plum pal, I don't have any direct experience except one of the pals I ride with regularly during our lunch rides carries a bluetooth speaker.It's weather-proof and loud once he turns up the volume. But ersonally, I don't like the form factor., it's pretty big. He bought it from Best Buy a while ago and I think he paid too much for it. There are probably better options out there now. A quick google search:
https://wiki.ezvid.com/best-bike-spe...FUdlfgodYYAAng
https://www.amazon.com/exec/obidos/A...ikespeakers-20