connecting gps, radar audio to headphones

That was the only cable available..so I also purchased adapters.

http://www.cablestogo.com/product.asp?cat%5fid=102&sku=03195

Im using isolator earphones that for use on my motobike. 

ok   and the gps and radar detector have what kind of jack?

The gps has a stereo 3.5mm jack and the radar a mono 3.5mm jack.

Oh ok this wont be hard at all. youll need one  8 foot mono cord which will plug into the mono jack for the radar. Youll cut the jack off the other end. There will be 1 wire inside.

You will need one 8 foot stereo cord that will plug into the gps. You will cut the jack off the other end. There will be 2 wires. You will splice those wires together.

You will need another stereo cord (length youll need to determine). You will cut off 1 jack. Leave the other one alone. The cut end will have 2 wires. Splice one into the mono cord that you had cut earlier. Splice the other wire into the stereo cord you had cut earlier. On the other end youll need a 3.5" 2 female connecter. Youll plug the one female end into the headphones and the other into the "length youll need to determine" cord. Now your gps will come out one headphone, and the radar will come out the other side. Understand?

No because your one unit gives out only to a right speaker, your other gives out to both right and left. So when you get to the Y adapter, it mixes the right's from both units together. Thats why they blend together. The setup I gave you takes stereo unit and makes it a mono but the difference is that I keep both units seperate.  Its the same thing if you had 2 mono units and used a Y adapter. You would have blended audio coming out of 1 head phone speaker. understand? If you want me to draw it up to explane it more, I can.