^The input impedance of the FPB 250 M's is passive friendly, but the sensitivity might be a concern at 2.4 V for full power output. You paid for that power, might as well get what you paid for. It might behoove you to make sure all your sources are up to that, and don't forget to consider your interconnects too. CD red book calls for 2 V, though many DACs put out more. Tuners, etc. are not likely to be fully up to it.