Ronald Aarts

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Ronald M. Aarts, (born 1956), is a Dutch electrical engineer and physicist, inventor and professor in the field of electroacoustics and in biomedical signal processing technology.

Contents

Biography

Ronald M. Aarts received a BSc degree in electrical engineering in 1977 and a PhD in physics from Delft University of Technology in 1995. He joined the Optics group at Philips Research Laboratories (formerly known as the Natlab), Eindhoven, Netherlands, in 1977. His research initially involved servo systems and signal processing for use in both Video Longplay players and compact disc players. In 1984 he joined the Acoustics Group at Philips working on developing CAD tools and signal processing for loudspeaker systems [1] [2] . In 1994 he became a member of the Digital Signal Processing (DSP) group at Philips and has led projects on the improvement of sound reproduction by exploiting DSP and psychoacoustic phenomena. [3]

In 2003 he became a Philips Fellow and extended his interests in engineering to medicine and biology, in particular sensors and their signal processing for ambulatory monitoring, sleep, cardiology, perinatology, drug response monitoring (DRM) systems, and epilepsy detection. [4] He is the author or co-author of more than 450 published papers and reports and has been credited with more than 250 patent applications, including more than 175 U.S. (more than 100 of which were granted). For his creative contributions at Philips, he received the company's Gilles Holst Award (1999), the Gold Invention Award (2012) [5] and the Diamond Invention Award (2018). [6]

He became an IEEE Fellow in 2007 [7] and receiving their Chester Sall Award in 2017 [8] and in 1998 he became an Audio Engineering Society Fellow and was awarded their silver medal in 2010. [9] He was also co-organizer and chairman of several international conventions.

Aarts has been a part-time professor at Eindhoven University of Technology (TU/e) since 2006, where he mainly supervises Master and PhD students. Since 1990 he has been president of the Aarts Consultancy. In 2019, he retired from Philips and now focuses mainly on his academic and consultancy work, the latter encompassing both technical and intellectual property (IP) advice.

He married Doortje Ultee (1956-2009) in Krommenie on 14 September 1978. From their marriage two sons were born.

One of Aarts’ quotes is: "I’m an advocate for the four P’s: People (Cooperations), Patents (Engineering), Papers (Science), and Products (Valorization). Those four P’s have been keeping me ticking for over 40 years."

Professional work

Bass sound enhancement

Aarts and his collaborators at Philips have been involved in the development, improvement, and hardware implementation of bass enhancement/restoration systems exploiting the natural psycho-acoustic phenomenon known as the "missing fundamental". [10] [11] Small loudspeakers are in general not capable of reproducing low-frequency notes, but by exploiting auditory illusions one can use either the virtual pitch phenomenon to shift the low frequencies to a higher frequency band where the loudspeakers are capable, this is sometimes referred to as Ultra Bass; [12] or, one can map the very low frequency to one single frequency where the loudspeaker is designed for high efficiency, this is sometimes referred to as Bary Bass. [13] On the other hand, if the loudspeaker is capable of radiating low frequencies, but if they are not present in the music, those frequencies can be derived from the music using a bandwidth extension scheme, this is sometimes referred to as Infra Bass. [14] Finally, the audio quality, especially from high Q low-frequency sound transducers, can be improved by attenuating decay parts of bass signals thereby reducing sustain or ringing for bass notes, this is sometimes referred to as punchy bass. [15]

Loudspeaker arrays and their radiation

Aarts and his coworkers at Philips have also been involved in the design and applications of loudspeaker radiation. An extended version of the Zernike polynomials, known as ENZ, [16] was applied to solve forward and inverse problems in acoustic radiation of a flexible circular piston surrounded by a rigid infinite plane (baffle) and of a flexible spherical cap on a rigid sphere, showing that the latter is quite similar to that of a real loudspeaker. [17] The use of several loudspeakers arranged in an array allows special radiation characteristics. For example, one can increase the sweet spot area during stereophonic listening by making use of interaural time differences, this system was called position-independent stereo. [18] Another application is to direct the sound to a listener without disturbing others, this is known as personal sound. Yet another application is to use quadratic phase arrays to design loudspeaker arrays that radiate just like a single loudspeaker. [19] For loudspeaker radiation calculations the Struve function is often needed, simple approximations have been derived for this.

Stereo base widening

On small TVs and portable audio equipment, the speakers are close together. With special signal processing, so-called phantom or virtual sources can be made so that the sound seems to be generated far outside the loudspeakers. This principle has been applied by Philips to many TV and audio sets, under the commercial name 'Incredible sound'. [20] The director Spike Lee made a commercial for this in 1996, which was set on Wall Street in NYC. [21]

Acoustic cooling with loudspeakers

A small loudspeaker in a special housing can generate synthetic jets that offer advantages over a fan, such as higher efficiency, greater design freedom, and less noise and wear. [22] Experiments have shown that for small surfaces up to approximately 40 cm2, the synthetic jets cool better and make less noise than a fan.

