Cool --

I've never been to that particular place (in Ayutthaya Thailand), but I've seen elephants actually playing an oversized xylophone-type instrument at the elephant training center / hospital in Lampang Thailand, a couple hours from my home.

Those elephants could play a simple melody, given a mallet held in the trunk and an instrument large enough to accommodate their trunk dexterity. I didn't see the mahouts / handlers exerting any sort of direct control over them while they were playing, so I think that they remember the songs, timing, etc. all internally. This elephant bobbing along with the music suggests that they have rhythm and an innate enjoyment of the music, also.

Amazing animals, and cool to watch!