Joseph Johnson, principal cellist of the Toronto Symphony Orchestra since 2009, once said the cello has “the same range as the human voice” — an observation that resonates with his summertime role as principal cellist of the Santa Fe Opera Orchestra. Johnson steps outside his orchestra roles this weekend in a pair of solo concerts that will test his instrumental voice. Both performances — the first at 10:30 a.m. on Saturday, July 13, at SITE Santa Fe (1606 Paseo de Peralta), and the second at 10:30 a.m. on Sunday, July 14, at Las Puertas Event Center (1512 1st St. NW, Albuquerque) — will air J.S. Bach’s Suite No. 4 in E-flat major, composed some 300 years ago, and Benjamin Britten’s Suite No. 1 for Unaccompanied Cello, Op. 72, composed in 1964. Tickets ($15, $9 for students and those under 30, $5 for children) are available at chatterabq.org/boxoffice.