Horsehair’s directional grip enables sustained bowed-string notes

Evidence

The sound source that results from bowing a string is periodic, and a continuous note can be produced while the bow travels in one direction. A bow supports many strands of hair, traditionally horsehair. Hair tends to grip in one direction but not in the other. This can be demonstrated with your own hair. Support the end of one hair firmly with one hand, and then grip the hair in the middle with the thumb and index finger of the other hand and slide that hand up and down the hair. You should feel the way the hair grips in one direction but slides easily in the other. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1104

Categorization

• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1104
• XREF: connects to: Bowed string motion is a stick-slip effect producing a sawtooth wave — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 670; A bowed string alternates constant-velocity grip with rapid snapback motion; Bow hairs are laid half in each direction so both strokes grip equally (+1 more)

Broader Connections

• A bowed string alternates constant-velocity grip with rapid snapback motion #expands (0.85)
• Bow hairs are laid half in each direction so both strokes grip equally #expands (0.80)
• A bowed string vibrates as a traveling kink, not as smooth standing waves #expands (0.78)