The document describes an experiment to test resonance in a 1.575m stairwell. It predicts resonant frequencies using the stairwell length and speed of sound, finding close matches between predicted and measured frequencies for nodes 2 through 6. It also provides proof of resonance by measuring higher amplitudes at predicted frequencies within the stairwell than outside it.

1. 
Resonance Project
Jamie Mahon, Matt Carrington-Fair, Rod Zarafshar, Forrest Crane
http://cnx.org/content/m12413/latest/StandingWaveHarmonics.png

2. Our System
 Stairwell
 Top View:
Speaker
Stairs
1.575m

3. Predictions
 Wavelength = 1.575m
 Speed of Sound = 344 m/s
 Node 2 = (nv)/(2l) = (2 * 344)/(2 * 1.575) = 218.41hz
 Node 3 = (nv)/(2l) = (3 * 344)/(2 * 1.575) = 327.62hz
 Node 4 = (nv)/(2l) = (4 * 344)/(2 * 1.575) = 436.83hz
 Node 5 = (nv)/(2l) = (5 * 344)/(2 * 1.575) = 546.03hz
 Node 6 = (nv)/(2l) = (6 * 344)/(2 * 1.575) = 655.24hz

4. Results Pt. 1
 Node 2
 Predicted Frequency = 218.41hz
 Actual Frequency = 207hz
 Node 3
 Predicted Frequency = 327.62hz
 Actual Frequency = 312hz

5. Results Pt.2
 Node 4
 Predicted Frequency = 436.83hz
 Actual Frequency = 439hz
 Node 5
 Predicted Frequency = 546.03hz
 Actual Frequency = 522hz
 Node 6
 Predicted Frequency = 655.24hz
 Actual Frequency = 659hz

6. Proof Pt.1
Stairwell
Frequency = 207hz
Amplitude = 27.7dB
Non-Resonant
Frequency = 207hz
Amplitude = 23.3dB

7. Proof Pt.2
Stairwell
Frequency = 312hz
Amplitude = 32.9dB
Non-Resonant
Frequency = 312hz
Amplitude = 27.2dB

8. Points of Interest
 Actual speed of sound in stairwell:
 ~334.2 m/s