If you go with some link using the RFM12’s then you going to need a ucontroller at each end. I believe that’s the only reasonable way to configure them and to get the (music) data to them and from them. What I’d do is first figure out where the music resides and how it gets to the speakers. Leave out the specific part selection at this time and think functions.
ie - If the music resides as files on your PC then it’s already in digital form. Seems easiest to perhaps keep it that way and send it, with minimal processing, as a bit stream to a receiver at the speakers. Once there you have to decide if you need to send it digitally to the speakers (will you have USB speakers ?) or convert it to analog to be feed into … what ? Will the speakers be powered (like a set of PC speakers) or will you need to have a separate audio power amp that’s then wired to the speakers. That seems to defeat the whole purpose. Will you have 1 RF receiver + decoder/controller that is wired to 2 (or more ?) speakers or will each speaker have it’s own receiver built into it, so only a line cord is needed ? That’s certainly neater, less wires, but it’s more receivers and decoder/controllers. If the data comes out of your receiver in digital form, how will it get (eventually) to a voltage with enough “umpf” to drive a speaker ? Will the data be raw audio samples of MPEG encoded ?
So where’s the transmitter going to be located ? How will data from your PC get to it ? Are you going to plug it into a USB port and send data to it ? What software on the PC will do that ? If you do that, you’ll need some interface logic between the RF transmitter and the USB port. What format is the data coming across and what format will your RF link support ? If you have 2 receivers, one in each speaker, will you need 2 transmitters or will you share the one ?
What word length and sample rate will be needed to get the quality of sound you desire ? What encoding is needed to get that data reasonably intact across the RF link ? If there’s interference how will your system cope with it ? Then you can ask what bit rate is needed. Are all the files on your PC in the format you need ? Are they all in the same format (sample rate, word length, etc) ? If not, where will the conversion be done ? In software on your PC or in the interface logic that you will need (in any case) to convert the USB to something your RF transmitter can understand ?
You might be able to use the WiFi transceiver you have in your PC. I don’t know how to advise you on doing that other than to say I believe it can be done. That’s a whole 'nother set of standards you’d have to learn (to do WiFi).
Then again you could use the PC’s headphone output and come up with an analog RF transmitter. I don’t think you’ll find one in SF’s part bin though. And then the receiver(s) need to demodulate the RF are different than you’ll find in that parts bin too. If you do that then it’s probably best to keep it all analog and that means a simpler (no D/A) audio power amp.
My point is you need to think about the big picture first, scheme up alternate ways of accomplishing the task and their pros and cons. Then think about the parts needed to do those functions. You’ll then no doubt have to revisit the pros and cons based on what’s available and their costs and what you know how to do.
This isn’t something that can be slapped together in a weekend but if you do it you’ll definitely learn a lot.
