1. The principle behind the design of musical instruments
♫ Resonance ♫
The principle behind the design of musical instruments

2. Applications of Resonance
When does it occur?
What is Resonance?

3. Applications of Resonance
When does it occur?
What is Resonance?
Standing Wave
Big Amplitude

4. Applications of Resonance
When does it occur?
When the system is being driven at its natural frequency
What is Resonance?
Standing Wave
Big Amplitude

5. Applications of Resonance
Natural Frequency
Driving Frequency
What’s the difference?

6. Applications of Resonance
Natural Frequency
Driving Frequency

7. Fixed String Natural Frequency (n v / 2 L) = Driving Frequency
 RESONANCE
Natural Frequency  Driving Frequency
 NO RESONANCE

8. Resonance: Good or Bad? GOOD Music Electronics (sometimes) NMR / MRI
(Nuclear Magnetic Resonance – used in medicine)
BAD
Earthquakes
Car Engines
Building vibrations (Civil engineers try to avoid resonance)

9. Medieval Riddle
From 1511:
“What thing is it, the less it is, the more it is dread?”

10. BAD RESONANCE Lessons from the Prussian Army
Modern disasters of resonance:
1) Collapse of suspension bridge in France in 1850
2) Washington State: “Galloping Gertie”

11. Flame Tube AKA Rubens Tube
Fill pipe with propane or other flammable gas
Turn on Speaker
Set on Fire
Bridgewater
College
Flame Tube
Dec 2011

12. Exciting Resonance Applications
Breaking Glass with your voice
Vocal Coach Jaime Vendera Shatters Glass # 85
Youtube comment: “You know he's wearing glasses because one of the 84
previous glasses stuck him in the eye.”

13. MICROWAVE OVEN HYPOTHESIS
Resonance or Not?
Microwave Oven:
1) Microwaves
2) Water-based food (with some natural frequency)

14. RESONANCE IN MUSIC Resonance Cavities in string instruments
Does every violin need to look like this:
Stradivarius

15. RESONANCE IN MUSIC Electric violins & guitars don’t need to resonate
Therefore, they can have funny shapes

16. IS THERE SOMETHING SPECIAL ABOUT STRADIVARIUS VIOLINS?
Digression
The Great Stradivarius Debate:
Truth or Hype?
IS THERE SOMETHING SPECIAL ABOUT STRADIVARIUS VIOLINS?

17. The Great Stradivarius Debate
Digression
The Great Stradivarius Debate

18. HOLOGRAPHIC INTERFEROMETRY
Analyzing vibrations of string instrument bodies
HOLOGRAPHIC INTERFEROMETRY

19. Bass (two columns from low to high frequency) Resonating Sand Video
Analyzing vibrations of string instrument bodies
Bass (two columns from low to high frequency) Resonating Sand Video

20. What drives the instrument?
String instruments (eg, Violin)
Wind instruments
Brass Instruments

21. What drives the instrument?
Violin – Bow
Wind instruments – Reed
Brass Instruments – lips must vibrate
How does the reed (or your lips) “know” which frequency to vibrate at?

22. Summary What must be true for resonance to occur?
How do you know when it is occuring?