I need to build some speakers into a stone wall like the photo shown below.  This will be a 70v system and I'd really like to have the tap available from the front so it can be adjusted once the speakers are installed.

I'd normally use JBL Pro for this, but the taps are on the back.  Anyone know of a suitable speaker with tap behind the front grill?  I've never taken a JBL Control 25 apart, so I  might also be able to just modify a pair?

The application is one pair of speakers placed in the stone wall.  Stone wall is above the end of a pool and will have a waterfall cascading over it into the pool.  There will be a bench seat built into the pool allowing you to swim up and sit behind the waterfall.  Client wants music while sitting behind the waterfall.