Hmm. My audition with the imagine b was really short parang 10-15mins lang, and may katagalan na yun so take this with a grain of salt.
I found the Synchrony has a more refined treble. It makes the Imagine seem brighter although, both are designed by Paul Barton so one would assume that they are both designed to be flat. The Imagine B is something that you would consider warm-sounding already after all it was compared to a Harbeth by a Stereophile reviewer. The One B also has more bass, more punchy, and goes lower due to cabinet and driver size. The mids is cleaner with the Synchrony IMO. The Synchrony One B excels in imaging and depth perception too, I mean like crazy man!
BUT Ang nag trigger sakin bumili ng Synchrony One B was when I compared it to the Dynaudio Excite x16.