Charlie Hughes (audio engineer)

Charles Emory Hughes II (born February 13, 1965) is an American inventor and audio engineer.

He is known for his work on loudspeaker design, and the measurement of professional audio sound systems.

Hughes first worked for Peavey Electronics designing loudspeakers and horns where he was granted a patent for the Quadratic-Throat Waveguide horn used in concert loudspeakers.

He worked for Altec Lansing for two years as chief engineer for the pro audio division and was granted two more patents.

In 2021, Hughes was hired by Biamp as principal engineer.

Hughes designs loudspeakers and performs contract engineering for Excelsior Audio as co-owner.

He is an expert consultant in audio measurement and analysis software and systems.

He has led committees in prominent standards organizations to develop technical standards for the measurement, modeling and production of audio equipment.

Hughes studied physics at the Georgia Institute of Technology including audio engineering under Dr. Eugene "Gene" Patronis.

He helped maintain WREK, the campus radio station, and he spoke on the air as talent.

His senior project was a 3-way loudspeaker system that Hughes describes as sounding good but looking shabby because of his poor woodworking skills.

He graduated in 1988 with a bachelor's degree in physics.

Following college, Hughes was hired by Peavey Electronics in Meridian, Mississippi, where he worked for almost 14 years.

At Peavey, Hughes served as a loudspeaker designer and the main horn designer for loudspeaker enclosures.

He developed a new horn design as a means to improve linearity in mid- and high-frequency reproduction.

The design was primarily a simple conic section except that its throat was curved in a circular radius arc to match the desired throat size for proper mating to the compression driver.

The mathematical formula describing the cross-sectional area expansion was a quadratic equation:

This quadratic equation suggested to Hughes the name of the horn design: the Quadratic-Throat Waveguide (QT waveguide).

Instead of increasing the horn mouth size with a flare to control midrange beaming, a relatively thin layer of foam covering the mouth edge was found to suit the same end.

The QT waveguide, when compared to popular constant directivity (CD) horns, produced about 3–4 dB lower levels of second harmonic distortion across all frequencies, and an average of 9 dB lower levels of the more annoying third harmonic distortion.

Being without a diffraction slot, the QT waveguide was free from problems with apparent apex, making it arrayable as needed for public address purposes.

He served as head sound engineer and sound designer at the Meridian Little Theatre from 1989.

Beginning in 1991, Hughes teamed with Peavey Product Manager Mick Donner to form Meridian SoundWorks, a local sound reinforcement company providing gear and engineering to mix concerts, corporate and political events, and theatrical productions.

Meridian SoundWorks also provided sound system design and optimization for permanent installations.

The experience allowed Hughes to assess the performance of sound gear in real-world applications.

In 1998, Hughes was appointed to the advisory committee of Gold Line's TEF division.

In New York City, Hughes presented a paper on the technology at the Audio Engineering Society convention in September 1999.

His patent for the QT waveguide was provisionally filed on March 5, 1999, and granted on May 9, 2000.

At Peavey, Hughes measured the results of his horn experiments, and he analyzed the total performance of multiple-driver loudspeakers, especially with regard to tuning the crossover to obtain optimum results.

In this measurement he used TEF, a professional acoustical measurements and instrumentation system first made by Techron, a division of Crown International, then sold to Gold Line.

TEF is a system that incorporates Richard C. Heyser's time delay spectrometry (TDS) method to analyze sound waves.

In 2000, Hughes became an instructor of TEF II systems, part of a team that included Don Eger and Russ Berger.

Hughes joined Altec Lansing in May 2002 to serve as senior engineering manager in the professional audio division.

This included both component-level and overall product engineering for the installation market as well as for touring systems.

As of 2008 he was still on the advisory committee.

Hughes also programmed in MATLAB, a computing environment that allowed him to visualize the complex output pattern of a loudspeaker system under test.

He used MATLAB to optimize crossovers to achieve smoother directivity results at the crossover transition region.

Toward this end, Hughes developed a software tool called PolarSum which eliminated much of the drudge work of taking a great many polar plot measurements.

Hughes also used Enhanced Acoustic Simulator for Engineers (EASE), a 3D simulation tool which was developed by Wolfgang Ahnert and Stefan Feistel of Germany.

Hughes involved himself early with the more practical aspects of operating sound systems.