Apollo’s Cabinet are a period-performance group, but with a different angle from most: like a slightly less unbuttoned version of the Norway-based Barokksolistene, they are concerned more with storytelling than historical accuracy. Their debut CD is an engaging travelogue. Alexander Armstrong narrates from the diary entries of Charles Burney, the august historian who took two European tours in the early 1770s and made it his business to record the musical state of the continent.