♫ resonance ♫ the principle behind the design of musical instruments
TRANSCRIPT
♫ ♫ Resonance ♫Resonance ♫
The principle behind the design of The principle behind the design of musical instrumentsmusical instruments
What is What is Resonance? Resonance?
When does it When does it occur?occur?
Applications of ResonanceApplications of Resonance
What is What is Resonance? Resonance?
• Standing WaveStanding Wave• Big AmplitudeBig Amplitude
When does it When does it occur?occur?
Applications of ResonanceApplications of Resonance
What is What is Resonance? Resonance?
• Standing WaveStanding Wave• Big AmplitudeBig Amplitude
When does it When does it occur?occur?
• When the system When the system is being driven at is being driven at its natural its natural frequencyfrequency
Applications of ResonanceApplications of Resonance
Applications of ResonanceApplications of Resonance
Natural Frequency Natural Frequency Driving FrequencyDriving Frequency
What’s the difference?
Applications of ResonanceApplications of Resonance
Natural Frequency Natural Frequency Driving FrequencyDriving Frequency
Fixed StringFixed String
Natural Frequency (n v / 2 L) = Driving Frequency Natural Frequency (n v / 2 L) = Driving Frequency
RESONANCERESONANCE
Natural Frequency Natural Frequency Driving Frequency Driving Frequency
NO RESONANCENO RESONANCE
Resonance: Good or Bad?Resonance: Good or Bad?
GOODGOODMusicMusicElectronics Electronics (sometimes)(sometimes)NMR / MRINMR / MRI
(Nuclear Magnetic (Nuclear Magnetic Resonance – used in Resonance – used in medicine)medicine)
BADBADEarthquakesEarthquakesCar EnginesCar EnginesBuilding vibrations Building vibrations (Civil engineers try to (Civil engineers try to avoid resonance) avoid resonance)
Medieval RiddleMedieval Riddle
From 1511:From 1511:
““What thing is it, the less it is, the more it is What thing is it, the less it is, the more it is dread?”dread?”
BAD RESONANCEBAD RESONANCE
Lessons from the Lessons from the Prussian ArmyPrussian Army
Modern disasters Modern disasters of resonance:of resonance:
1) Collapse of 1) Collapse of suspension bridge suspension bridge in France in 1850in France in 1850
2) Washington State: 2) Washington State: “Galloping Gertie”“Galloping Gertie”
Flame Tube Flame Tube AKA Rubens TubeAKA Rubens Tube
1.1. Fill pipe with propane or other flammable Fill pipe with propane or other flammable gasgas
2.2. Turn on SpeakerTurn on Speaker
3.3. Set on FireSet on Fire
Bridgewater Bridgewater
College College
Flame TubeFlame Tube
Dec 2011Dec 2011
Exciting Resonance Exciting Resonance ApplicationsApplications
Breaking Glass with your voiceBreaking 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.”
MICROWAVE OVEN MICROWAVE OVEN HYPOTHESIS HYPOTHESIS
Resonance or Not?Resonance or Not?
Microwave Oven: 1) Microwaves2) Water-based food (with some natural frequency)
RESONANCE IN MUSICRESONANCE IN MUSICResonance Cavities in string instrumentsResonance Cavities in string instrumentsDoes every violin need to look like this:Does every violin need to look like this:
Stradivarius
RESONANCE IN MUSICRESONANCE IN MUSIC
Electric violins & guitars don’t need to resonateElectric violins & guitars don’t need to resonate
Therefore, they can have funny shapesTherefore, they can have funny shapes
IS THERE SOMETHING SPECIAL IS THERE SOMETHING SPECIAL ABOUT STRADIVARIUS VIOLINS?ABOUT STRADIVARIUS VIOLINS?
DigressionDigression
The Great Stradivarius Debate:
Truth or Hype?
DigressionDigression
The Great Stradivarius Debate
HOLOGRAPHIC HOLOGRAPHIC INTERFEROMETRYINTERFEROMETRY
Analyzing vibrations of string instrument Analyzing vibrations of string instrument bodiesbodies
BASSBASS
(TWO COLUMNS (TWO COLUMNS FROM LOW TO FROM LOW TO HIGH FREQUENCY)HIGH FREQUENCY)
RESONATING SAND RESONATING SAND VIDEOVIDEO
Analyzing vibrations of string instrument bodies
WHAT DRIVES THE INSTRUMENT?WHAT DRIVES THE INSTRUMENT?
String instruments (eg, Violin) String instruments (eg, Violin)
Wind instrumentsWind instruments
Brass InstrumentsBrass Instruments
WHAT DRIVES THE INSTRUMENT?WHAT DRIVES THE INSTRUMENT?
Violin – BowViolin – Bow
Wind instruments Wind instruments – Reed– Reed
Brass Instruments – lips must vibrateBrass Instruments – lips must vibrate
How does the reed (or your lips) “know” which How does the reed (or your lips) “know” which frequency to vibrate at?frequency to vibrate at?
SUMMARYSUMMARY
• What must be true for resonance to occur?What must be true for resonance to occur?
• How do you know when it is occuring?How do you know when it is occuring?