movement
(listen to 2).
There were recently at least three performances of this concerto with the Musical saw:
October 2013 in Berlin:
Rundfunkorchester Berlin with Nareh Arghamanyan on piano under the baton of Alain Altinoglu (CD recording a few days after the concert) > review of the CD
with reference to the original intention of Khachaturian
February 2014 in London:
London Philharmonic Orchestra with Marc-Andre Hamelin on piano under the baton of Osmo Vänskä (live broadcasting on bbc radio) > review of this concert in "The Guardian"
"the piece is memorable for including a musical saw in the slow movement"
June 2015 in Dresden:
Dresden Philharmonic Orchestra with Jean-Yves Thibaudet on piano under the baton of Bertrand de Billy < review of this concert
(in German) about the soloistic appearence of the musical saw