1. -The Ear -Beats
Physics
Mr. Berman

2. The Ear Auditory Nerve Pinna

3. Audible Frequencies Range of Greatest Ear Sensitivity 1,000-5,000Hz
Audible Range ,000Hz
Infrasonic below 20 Hz
Ultrasonic above 16,000Hz
Ultrasonic waves are used in sonar and in medicine to measure sizes and distances to obstacles.

4. Older people not as sensitive above 10,000Hz
Dogs hear up to 45,000Hz.
Cats, bats can hear up to 75,000 – 100,000Hz.

5. Beats
Beats occur when two sounds of very close frequency are heard at the same time.
Beat Frequency = | f2 - f1 |
Beat Pitch is the average of the two frequencies. 
Beat pitch = ½ ( f2 + f1 )

6. Beats
Simulation “Beats”

7. Beat Example What is the beats frequency and the beat pitch?
Two tuning forks sound simultaneously: one fork has a frequency of 256 hz and the other has a frequency of 260 hz. 
What is the beats frequency and the beat pitch?
Answer: 4beats/sec, Hz
4beats/sec Hz

8. Timbre : sound quality or tone color.
When two or more frequencies are played together:
If the sound is a pleasant sound: Consonance.
If the sound is an unpleasant sound:
Dissonance.