Sound help

with action script you cant know the name if you use auto.
so better use a name

playsound(rocknroll, music.mp3, false, 1);
set(sound[rocknroll].onplay, 'trace ("!");');

playsound(auto, music.mp3, false, 1);
trace('autosound=', autosound);
set(sound[get(autosound)].onplay, 'trace ("!");');

read the documentation:
https://krpano.com/plugins/soundinterface/#soundobject

well, if autosound is not a string (the name) but an object, what could it be ?
always read the docs, they are very exact !
(i didnt do that, first )

" there will be also a global variable named autosound that refers to that last created sound object. "

so...
playsound(auto，music.mp3，false，1);
trace('last name = '，autosound.name);
autosound.play(); // play later

of course autosound gets overwritten if you create another sound with auto
so it would be wise to backup the sound object for later use

playsound(auto，music.mp3，false，1);
copy(mysound, autosound);
trace('mysound name = '，mysound.name);
mysound.play(); // play later

but why not simple use your own name anyway?
playsound(mysound，music.mp3，false，1);
sound[mysound].play(); // play later