The traditional cello has four strings: A, D, G and C. Each string is tuned a perfect fifth from the others (or seven half-steps apart). From the lowest (C) to the highest (A) open string, it covers nearly two octaves. From open C to the end of the fingerboard on the A, the cello’s range is approximately five and one-half octaves. Many of the notes can be played in multiple places on the instrument.
The highest, or first string on the cello is A. Based on current trends of tuning to A440, the cello A sounds at 220 Hz or A3 on the piano keyboard. When you buy a cello A String, you might see it labeled as “I” (Roman Numeral) or “La,” referring to the solfege (Do Re Mi) or European musical name. The open A String is notated in the bass clef as the top line. You may also see it as the middle line in the tenor clef, or the second ledger line below the staff in treble clef.
The second string, a fifth down from A, is D. It sounds at approximately 146.8 Hz or D3 on the piano. The D String is often labeled “II” or “Re.” Open D in the bass clef is the middle line. In tenor clef, open D is the bottom line.
The third string is the G String. Another fifth down from D, the G String is tuned to 98 Hz or G2 on the piano. Commonly labeled “III” or “Sol.” This is the bottom line of the bass clef staff.
The fourth string, C, is tuned to 65.4 Hz or C2 on the piano. This is the lowest note on the cello. C is also frequently labeled as “IV” or “Do.” Open C is the second ledger line below the bass clef staff.
The cello uses three clefs to read music: Bass, Tenor and Treble Clef.
Baroque or Electric cello, and certain pieces in the repertoire may require a fifth string (E), which would sound another fifth above the A string. There are also pieces which ask the cellist to tune one or more strings up or down to fit the hand better and tonality of the piece better. One example of this piece is Kodaly’s Sonata for Solo Cello where the C and G Strings are tunded down one half-step to reach a B and an F-Sharp. You can hear this in the first chord of the piece.