I've seen a few threads on this subject, and there seems to more people saying they have issues with the Nokia 3650 and sound than not.
Currently, we have a game that we are porting to the Nokia phones. For the Series 40, we have both an OTT and MIDI implementation that works.
When we go Series 60, using the same code, the OTT "plays" but does not have any audible tones. This is true for the emulator and the real phone. For MIDI, on the emulator, the game crashes (even though we are catching exceptions) on a prefetch. If I look at the state, it is 200 (REALIZED). But I cannot play the MIDI. We are about to do testing on the real phone.
We are using the 2.1 version of the SDK (Series_60_MIDP_SDK_2_1).
Our code is relatively simple, and we have actually taken test code from this forum as well, seeing similar results (no audio).