The first thing one notices about this disc is the attractive sound, rounded yet detailed; the second is that the playing of the orchestra is stylish; last but not least, the soloist's first entry tells us that he, too, is a fine player. Rainer Kussmaul's name was unknown to me, but a note on the jewel-case says that he is about to become leader of the Berlin Philharmonic Orchestra. He produces a lovely sound on what sounds like an excellent instrument, and phrases gracefully: altogether this is most enjoyable Haydn playing.
Not many string quartets play on period instruments, perhaps because the public for this music is not familiar with their sound, but also because much of the string quartet repertoire goes beyond the period that these instruments usually cover. The Festetics is one of the few top-rank quartets that does use such instruments, and has focused on the late 18th and early 19th century repertoire - Haydn, Schubert and Mozart - though they have also recorded works by other composers, such as Liszt.
There is a noticeable difference in the sound of this ensemble when comparing it with other quartets. The instruments are more trenchant, the sound is more limpid, and the texture less homogeneous. It is far easier for such an ensemble to create a sound of four instruments interacting, as opposed to a unitary sound that is a mixture of those instruments.
Ekaterina Derzhavina's name was new to me, but this 9-CD set of Haydn's complete piano sonatas should broaden her recognition considerably…Not surprisingly, since she plays all the sonatas, you can find better performances of some individual pieces, especially the later ones. But viewed as a survey of the entire corpus, her feel for Haydn's originality comes through brilliantly. Derzhavina is an exceptional artist, and rather magical.