I have not heard the Sibelius but I did own a few single driver speakers, mainly using Lowther drivers. I think Bache's design of using a modified single driver to cover the range from 500 - 8,000hz, augmented by a super tweeter and woofers is a better way. The crossover is a cap for the tweeter and a coil for the woofers. The midrange has directly connected to the amps. It's more balanced than when I was using a Rel subwoofer with a pair of Rethms.