I normally don't post in forums but I wanted to share this solution for what I think is a common problem for dance studios. Problem: You want to practice with your partner but the sound system is being used by someone else. Sure, you or your partner can keep count verbally, but this isn't the same as dancing to the music and can't practice "musicality". Being a beginner dancer and also a technology enthusiast, I couldn't help but try to find an elegant way to have two dancers listen to their own music regardless of what music is being played on the studio's sound system. Without getting too much into the technology, my solution relies on a Bluetooth transmitter that can transmit to two headsets simultaneously. There are two transmitters I know of that do this but I am sure there are more. Kokkia's A10m transmitter and GoGroove's BlueSense TRM. The key specifications to look out for are BlueTooth 2.1 + EDR and A2DP (they usually are implemented together). Additionally, seek for it's ability to "multistream" and to stream to two devices simultaneously. If you can download or view the transmitter's user manual, even better, so you can confirm this feature. I purchased the Kokkia A10m and paired this with two headsets and it worked flawlessly. You can use this with any sound source that uses a 3.5 mm stereo jack which means just about any smartphone or portable media device (e.g. iPods). As long as your Bluetooth headsets support A2DP audio streaming (check your manual or just try it), you and your partner can dance to the same music wirelessly. I'm pretty excited that my partner and I will be able to practice on a crowded dance floor with our own music. I think that studios that book simultaneous lessons on the same dance floor might want to really look into implementing this. Has anyone run into this problem? If so, how do you solve it?
I tried a similar solution to this problem a few years ago. I wore a MP3 player and listened directly with an earpiece. My partner listened via a bluetooth link connected to a second output on the MP3. This did not work well because the bluetooth processing introduced a significant delay to the signal heard by my partner. I assume your A2DP streaming will give an almost identical delay for both partners so that should not be a problem.
My solution was to use an analogue radio microphone based link instead of the digital bluetooth. That also allowed our teacher to have the MP3 player while my partner and I both had radio mic receivers. An expensive solution but I happened to have the radio mics already.