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Frequency Response of Closed Acoustical Systems by Computer

IP.com Disclosure Number: IPCOM000075402D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Portig, H: AUTHOR

Abstract

The frequency response of closed-acoustical systems is analyzed by computer, by specifying the physical dimensions and characteristics of the acoustical system to be analyzed and computing sound pressure levels therefrom.

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Frequency Response of Closed Acoustical Systems by Computer

The frequency response of closed-acoustical systems is analyzed by computer, by specifying the physical dimensions and characteristics of the acoustical system to be analyzed and computing sound pressure levels therefrom.

Closed-acoustical systems consist of "elements" and "joints". Elements are components which have two ports open to different sound pressures, such as thin round tubes of transducers. Joints are components which have one or more ports exposed to sound pressures wherein the pressure at each port is the same, but the gas volume and gas velocity at different ports are generally different. Joints and elements used to model an acoustical system are connected to one another, each port of an element being connected to a port of a joint. Once such a physical model is specified, the physical characteristics of each joint and element are specified at 11. The characteristics for an element include the diameter of tubes and diaphragms, the length of tubes, the spring constants of transducers and the mass thereof, the voltage applied to the transducers, the effective wire lengths of the coil of the transducers, and the magnetic fields associated with the transducers. The physical characteristics of joints include their volume contents. Additionally, the properties of the gas in the system (e.g., pressure, temperature, ratio of specific heats, gas constant, viscosity, and heat conductivity) and the frequency range at which the analysis is to be performed are specified as denoted by block 13.

The computing system is programmed on the assumption that all pressure a...