audiovox hrdv700

I have an '02 Suburban I recently bought used and it came with the Audiovox Dual Headrest DVD (HRDV700) system installed. We tested it before we bought the vehicle and I thought it was working correctly. I admit we were rushed though and I didn't pay too much attention to it. Anyway the headphones are not Audiovox and they are not dual channel. The problem we are having is not being able to pick up the individual pod signals. When we have two DVD's playing we are only able to pick up the signal from M1 (M2 sometimes has a fair bit of static also).

I did a search on here and found one thread that made mention of the dual channel headphones but the original poster did not post back to say if he was successful or not. I assumed that the IR transmitter in M2 went bad and we were picking up the signal from M1 but since it was "far" away that is why it wasn't a good signal and we ended up with static. I also assumed the "broadcast" distance was fairly short.  I don't know how valid these assumptions are though and I can't find any information on Audiovox's website regarding the distance the IR headphones are good to. I spoke to someone who said some of the Eclipse dual units have an option in the set up screen where you can specify at what frequency each unit broadcasts at. I don't see anything like that in the set up screens for our unit.

Does anyone know if it possible to use single channel headphones with this set up or is the dual channel required?

Thanks in advance,

Phil

I just double checked and the model number is NOT HRDV700, it is HR9000.