Koenig's Apparatus for the Analysis of Sound

From school sessions to family drop in activities and adult lectures, the Whipple Museum's educational programme can offer something to visitors of all ages and interests. Our learning coordinator is part-time so taught education sessions are available on Tuesday afternoons, Wednesdays and Thursdays, subject to availability. Find out more about sessions here and use our booking pageto check availability and book your visit. Outreach talks can take place at other times on request. 

You are welcome to co-ordinate your visit to the Whipple Museum with visits to other University of Cambridge Museums and Collections.

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Information for Groups and schools

The Whipple Museum is keen to engage with schools and groups and can offer on-site, digital and/or outreach versions of our learning sessions for anyone from early years to adult groups. Sessions typically last an hour to an hour and a half and include practical activities, handling objects, a tour or virtual tour of the museum and a chance to ask questions. All groups over 10 people must be pre-booked at least a week in advance. Our offer more information if you need it. 

Families and other events

Visit the What's On section for more information on our other events and exhibitions.

The Whipple Museum can offer on-site learning sessions from early years to adult groups on Tuesdays, Wednesdays and Thursdays, subject to availability. Our maximum group size is 45 for taught sessions and 30 for self-led groups. Taught sessions typically last up to an hour and a half and include practical activities, information about objects and a chance to ask questions. Home educating families are welcome to book any of the schools sessions, there are no minimum numbers. You are also welcome to visit the museum as a self-led group on other days of the week. Please use our booking system to find a time which suits you and book your session here. School and group sessions at the museum are free of charge, although donations are welcome either using the donations box at the museum or online. See adult groups section for charges for outreach talks. 

Primary Schools

• Being a scientist (KS1 or KS2)
• Light  (KS2)
• Earth and Space (KS1 or KS2)
• The Science of Musical Sound (KS2)
• The Human Body (KS1 or KS2) 
• Scientific Women (KS2 or KS3)

Secondary Schools/Post 16

• Scientific Women (KS2 or KS3) 
• Science, Exploration and Empire(KS3 or KS4)
• Medicine and Anatomy through Time (KS4 or KS5)
• Modelling Science (KS4 or KS5)

Adult groups - talks with objects from the museum

• Seeing science: objects from the Whipple Museum
• Scientific Women

Please contact Alison on are26@cam.ac.uk to arrange a talk or a visit to the museum for an adult group. Visits to the museum are free, although donations are welcome; an outreach talk costs £50 or £35 for smaller groups or those who are struggling financially. 

Adjustments and Accommodations

If something catches your eye but might need some adjustment to suit your group, please let us know and we'll do our best to adapt it to your needs.

This late 19th-century apparatus (image 1) is part of a sound analysis device. It imitates a design by Rudolph Koenig for what is considered the first spectrum analyzer. It is displayed alongside a flame manometer and a rotating mirror (image 3), which would have formed crucial parts of this analysis machine.

Description

The object in image 1 consists of ten Helmholtz resonators arranged in a wooden frame, and was acquired from the Wheatstone Laboratory, King's College London, in the 1980s. The resonators were made by Rudolph Koenig in the late 19th century, but the maker of the frame is not certain. Most probably this apparatus was assembled at King's as a more affordable version of Koenig's apparatus for the analysis of sound, using a standard set of resonators.

Background

Musical sounds and the vowels of human speech have their particular sound quality, or timbre, in virtue of the specific overtone frequencies present at various intensities. That is, a musical note at concert A 440Hz, for example, will contain that frequency as well as a series of harmonic partials at integer multiples of 440 (e.g., 880Hz, 1320Hz, etc) at varying intensities. It is the particular spectrum of overtone intensities that gives musical notes their particular timbre. Using resonators held against his ear, Herman von Helmholtz was able to detect the presence of these overtones and thus perform an analysis of the sound. This practice, however, left an unwelcome element of subjectivity in acoustic experimentation. With his analysis device, Koenig removed this flaw by designing a way to make the specific composition of sounds visible as well as audible.

Operation

In Koenig's design (image 3) each resonator has one end open to the air and the other end attached to a rubber pipe. That pipe is connected to a 'flame manometer' capsule, consisting of two hemispheres separated by a thin rubber diaphragm. One hemisphere is connected to the resonator via the pipe, and through the other hemisphere flows a flammable gas, which burns at the end of a narrow jet pipe at the top. The pressure of the gas in the capsule is dependent on the pressure of the air in the other hemisphere, which in turn is dependent on the vibrations of air within the resonator. Thus, during resonance, the gas flame vibrates in sympathy rendering visible the presence of the given frequency in the sound under investigation. An experimenter would then sing or make a sound in front of the open resonators and observe the vibrations of the flames in a rotating mirror, acting like a stroboscope, which made it easier to see the vibrations (image 4). Flame manometers were also used with the "Trombone de Koenig", as well as for many other acoustical experiments.

manometric_flames.jpg