Ghosthouse: I'm guessing since I have volume controls on both I can regulate spl from treble and bass. By trial and error at worst, I'd expect I could find optimal settings.
Tricky and unreliable. More than likely you will get variations in LF/HF balance as you try to reset levels. Besides, how will you know if they are set correctly especially as you change the level? Most dual VCs don't track accurately and two different VCs are likely to vary even more.
Does not seem to be worth the bother for any marginal improvement possible.
Kal