Performing Beethoven piano concertos with chamber-group accompaniment is a much less self-indulgent idea than one might think -- the arrangements here date back to the nineteenth century, and one of them, that of the Piano Concerto No. 4 in G major, Op. 58, was apparently performed by Beethoven himself at the keyboard. Such arrangements filled a need in a time when a symphony orchestra was something that could be put together only by a large, prosperous city or noble house. Music of the nineteenth century was dominated by transcriptions and arrangements to a greater degree than is generally realized, and the phenomenon provided a sort of counterpoint to the notion of the solitary creator driven by the imperative of expression to create unique masterpieces.
Of course, an authentic performance of an arrangement from the first decade of the nineteenth century wouldn't use a modern piano; it wasn't until a decade after the Piano Concerto No. 4 that Beethoven acquired an instrument resembling the grand piano of today. Pianist Heidrun Holtmann and the Concertino München (a string quintet of three violins, viola, and cello) are sensitive to the issues involved here. In situations where Beethoven aimed toward maximum contrast between piano and orchestra, such as in the slow movement of the Piano Concerto No. 4, the quintet uses articulation to create different kinds of contrast. Holtmann reins in her piano. But it still overwhelms the string quintet somewhat -- not in volume so much as in resonance. It just doesn't quite fit with the small string group. Still, many libraries should add this odd bit of Beethoveniana to their collections even if the market for it among general listeners will be limited to curiosity seekers.