Pulled my Mission 705's out of the loft today and wired them up. 1 of them sounded great but the other was a bit dull. Initially i thought the tweeter was blown but looks like it might be the crossover. These speakers are probably 15 years old. I have a full set 705's 704's 701's and 2 centres as well as 2 pairs of 70ds. I think its going to be hard to find replacement crossovers for these. Can they be replaced with off the shelf crossovers ??