I'm looking for basically the opposite of a splitter. I recently bought a Roland OctaCapture interface, and it'd be great if my bandmates and I could plug our headphones into each of the 5 pairs of output channels (10 in total). These channels are all mono, so I'd need to combine two channels to get stereo through the headphones.
Am I doing this completely wrong, or is there a product that takes two individual stereo channels and combines them into one?
I'm looking for two male connectors to plug into the interface, combining into one female connector into which I'll plug my headphones.