i saw too late your double- posting in this and the DIYHifisupply- forum so i copy my answer from Brian`s forum:
Hello Jean- Francois,
i recommend to use an adaptor from balanced to RCA so you don`t need a Y- adaptor in the main signal- path. I prefer the RCA- connection over the poweramp- connection (most of my customers, too) but there are some who claim that they like the speaker- connection better. When you try the RCA- connection be shure that the phase- adjustment is 100%, this is essential for a good result. To set the phase shut down one of the Titans, lift the crossover- frequency and volume of the other one and tune the phase- knob until there are maximum fat and boomy basses at LISTENING- position. Then go down again with volume and crossover to your normal level, set the second Titan exactly like the first - ready. Only when the phase is correct there is absolutely no "break" between the woofers and the baffles! Tip: Let the woofers play for two weeks before you tune the Titans, the woofers become much louder in this time because of the burn- in. For your setup i recommend to try the Magic Twins filterelements.
Regards
Robert Bastani