1. Some Remarks About Beats
February 27, 2009
Look up beats in the textbook or in Measured Tones.

2. Beats
When two tones f1 and f2 sound together, the resulting combination can sound good, bad or even horrible.
If f1 and f2 are far apart, they may sound like two separate tones.
If they are an octave apart they will sound just fine.
If they are very close to each other, the sound of audio beats will be heard.

3. Example: f2-f1=2 Hz.

4. Adding Two Tones
Tone #1
Tone #2
Beat Period

5. N Peaks
N +1 Peaks

6. N Peaks
Tone-1
Tone-2
N +1 Peaks
Some
Algebra

7. The beat frequency is the difference between the frequencies

8. Two frequencies, 440 Hz. And 443 Hz. beat together
Two frequencies, 440 Hz. And 443 Hz. beat together. What is the beat frequency?

9. It could be 442 (442-440=2) It could be 438 (440-438=2)
A tuning fork has been damaged and its frequency slightly changed. What could its altered frequency be if it produces two beats per second with a tuning fork that is known to vibrate at 440 Hz?
It could be 442 ( =2)
It could be 438 ( =2)