Inquiry-Based Labs in Musical Acoustics M. S. Pettersen Washington & Jefferson College
Jan 14, 2016
Inquiry-Based Labs in Musical
Acoustics
M. S. Pettersen
Washington & Jefferson College
“Good Vibrations:” a course in musical acoustics for non-majors
Goal: bring active learning into a class for non-science majors
• Studies show active learning methods are more effective (Laws; McDermott; Redish and Steinberg; Birk and Foster; etc.). – Students see and hear phenomena for themselves.
• The best way to learn about science is to practice it– It’s fun, too!
… which implies that the course should:
• Include the old-fashioned kind of experiments that students can see, hear, feel
• Alternate bench-top experiments with measurements of real instruments, acoustics of campus auditoriums, etc.– Using Vernier Software’s Logger Pro– Using free software from the internet
• Incorporate music listening
Old-fashioned experiments
Siren disc Monochord (sonometer)
Melde’s apparatus Chladni plates
New-fangled experiments using Logger Pro
• Overtones
• Inharmonicity in the piano
• Percussion instruments and virtual pitch
• Differences among the woodwinds
• Sound envelope
• Echoes
• Auditorium acoustics
Inharmonicity of the piano
Percussion instruments; virtual pitch
Timpani Bass drum
Differences among the woodwinds
• Clarinet: odd overtones only (one end open, one end closed)
• Saxophone: particularly strong second harmonic
• Flute: almost pure fundamental
Auditorium acoustics
Reverberation time is about 1 s
New-fangled experiments using software; Electronic music
• Fourier synthesizer Java applet
• Spectrogram software
• Software synthesizer (electronic instruments)
• .mp3 compression with MediaMonkey
• Signal processing and sound editing with Audacity
Fourier synthesizer Java applet
http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=33
Spectrogram software
A. Aaaaaaaaaaa!
B. FFFFF
Note formants, overtones
Signal processing and sound editing with Audacity
Row, row, row your boat….
Listening
• Bach Brandenburg #2: overtones on the Baroque (valveless) trumpet
• Berlioz Requiem – Dies Irae (Tuba Mirum) – speed of sound
Sources
• Evolution eKeys Keyboards:
http://www.zzounds.com
• Auditory Demonstrations CD:
http://asa.aip.org/discs.html
• Fourier synthesizer Java applet:http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=33
• Spectrogram software:http://www.visualizationsoftware.com/gram.html
• Media Monkey audio format converter and .mp3 ripper:http://www.mediamonkey.com/download.htm
• Audacity sound editing and processing software:http://audacity.sourceforge.net