Line level Cable selector for subwoofer

Here's a good quality, simple solution.

Niles PS-1

I use the Niles AXP-1 for my sub that does double duty for 2 Channel and HT. It may not look like much but when you see it and feel it in person it is really solidly built.

http://www.crutchfield.com/p_190AXP1/Niles-AXP-1.html?tp=1846

I realize this unit has 5 inputs and the OP only needs 2 but when I was looking for a source selector the AXP-1 was at a really good price and I didn't bother to look for anything else.

I'm going to try a SW4 Stereo Input Switching Control from Goldpoint. A bit pricey but seems well built