Hey everyone, I haven't seen this posted yet and a bunch of people have asked me about this so here is a quick guide on how to remove annoying sounds (like the weather machine and mechano hog) from your client.
Open the MPQ editor, browse to your wow folder and go to the DATA subfolder. Open common.mpq with the editor.
You can now find any sound file you want to get rid of. Delete the sound file in the mpq editor. Done!
NB: Weather machine sounds are in sounds>spells and called Goblin_weather_machine_lightning.wav etc. Mechano hog sounds are in sounds>vehicles>motorcyclevehicle
Edited: January 19, 2022
Reason: no need to replace the wav file with an empty one, it actually works better just deleting the wav alltogether.