It's not wireless, and I'm so sorry but I know nothing about Bluetooth! I just plug my iPod or iPhone into it and listen that way... A tablet should work if it has the same connection.... I'll check that and let you know ASAP! :)
I'm not sure how to answer about how loud they get... Not to "blasting" level, but I can hear it clearly over the noise of bathroom fan and shower when I used it in the bathroom :) had to turn it down once the background noise was gone... Loud enough to fill a room, but not gonna hurt any ears. They are relatively small (3" diameter), and the whole thing is 5" long 4" tall, and 4" wide. Hope this helps everyone interested... The sound is clear, even when my iPod is at max volume.