A strange thing happened ...
The third option in SoundNote
specifies the instrument to use. If I evaluate:
EmitSound[Sound[{SoundNote[0, 0.1, 1], SoundNote[0, 0.1, 2]}]]
... it works fine (under 10.3 and 10.4). But when I added a third instrument today:
EmitSound[ Sound[{SoundNote[0, 0.1, 1], SoundNote[0, 0.1, 2], SoundNote[0, 0.1, 3]}]]
... then a message appeared: Downloading from Wolfram Server
... and if there were several such sounds, it could take minutes to download ... and eventually it would play. This is under Mac OS X 10.9.5. In the past, it just worked automatically without needing to download any sound files from the Wolfram server.
I have now tried the same thing again ... and it is working fine, without downloading anything from the Wolfram server. So, I am a bit confused.
In an earlier stackexchange question:
... an answer suggested playing this combination from the Help Documentation:
EmitSound[Sound[{SoundNote["C", {0, 4}, "Oboe"], SoundNote["G", {1, 4}, "SynthVoice"], SoundNote["C5", {2, 4}, "Organ"], SoundNote["E3", {3, 4}, "VoiceAahs"]}]]
When I tried that this afternoon, instead of playing instantly (as must have been the case when the question was originally posed), it took about 30 minutes to download the voices ... now it is working automatically.
If the files have now been downloaded ... have I downloaded all the voices? Or only some of them? Is there a way to download all the extras, so that one has the full package?