"I played on my setup for a minimum of 3 years without a problem. This week I received the anniversal patch for Win10 and patched D3 as well. Since then I have no sound in game. All other games work fine as ever - maybe it is related to the windows update.

Look in your D3-Folder in the D3Debug.txt
there are lines with FMOD Errors:

2016.08.07 11:11:16.157093500 Selecting driver 0 (Lautsprecher (Sound Blaster X-Fi Xtreme Audio))
2016.08.07 11:11:16.160045500 Speaker Mode: Stereo
2016.08.07 11:11:16.162816100 Initializing sound with 128 channels
2016.08.07 11:11:16.223521500 FMOD Error during 'FMOD_System_Init': Soundcard does not support the minimum features needed for this soundsystem (16bit stereo output).
2016.08.07 11:11:16.226794500 FMOD Memory - total: 178257920
2016.08.07 11:11:16.229558100 FMOD Memory - allocated: 26272, - max allocated: 69416
2016.08.07 11:11:16.232502100 Sound subsystem failed to initialize!
2016.08.07 11:11:16.236008800 GameDisposeGames()

I switched to onboard sound (Realtek HD Audio) this is working so far."