I know setCustomSoundController exists and you could use that to do something like this but that means you would have to have access to modify all possible vehicle configs for all mod/cdlc vehicles that might use customized soundshaders for vehicles, so:
<vehicle> getSoundShaderParams <soundshader>
Would return the current values of all the given sound shader values for the given vehicle.
_tank getSoundShaderParams "MBT_01_Drive_Water_INT_SoundShader";// Would return an array like [["volume", 0.786], ["frequency", 1]]
[<vehicle>, <soundshader>] setSoundShaderParams [["volume", <value>], ["frequency", <value>], ...];
Would allow setting the soundshader values.
[_tank, "MBT_01_Rain_INT_SoundShader"] setSoundShaderParams [["volume", 0]]; //no raindrop sounds inside given tank