Installing in-wall speakers in an exterior basement wall
Never mess with basement walls. This is not toung in cheek. If you want to add wiring go surface mount! I say this from working with several homes below grade from the west coast to the great Lakes area.  Changing vapor berriors or drilling walls cutting channels are all opportunitys to create leaks in a dry basement. I am not a high tech audiophile but have made mistakes 2x in below grade wiring that caused me to have to do a bunch of work from the outside to eliminate the new leaks I created and these were on my homes, lessons learned for me I hope you don't repeat.