You may get more knowledgable answers but we wanted to accomplish this with my husband's favorite 2 radio stations outside. Hewanted really good sound system ended up buying the Bose outdoor speaker you can pick up and take outside or pretty much anywhere....not to be confused with their set of 2 speakers that are Wired. The blu tooth setup/pairing was easy. There are other wireless speakers that do the same thru Blu tooth but if you are using a regular stereo and cd player vs yr computer,I do not know if this is possible

Any "wireless" speaker needs power (unless it is battery powered). Sometimes it's more difficult to install the outlets for the power than to just run the wires.

A couple places to find this kind of equipment: Parts Express and Crutchfield. Both have good online catalogues.

"Bose" and 'really good sound' do not really go together for me, haha.