Double stop

A double stop, in music terminology, is where a musician plays two notes simultaneously on a stringed instrument, which is easily achieved on a violin for example, but also on cello or viola or other stringed instrument. In performing a double stop, two separate strings are used (stopped by the fingers), and bowed simultaneously.

Likewise the triple stop and quadruple stop. Collectively, double, triple and quadruple stopping is called multiple stopping.

The style of bow used until around the end of the 18th century, particularly in Germany, had the wood curved outwards, which made it somewhat easier to play three notes at the same time. However, most treatises written around the time make it clear that composers did not expect three notes to be played at once, even though the notes may be written in a way as to suggest this, and playing four notes at once is almost impossible even with older bows. The normal way of playing three or four note chords is to briefly sound the lower notes and allow them to ring while the bow plays the upper notes. This gives the illusion of a true triple or quadruple stop.

A twentieth century invention by Emil Telmányi called the Bach bow makes use of a system of levers to temporarily slacken the bow hair and allow sustained three or four note chords; this design has no historical precedent and is less authentic than an ordinary modern bow for playing baroque (or any other) music.

In addition to the style of bow, the curvature of the bridge is an important factor in the ease of multiple stopping. On most classical instruments, the bridge is curved enough to make it difficult to play three strings at once, but on some violins the bridge is shaved down until almost flat, making it far easier to triple stop, as well as to alternate double stopping on different pairs of strings (D-A to A-E for example). The compensating disadvantage is that more skill is needed to avoid playing a double stop when none is called for.