If you are using 80Hz crossovers across the board, I'd suggest playing with those settings a bit. I couldn't find a lot on your Quad's, but I did find some info on both at tnt-audio - the 11L apparently starts to roll of sharply at 80Hz, while the 12L goes down to 70Hz before starting to roll off more gradually. You've got the ability to use a different crossover both at the ICBM and in the 1070's digital bass management - you might give 100Hz or even 120Hz a whirl just for fun.