I have a problem with my hardware for an experiment I am preparing to run. I have bought a pair of research grade etymotic earphones for circa £500. They end up in two 6.5mm jacks. I need to plug them into the 3.5mm headphone input on my MacBook Pro laptop using an adaptor.
I have modified the sounds (1000 sounds) in MatLab so that 500 sounds have reduced volume on the Right, and 500 reduced volume on the Left. I am studying the interaction between falling-asleep-to-losing-consciousness and various sounds being played on the left and on the right ear. When I play the sounds through my laptop's speakers, I can clearly hear the sounds coming from the left and the right speakers as they should. When I plug in the 6.5mm jacks to the macbook pro headphone through an 6.5 to 3.5mm adapter and I hear the sound via the headphone, the separation between the left and the right volume modifications is lost.
Its a big issue and has stopped my research dead. I am not sure how to proceed.
Any ideas please?