Only about 4% of bowing energy becomes audible sound

Evidence

The power that goes into bowing a violin, however, is about 150 mW, so only about 4% of the energy supplied to the violin winds up as sound. The rest is dissipated mainly as friction at the bow, vibrational energy absorbed directly by the player through the violin, and internal friction within the construction material. — Eric J. Heller, Why You Hear What You Hear- An…, 1808

Categorization

• XREF: Directly connects to the broader transduction-efficiency puzzle of why instruments are so inefficient at radiating sound.