i have a customer who just had a bathroom installed. i had nothing to do with the rough in of this--only the trim.
he is unhappy with his shower, in that the drain makes a lot of noise while draining.
he asked me if i knew of a way to suppress the noise.
i told him no, but i know who might, which brings me to you all today.
this is an upstairs bathroom with no access to the trap without tearing open a ceiling.