2002 March, Vol 50 Number 3

CONTENT

PAPERS

Effect Design, Part 3 Oscillators: Sinusoidal and Pseudonoise
Jon Dattorro   115
This is the third of a three-part series that provides a tutorial reference for those signal processing algorithms that are of particular interest to music. In this part, the issues of low-frequency sinusoidal oscillators and sonically pleasant pseudorandom noise generators are reviewed, compared, and analyzed. Both topics actually have deep issues even though the signal definitions are simple. The historical background, pertinent references, and appendices provide the reader with a comprehensive foundation in
these subjects.

Reproducing Low-Pitched Signals through Small Loudspeakers
Erik Larsen and Ronald M. Aarts   147
Because small-volume loudspeakers are unable to reproduce low-frequencies, alternative methods can be used to create the illusion of those frequencies by taking advantage of a phantom-pitch phenomenon—the perception of a fundamental when only its harmonics are present. The low frequencies below the loudspeaker cutoff point are extracted from the wide-band signal, nonlinearly processed, filtered again, and finally injected into the path of the main signals. Listeners prefer this artificial bass in comparison to flat reproduction through a small loudspeaker. A particular implementation of phantom pitch is illustrated.

Generating Source Streams for Extralinguistic Utterances
Eduardo Reck Miranda   165
Most speech-synthesis systems do not provide a mechanism for creating nonspeechlike signals, such as sounds like boom, meow, gurgles, and genetic vocal noises. To avoid the mechanical-sounding attributes of other approaches, the author adapts a cellular automata control of the spectral parameters. The array of parameters is updated according to a set of rules to create transitions between states using the values of the neighboring cells as input parameters. While this approach works well to create natural sounds, there is
insufficient knowledge about how to create an imagined sound.

ENGINEERING REPORTS

Estimating the Loudspeaker Response when the Vent Output is Delayed
Neville Thiele   173
A method is proposed for estimating the loss in amplitude response for a loudspeaker when the acoustic output from the vent is delayed with respect to the main output. Although the model is simple, it provides insight into the way low-frequency response is influenced by lumped delay to the vent output. Designers are often forced to move the vent to a more distant location, and delay is thereby added to that acoustic path.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News   176
Audio connectors

FEATURES

112th Convention Preview, Munich   178
  Calendar   180
  Exhibitors   187
  Exhibitor Previews   184
113th Convention, Los Angeles, Call for Workshops Participants   206

DEPARTMENTS

News of the Sections   201
Upcoming Meetings   203
Sound Track   205
Membership Information   207
Advertiser Internet Directory   209
In Memoriam   212
AES Special Publications   213
Sections Contacts Directory   218
AES Conventions and Conferences   224

FPO For the cover:

2002 March, Vol 50 Number 3

spine: 2002 March, Vol 50 Number 3