The Logitech Wireless Bluetooth Speaker Adapter will connect to any
speakers that can facilitate a standard analogue RCA or 3.5 mm jacks.
Transforms any speakers into a wireless sound system for your bluetooth-enabled
computer, smartphone or tablet!
Eu imagino que outros fabricantes tenham produtos similares.
Quase certamente requer monitores ativos (ou um amplificador Hi-Fi). Transmitir um sinal de áudio é uma coisa, transmitir centenas de watts de potência para alto-falantes passivos é feito usando fios.
Aqui está outro
The Model 1540 turns your speakers into wireless speakers. No more
running long speaker cables. Set up your home theater rear speakers
without a big cabling project.
The transmitter will send the music at 5.8 GHz up to 100 feet. You
will enjoy better than CD quality with uncompressed digital wireless
audio. The receiver has a stereo speaker amplifier built in and
connects directly to any passive loudspeaker. The built-in amplifier
delivers the efficiency of conventional class-D amplifiers while at
the same time delivering far lower audio distortion.