Transcript Slide 1
How does a String Make a Sound?
• When a string is made to vibrate by
rubbing or plucking, it communicates a
frequency to the surrounding air. When
these vibrations reach the tympanum
(eardrum), they are perceived as sound.
Without a medium (air or water), sound
cannot be propagated.
Rubber Band Shoe Box Demonstration
What is Resonance
• When one object vibrating at the same natural
frequency of a second object forces that second
object into vibrational motion.
• The word resonance comes from Latin and
means to "resound" - to sound out together with
a loud sound.
• Resonance only occurs when the first object is
vibrating at the natural frequency of the second
Tuning Fork Demo
The Overtone Series
First Harmonic- One Octave
Second Harmonic-One Octave + A Fifth
Third Harmonic-Two Octaves
Fourth Harmonic-Two Octaves + A Third
Fifth Harmonic- Two Octaves + Fifth
Sixth Harmonic – Two Octaves + Minor7th
Seventh Harmonic-Three Octaves
If the finger is placed at a whole fraction of the length of the string, the
vibration produces a note in harmony with the fundamental note. This
principle was discovered by Pythagoras already two thousand years ago.
• Pythagoras discovered that if one string vibrates with twice the
frequency of an identical string, we hear the higher frequency as one
octave higher in pitch than the lower frequency
• The vibrating systems on most musical instruments are made up of
two or more vibrating systems working together to produce sounds
loud enough to be heard by the human ear.
• Examples of instruments with two or more vibrating systems include
the membranes of leather stretched across the tensioning loop of a
drumhead, the strings and the sounding board of a piano.
• Other examples are the strings and the body of a guitar or violin, or
the reed and air column of the air column of the clarinet.
Demo On Piano
How Does a String Change Pitch?
Bass Viol/ Double Bass
String instruments of other cultures