Q:

How can I use the output of a wireless mic reciever as a wireless monitor and get audio on both sides of my headphones?

I referred to this Q&A, but I'm still confused:
Stereo and mono cables and jacks? What happens when you cross them?
I have this wireless lav set:
http://www.amazon.com/Sennheiser-EW-112P-G3-A-omni-directional/dp/B002CWQTXG/ref=pd_sxp_grid_pt_0_2
I'm wanting to use the transmitter to transmit an aux from a mixing console and use the receiver to plug my headphones into. I want the mono signal to go to both sides of my headphones (plugging stereo plug into mono jack).
How do I achieve this?

A:

You have a few options, 
1) you can buy a 1/8 or 1/4 inch headphone jack and short the L R connections together since (in an unbalanced situation (most regular headphones)) they share a common ground. Keep in mind you will be driving twice the load from the same source which will effect the output.    
2) You can buy a headphone amplifier that has a mono input function. Just look around they are out there. If you are talking about the signal from line out of the receiver you will need a headphone amp anyway. 
3) You can try and sell/trade the system for a wireless monitoring system designed for this task. 

