New 30’ diameter swimming pool needs weatherproof out door audio system, powered speakers

This may not be the forum for this question, but perhaps someone can point me to a speaker system, or online dealer.  A friend has put in a 30’ diameter outdoor salt pool that needs some powered wireless speakers to listen to, mostly rock music.  I assume he’ll control music from iPhone, not sure what service.

Can anyone recommend a mfg of good to excellent equipment?  He is an engineer, so quality and reliability are important.  He built the pool himself, but is no audiophile.  I understand this is an unusual question for you all.

My other thought is to call Crutchfield online.

any input appreciated

thanks