Mario Kart 8: Some sounds underwater are really quiet
Whenever the kart is underwater in Mario Kart 8 some sounds are really quiet, while others maintain their volume (like the music and drift sounds). You can hear the sound effects, but the volume is lower compared to the game on the real console (I believe the volume of those SFX also is lowered on the Wii U but not as much as on CEMU).
Game on Wii U: https://www.youtube.com/watch?v=dPm2N8Q1rhw (0:27 - 0:38)
Game on CEMU 1.17.0: https://www.youtube.com/watch?v=qv30qHp-3EQ&feature=youtu.be (0:30 - 0:43)
If you compare both videos starting from 0:27sec on the first and 00:30sec on the second it's easy to tell sounds like the coins and the character sounds are quieter on CEMU.
PS: I also checked and my setup is configured to stereo. All sound drivers are installed too without any effects activated, also tested with HDMI audio, with and without earbuds. Same result.