Journal of the Audio Engineering Society

2001 December - Volume 49 Number 12


Multitone Testing of Sound System Components`Some Results and Conclusions, Part 2: Modeling and Application

Authors: Czerwinski, Eugene; Voishvillo, Alexander; Alexandrov, Sergei; Terekhov, Alexander

An historical retrospective analysis of the measurement of nonlinearities in audio is carried out. A quantitative analysis of the responses of various nonlinear systems (theoretical and experimental) to a multitone signal is made, and multitone testing is compared to conventional harmonic and intermodulation measurements. The multitone test provides more accurate information about the behavior of nonlinear systems when compared to standard harmonic, two-tone intermodulation, and total harmonic distortion measurements. Modeling of the nonlinear reaction of various sound system components to a multitone signal is described.

A Method for Long Extrapolation of Audio Signals

Authors: Kauppinen, Ismo; Kauppinen, Jyrki; Saarinen, Pekka

A new method for a long extrapolation of audio signals is presented. The method is fast and can extrapolate several thousand samples of noisy audio signals. All the information for the extrapolation is taken from the signal itself, so that no additional knowledge about the signal content is required. The basic theory is presented and tested by simulation. The major problem for optimal extrapolation is the determination of the impulse response of the signal. Different methods to solve the impulse response are described. The requirements for the signals that can be extrapolated are studied. The ability of the method to extrapolate audio signals with different types of amplitude envelopes is studied and simulated. The fact that signals with exponential or polynomial amplitude envelopes can be extrapolated is proven. A mathematical measurement tool for the quality of the extrapolation is presented. The effect of noise on the extrapolation is also studied. The method is tested with real music signals.

Comparison of Numerical Simulation Models and Measured Low-Frequency Behavior of Loudspeaker Enclosures

Authors: Karjalainen, Matti; Ikonen, Veijo; Antsalo, Poju; Maijala, Panu; Savioja, Lauri; Suutala, Antti; Pohjolainen, Seppo

The vibroacoustic behavior of a set of prototype loudspeakers below 1 kHz was studied in detail by comparing measurements and element model simulations. Sound fields were measured using a microphone array of electret capsules designed for the purpose and vibrations using a laser vibrometer and accelerometers. Simulations were carried out using analytical, finite- and boundary-element methods, and finite-difference methods. The enclosure conditions were varied from a fixed wall case buried in sand to a free-standing empty box and a freestanding damped box. The applicability of each modeling technique is discussed.

High-Intensity Infrasonic Acoustic Test System that Uses a Two-Volume Helmholtz Resonator

Authors: Boesch, Jr., H. Edwin; Reiff, Christian G.; Benwell, Bruce T.

The design, mathematical modeling, construction, and testing of an acoustic test system intended to support the performance of high-intensity acoustic effects experiments on large targets at low-sonic to infrasonic frequencies described. The system uses a compressed-air source based on automotive superchargers, a low-impedance airflow modulator, and a two-volume Helmholtz resonator test chamber to achieve sustained high-purity sinusoidal sound pressure levels in excess of 155 dB in a 2.5-m3 test volume at frequencies from 2 to 20 Hz.

Standards and Information Documents

AES Standards Committee News


111th Convention Report, New York



New Officers 2001/2002

2001/2002 AES International Sections Directory

Call for Nominations for Board of Governors

Call for Awards Nominations

113th Convention, Los Angeles, Call for Papers

Bylaws: Audio Engineering Society, Inc.

Index to Volume 49


News of the Sections

New Products and Developments

Upcoming Meetings

Available Literature

Membership Information

Advertiser Internet Directory

AES Conventions and Conferences


Cover and Sustaining Members List

Editorial Staff

Institutional Subscribers: If you would like to log into the E-Library using your institutional log in information, please click HERE.

Choose your country of residence from this list:

Skip to content