Old music, with less sweetener

British harpsichordist Richard Egarr is an early musiker who not only plays wonderfully, but also talks about music engagingly, as he did Friday at the Doheny Mansion, one of the stops in his first U.S. solo tour.

Take the thorny subject of the old tuning systems, in which the distances between notes were inconsistent, as opposed to what Egarr jokingly called today’s “communist system,” in which distances are relatively equal.

The theories and mathematics are frighteningly complex, but all Egarr had to do was strike two chords a half-step apart to make the point. The first, a C-major triad, was sweet and harmonious. The second, a C-sharp major triad, was unsettlingly sour -- to our ears, out of tune.

Now the interesting thing, Egarr showed, is that composers of the day knew how to use the “out-of-tune” notes expressively. Frescobaldi employed them for color or bite in his Toccata Settima and Cento Partite Sopra Passacaglii. Froberger used them in his Suite in C to accentuate his sorrow for the death of his patron Ferdinand IV.

A special tuning system lies behind Egarr’s recent fascinating Harmonia Mundi recording of Bach’s “Goldberg” Variations, but his larger goal there and throughout this recital was to show that the harpsichord is more closely related to the lute and harp than to the organ or later piano or fortepiano.

Hence his emphasis on allowing phrases to breathe and expand, whether in three contrasting Scarlatti sonatas, a sparkling Vivaldi Concerto in D as arranged by Bach, or Bach’s famed showpiece “Italian” Concerto.

Egarr also played Mozart’s Sonata No. 7 in C, K. 309. It was fun hearing the familiar opening flourish on a harpsichord instead of the more common piano or fortepiano and agreeable to hear how well the fast passages worked. But with the slower central movement, it became clear that the later instrument had called for a new kind of music, with greater dynamic contrasts and subtleties of touch than a harpsichord could provide.

Egarr played two instruments made by Curtis Berak -- a single-manual Italian harpsichord patterned after a 17th century model for works by Frescobaldi and Froberger, and a double-manual harpsichord after 18th century French models for Scarlatti, Vivaldi, Mozart and Bach.

Egarr’s single encore was a Ground in C minor by Purcell.