# How come a string of a musical instrument produces sound when it looks like a transverse wave instead of a longitudinal wave?

As you may probably tell, I am still new to physics and in school, we're learning about waves right now. When I watched how strings vibrate, they looked like transverse wave.

So, my initial thought was all waves looked like transverse wave. But then, after learning the chapter about waves, I found out that sound is actually longitudinal wave. Or is it all the time?

How come strings vibrate like transverse wave but still produce sound?

• A transversely vibrating drumhead can push the air unleashing longitudinal compression waves in it. Jan 13, 2018 at 14:54

In string instruments, the bridge will transfer the transverse motion of the string to a soundboard. This then moves to put the air above and below it in motion, causing a longitudinal wave.

The soundboard is also often part of a resonance cavity. For example, the body of an acoustic guitar is a Helmholtz resonator, where much of the sound comes from air moving in and out through the hole.

• So does that mean when the energy is transferred through the solid, it is in transverse motion, but when the energy goes to gas, it changes to longitudinal wave? Jan 14, 2018 at 3:39
• @AmmarSarif Terms like "transverse" and "longitudinal" are relative to the direction of propagation of the wave. But there is not really a wave in the soundboard or in the Helmholtz resonator. Or in a loudspeaker..
– user137289
Jan 14, 2018 at 10:39