Let the hive mind of Engadget get that for you.
"I am looking for a device that will stream sound from one source to several recipients. For example, I want to stream sound from my TV or stereo to my phone or MP3 player that has radio and Bluetooth capabilities. I have looked into radio transmitters and they seem like a decent choice, but I can't find one that uses external power (USB or from the plug) and I would want one with a transmit range of around 50 meters. Thanks!"
http://forumz.tomshardware.com/network/modules.php?name=Forums&file=viewtopic&p=83416#83416
I've tested a lot of these systems but unfortunately not the Infrant units. I am not using the Synology CS-406:
http://www.tomsnetworking.com/2006/09/15/synology_cs406_cube_station_nas/