Getting ready to pull the string on a series of monitors for tracking and mixing. Kinda sold on these from TC Electronics. Active studio montors BM5A, BM6A and BM15A's. Using the 6's for mixing and 15 and 5's for tracking. Trying to get a surround thing for tracking. Probably a little over kill. Thinking of a Mackie Sub to try and keep costs down. About $500.00 diff in price for the sub from TC. Figured I check with the pros for some feedback. Kinda pricey, so any advice would help.