Understanding the Resonance of String Instruments

The body of a string instrument is a resonating box. If it were made of solid wood instead of being hollow, the sound of the bowed string would be small and thin.

The Role of the Bridge

The bridge transmits the vibrations down into the resonating box, where they are amplified.

• Using your knuckles, gently tap the body.

  • Listen to the sound of each tap resonating through the instrument. This is a nice thing to do.

• Using your fingernail, scratch the top of the bridge lightly between the strings and listen to how the sound is amplified.

  • If you make the same scratching movement on something solid, like a tabletop, you can't hear anything.

You can hear this background resonance in every note you play.

Playing and Listening

1. Play a short note and listen to the ring.

   • You can hear how the note continues to ring on after the end of the bow stroke.

2. The Question: What happens to that ring during a longer note?

   • If you listen carefully, you can hear two distinct sounds:
     • The sound of the fundamental note
     • A continuous background ring, which is like a distinct note ringing on its own.

Many players listen only to the fundamental sound, the sound of the string vibrating from the contact with the rosin bow hair.

• The moment they start to focus on the background echo as well, an entirely new quality comes into the playing.

Practical Tips

• Use all the bow.
• Tim, are you touching the D string? Because I can hear it really ringing.
• Let's hear just the A string.
  • That's good.

But, Tim, I'll tell you something else.

• There are two distinctly different sounds you can listen to:
  • One is the principal note, the fundamental note, the string vibrating.
    • There's all that sound of the actual beginning of the note.
  • But there's another sound, which is the resonance, the echo.
    • This is a resonating box. You need to make it really resonate.

So this time, really focus on not the principal sound, the fundamental sound, but the background ring. See what happens.

Very good. Great. So interesting. You know, you do that, and although you weren't trying to, I can immediately see the string going so much wider in amplitude.

Excellent.