Well basically there are two types of mics..dynamic and condenser (there are also ribbon mics and piezo mics but lets not talk about that) obviously those two types of microphones sound totally different but no one can say that condenser mics are better that dynamic, although dynamic microphones tend to compress the sound more.
If you want to record a choir (or something similar) you will need three microphones (condenser ones for sure) and you must apply a certain stereo technique which i can mail you in more detail if you are interested. Also you can find one figure of 8 microphone and place 2 people on one side of the mic and the other 3 on the other side, like they used to record musicians in the 60's. But with this technique you have to route the signal in a second channel and reverse the phase.
Don't try to record those voices in different positions in the room because you will get really nasty phase problems especially in a not acoustically treated room.
If you want i can mail you a list of microphones to check out. cheap or expensive..
Do you want to capture the ambience of the room ? Because you will need different mic placement for that one.
I assume water is somewhat a sound barrier
Actually is the other way around.