Karyl Louwenaar and a new harpsichord build by local craftsmen Thomas and Barbara Wolf shared the honors at the Phillips Collection yesterday. Louwenaar's pristine technique allowed the runs of the Corente from Bach's E Minor Partita No. 6 to fly about with no apparent effort, and the thunderings of William Penn's "Fantasy" to roar with a marvelous momentum. The impressive-looking instrument answered every subtlety of her touch, its tone clear in every register and its action crisp and responsive.

Particularly attractive in this performance was Louwenaar's ability to integrate the ornamentation into the music of Scarlatti, Bach and Rameau.

The two contemporary pieces that closed the program were an interesting contrast with each other. Schiffman's "Ciaconna" employs a chaconne melody that is utterly devoid of the two requirements of such lines -- memorability and harmonic implication. His piece emerges as a structure without a purpose. Penn's "Fantasy," on the other hand, applies the forearm banging and elbow poking of some contemporary piano techniques to the harpsichord. The noise has a lot more character on that venerable instrument than it does on the piano, and it is a testimony to the art of the Wolfs that their instrument withstood the attack so sturdily.