Add wireless speakers to Philips BTM2180/37 stereo

Solution
You can attach a speaker to line level converter (with level control) in parallel with the speakers that are already connected.
http://www.crutchfield.com/p_142LOC80/Scosche-LOC80.html
This gives you a connection for a wireless audio transmitter (any kind). The only downside is that the volume control of the micro system also controls the input to the transmitter. The level control in the converter gives you some control of the how much input the transmitter gets.
You can attach a speaker to line level converter (with level control) in parallel with the speakers that are already connected.
http://www.crutchfield.com/p_142LOC80/Scosche-LOC80.html
This gives you a connection for a wireless audio transmitter (any kind). The only downside is that the volume control of the micro system also controls the input to the transmitter. The level control in the converter gives you some control of the how much input the transmitter gets.
 
Solution