If you're looking for a bass powerful Bluetooth speaker that also happens to be waterproof, take a look at the Boombotix Boombot Bass Station. This has a 15W subwoofer in the dock which gives it even more bass. This is a pretty rugged Bluetooth speaker system, and it has two harmonized speakers that will combine and give you a portable speaker, but also the crisp sound of having a home audio system. It also has support for both Google Voice and Siri (unfortunately it doesn't have Google Assistant support), so you can control the system with your voice.
There is 2GB of local storage available, so you can store your favorite music and other audio files on-board and have even better quality audio, than if you were streaming over Bluetooth. The Boombotix Boombot Bass Station is also IPX7 water resistant, so that it can handle being dropped into up to 3-feet of water for about 30 minutes and still work fine. So unfortunately it won't be a great speaker for taking to the pool for a long period of time.
Typically this speaker would cost you around $149, but right now the Android Headlines Store is knocking 81% off of the regular price, bringing it down to just $27.95. That's a crazy good price for any speaker, never mind one with a subwoofer in the dock and being water resistant.