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The Reflections series takes a look back on historical articles from The Journal of the Acoustical Society of America that have had a significant impact on the science and practice of acoustics.

Formants in speech signals are easily identified, largely because formants are defined to be local maxima in the wideband sound spectrum. Sadly, this is not what is of most interest in analyzing speech; instead, resonances of the vocal tract are of interest, and they are much harder to measure. Klatt [(1986). in Proceedings of the Montreal Satellite Symposium on Speech Recognition, 12th International Congress on Acoustics, edited by P. Mermelstein (Canadian Acoustical Society, Montreal), pp. 5-7] showed that estimates of resonances are biased by harmonics while the human ear is not. Several analysis techniques placed the formant closer to a strong harmonic than to the center of the resonance. This "harmonic attraction" can persist with newer algorithms and in hand measurements, and systematic errors can persist even in large corpora. Research has shown that the reassigned spectrogram is less subject to these errors than linear predictive coding and similar measures, but it has not been satisfactorily automated, making its wider use unrealistic. Pending better techniques, the recommendations are (1) acknowledge limitations of current analyses regarding influence of F0 and limits on granularity, (2) report settings more fully, (3) justify settings chosen, and (4) examine the pattern of F0 vs F1 for possible harmonic bias.

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Patents are available via the internet at the USPTO website, and also using Google Patents. [ABSTRACT FROM AUTHOR]

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Printed copies of United States Patents may be ordered at $3.00 each from the Commissioner of Patents and Trademarks, Washington, DC 20231. Patents are available via the Internet at http://www.uspto.gov. [ABSTRACT FROM AUTHOR]

The article reviews various acoustical patents that were approved in 2017, including one for a hearing device and method of identifying hearing situations having different signal sources, one for a binaural hearing assistance system and one for a hearing aid.

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Printed copies of United States Patents may be ordered at $3.00 each from the Commissioner of Patents and Trademarks, Washington, DC 20231. Patents are available via the Internet at http://www.uspto.gov. [ABSTRACT FROM AUTHOR]

The article reviews several acoustical patents in the U.S. Some of the patents evaluated include a patent for a piezoelectric micro-blower, systems and methods for controlling highly nonlinear acoustic waves or pulses, films and membranes for acoustic signal converter, signal processing apparatus and signal processing method and microelectromechanical loudspeaker array with predetermined period of time of diaphragm relaxation.

The article reviews acoustical patents. It includes the Wearable Air Blast Protection Device, Electrostatic Loudspeaker Capable of Dispersing Sound Both Horizontally and Vertically, Loudspeaker, Electrodynamic Sound-Emitting Device, Speaker Unit and Active Speaker Device, and Electronic Sound Level Control in Audible Signaling Devices.

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Printed copies of United States Patents may be ordered at $3.00 each from the Commissioner of Patents and Trademarks, WA, DC 20231. Patents are available via the Internet at http://www.uspto.gov. [ABSTRACT FROM AUTHOR]

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Printed copies of United States Patents may be ordered at $3.00 each from the Commissioner of Patents and Trademarks, Washington, DC 20231. Patents are available via the Internet at http://www.uspto.gov. [ABSTRACT FROM AUTHOR]

The article reviews the patent entitled "Acoustic Panel."

The article reviews the patent entitled "Mechanical Assembly Provided With Means for Monitoring for a Structural Anomaly, a Gearbox Provided With Such a Mechanical Assembly, and a Method of Monitoring for a Structural Anomaly."

The article reviews the patent entitled "Acoustic Characteristic Correction Coefficient Calculation Apparatus, Acoustic Characteristic Correction Coefficient Calculation Method and Acoustic Characteristic Correction Apparatus."

The article reviews the patent entitled "Acoustic Apparatus."

The article reviews the patent entitled "Audio Control of Multimedia Objects."

The article provides information on a patent describing an active acoustic touch location method for electronic devices.