Yes: The Apple Thunderbolt to FireWire adapter works with Ensemble Firewire and the current Ensemble FW software release, found on Apogee’s website. There is no noticeable difference in quality or performance from using a built in FireWire port.
Note: This does not apply to Ensemble Thunderbolt. This adapter cannot be used to add Thunderbolt to a Firewire computer. You simply cannot use Ensemble Thunderbolt with a non-thunderbolt Mac.