Yeah I should have explained that a bit better. Try this...
Make a copy for the Right channel also. You could use a TL074 instead of 2 072's. For Vref you could either
A...supply with 18 volts and make a reference voltage with dividers
B...Use charge pump to supply +/-9v where 0v (ground) becomes vref.
I'd go for option B as I'd rather have a bunch of 9V supplies kicking about than "that one supply that'll only work with that splitter thingy"
As with all things...I recommend breadboarding first. The input cap could probably go as low as 10nF
Hope that helps