I recently used my zoom h1n and although its set to stereo, it was hooked up to a mixer for an event and the audio came out as mono. Is there anything i can do to get the audio to come out of both left and right headphones? Im on a mac btw…thanks
And you used it with Cubase, if so - set up the outputs correctly. Otherwise contact Zoom. In any case provide some useful information… 
If the audio is only coming from a single speaker, press F4 and check if your outputs are stereo. The “Presets” menu at the top of this window will allow you to setup your outputs easily.
If you recorded to a stereo file but only one of the channels has sound (double click the recording in Cubase to check), create a mono Audio Track and move your recording to it. The audio will automatically be centered.