Helmholtz vowel resonator, OU
Date: circa 1865
Inventory Number: 2000-1-0010a
Classification: Helmholtz resonator
Maker: Rudolph Koenig (1832 - 1901)
User: Department of Physics, Harvard University ? (founded 1884)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
9.5 × 7.4 × 7.4 cm (3 3/4 × 2 15/16 × 2 15/16 in.)
Material:
Description:
Brass sphere with two openings, one larger than the other. The larger opening is a circle cut into the sphere with a slight ridge on the diameter. The smaller opening is at the end of a tapering protrusion from the sphere.
In Collection(s)
SignedStamped: "RK"
Inscribedon red rimmed tag that has detached from the instrument: 19-2-5
FunctionOne of a set of five resonating spheres. The smaller opening would be placed in the ear; the larger one would admit the sound waves. The sphere would resonate at a particular frequency. According to Helmholtz in On the Sensations of Tone as a Physiological Basis for the Theory of Music (Longmans, Green, 1885): 43, "The mass of air in a resonator, together with that in the aural passage, and with the tympanic membrane or drumskin itself, forms an elastic system which is capable of vibrating in a peculiar manner, and, in especial, the prime tone of the sphere, which is much deeper than any other of its proper tones, can be set into very powerful sympathetic vibration, and then the ear, which is in immediate connection with the air inside the sphere, perceives this augmented tone by direct action. If we stop one ear (which is best done by a plug of sealing wax moulded into the form of the entrance of the ear), and apply a resonator to the other, most of the tones produced in the surrounding air will be considerably damped; but if the proper tone of the resonator is sounded, it brays into the ear most powerfully."
Helmholtz argued that vowels, also, were associated with particular tones, and this depended on the arrangement of the mouth. For example, "for the vowels of the lower series, O [o in more] and U [oo in poor], the opening of the mouth is contracted by means of the lips... The pitch of such a bottle-shaped chamber is lower the larger its cavity and the narrower its mouth. Usually only one upper partial with strong resonance can be clearly recognised...We find that for a very deep hollow U [oo in poor nearly], where the oral cavity is widest and the mouth narrowest, the resonance is deepest and answers to the unaccented f" (106).
Helmholtz argued that vowels, also, were associated with particular tones, and this depended on the arrangement of the mouth. For example, "for the vowels of the lower series, O [o in more] and U [oo in poor], the opening of the mouth is contracted by means of the lips... The pitch of such a bottle-shaped chamber is lower the larger its cavity and the narrower its mouth. Usually only one upper partial with strong resonance can be clearly recognised...We find that for a very deep hollow U [oo in poor nearly], where the oral cavity is widest and the mouth narrowest, the resonance is deepest and answers to the unaccented f" (106).
Primary SourcesRudolph Koenig, Catalogue des appareils d'acoustique construits par Rudolph Koenig (Paris, 1889), p.25, No. 56.
ProvenanceRed rimmed label is of type found with acoustic instruments coming from the Physics Department, Harvard University.
