The Tefifon is an audio player that uses cartridges containing plastic tape with a vertical arrangement of grooves representing sound. It is a branch of analog audio technology that shares some characteristics with other, better-known devices such as the phonograph or the 8-track tape cartridge. The Tefifon combines these developments in novel ways, introducing features that were lacking in other technologies of the era.

A windchest is a wooden box that holds air to be delivered to organ pipes, which are inserted in valved holes. These two examples were used in lectures to demonstrate the different characteristics of organ pipes of varying sizes and shapes.

A tonometer consists of a series of steel cylinders that resonate at specific frequencies upon being struck with a metal hammer. They are used as standards for high frequencies, in the same manner as tuning forks. The transverse vibrational frequencies (i.e. fundamental and harmonics) of a given cylinder depend on the length, elastic modulus, and linear density of the metal.

The double siren is an instrument that produces sounds from two sources in a way that allows the phase of one sound to be changed relative to that of the other. It is capable of producing everything in the range of a half-tone to an octave. A double siren consists of two coaxial Dove sirens—disks rotating at high speed. As air flows through a series of holes in each disk, a distinct tone is produced, the frequency of which depends on the rotational speed of the disk, and the spacing of the holes in the disk.

Source: Deutsches Museum, Munich (https://digital.deutsches-museum.de/item/4423/)

The Korg MS-10 analog synthesizer is a musical instrument capable of generating and modifying electronic signals, enabling a broad range of possible sounds. Produced by the Korg corporation in 1978, the MS-10 was a reduced model compared with other products, which often had more parts and thus offered greater flexibility.

This apparatus consists of three wires, each bent to resemble transverse waves. The wires are mounted in a rectangular brass box that was placed in front of the lens of a projector. The top two wires are identical, but positioned so that their shadows appear to move in opposite directions as a crank on the side of the box is turned. As they do this, the crests and troughs of the waves alternately lineup and overlap. The corresponding “interference” of the two waves is seen in the changing shape of the third wire.