Why would be odd, complex or pricey? There are plenty of dongles that transmit from a USB port, the Avantree DG80 for example., why would it be any more difficult to do the reverse?
Thanks, that's a good suggestion, and would work for old bluetooth codecs. I've just checked whether it supports aptx, and unfortunately it doesn't, but I didn't mention that as a requirement in my question.
Is there such as thing as a Bluetooth receiver USB dongle that receives a Bluetooth audio transmission and emits it into a USB connection? It would be the opposite of an Avantree DG80, which receives a signal from a USB socket, and transmits it via Bluetooth. I've looked hard, and can't find...