Ambulatory or unimpeded patient monitoring

Monitoring of, e.g., epilepsy, sleep, and heart problems such as atrial fibrillation; and vital signs such as blood pressure, heart rate, and respiratory rate, can be performed without hindering the patient using a photoplethysmogram (PPG). A PPG sensor can easily be built into a bracelet such as a sports watch, preferably extended with accelerometers. [23]

Publications

A list of published articles and US-patents can be found on the homepage of Ronald M. Aarts. [24]

Related Research Articles

Beam steering is a technique for changing the direction of the main lobe of a radiation pattern.

<span class="mw-page-title-main">Subwoofer</span> Loudspeaker for low-pitched audio frequencies

A subwoofer is a loudspeaker designed to reproduce low-pitched audio frequencies, known as bass and sub-bass, that are lower in frequency than those which can be (optimally) generated by a woofer. The typical frequency range that is covered by a subwoofer is about 20–200 Hz for consumer products, below 100 Hz for professional live sound, and below 80 Hz in THX-certified systems. Thus, one or more subwoofers are important for high-quality sound reproduction as they are responsible for the lowest two to three octaves of the ten octaves that are audible. This very low-frequency (VLF) range reproduces the natural fundamental tones of the bass drum, electric bass, double bass, grand piano, contrabassoon, tuba, in addition to thunder, gunshots, explosions, etc.

<span class="mw-page-title-main">Loudspeaker</span> Converts an electrical audio signal into a corresponding sound

A loudspeaker is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A speaker system, also often simply referred to as a speaker or loudspeaker, comprises one or more such speaker drivers, an enclosure, and electrical connections possibly including a crossover network. The speaker driver can be viewed as a linear motor attached to a diaphragm which couples that motor's movement to motion of air, that is, sound. An audio signal, typically from a microphone, recording, or radio broadcast, is amplified electronically to a power level capable of driving that motor in order to reproduce the sound corresponding to the original unamplified electronic signal. This is thus the opposite function to the microphone; indeed the dynamic speaker driver, by far the most common type, is a linear motor in the same basic configuration as the dynamic microphone which uses such a motor in reverse, as a generator.

<span class="mw-page-title-main">Electrostatic loudspeaker</span> Sound playback device

An electrostatic loudspeaker (ESL) is a loudspeaker design in which sound is generated by the force exerted on a membrane suspended in an electrostatic field.

<span class="mw-page-title-main">Ambisonics</span> Full-sphere surround sound format

Ambisonics is a full-sphere surround sound format: in addition to the horizontal plane, it covers sound sources above and below the listener.

<span class="mw-page-title-main">Surround sound</span> System with loudspeakers that surround the listener

Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener. Its first application was in movie theaters. Prior to surround sound, theater sound systems commonly had three screen channels of sound that played from three loudspeakers located in front of the audience. Surround sound adds one or more channels from loudspeakers to the side or behind the listener that are able to create the sensation of sound coming from any horizontal direction around the listener.

<span class="mw-page-title-main">Amar Bose</span> American engineer (1929–2013)

Amar Gopal Bose was an American entrepreneur and academic. An electrical engineer and sound engineer, he was a professor at the Massachusetts Institute of Technology for over 45 years. He was also the founder and chairman of Bose Corporation.

<span class="mw-page-title-main">Sound reinforcement system</span> Amplified sound system for public events

A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers in enclosures all controlled by a mixing console that makes live or pre-recorded sounds louder and may also distribute those sounds to a larger or more distant audience. In many situations, a sound reinforcement system is also used to enhance or alter the sound of the sources on the stage, typically by using electronic effects, such as reverb, as opposed to simply amplifying the sources unaltered.

<span class="mw-page-title-main">Horn loudspeaker</span> Loudspeaker using an acoustic horn

A horn loudspeaker is a loudspeaker or loudspeaker element which uses an acoustic horn to increase the overall efficiency of the driving element(s). A common form (right) consists of a compression driver which produces sound waves with a small metal diaphragm vibrated by an electromagnet, attached to a horn, a flaring duct to conduct the sound waves to the open air. Another type is a woofer driver mounted in a loudspeaker enclosure which is divided by internal partitions to form a zigzag flaring duct which functions as a horn; this type is called a folded horn speaker. The horn serves to improve the coupling efficiency between the speaker driver and the air. The horn can be thought of as an "acoustic transformer" that provides impedance matching between the relatively dense diaphragm material and the less-dense air. The result is greater acoustic output power from a given driver.

<span class="mw-page-title-main">Wave field synthesis</span> Technique for creating virtual acoustic environments

Wave field synthesis (WFS) is a spatial audio rendering technique, characterized by creation of virtual acoustic environments. It produces artificial wavefronts synthesized by a large number of individually driven loudspeakers from elementary waves. Such wavefronts seem to originate from a virtual starting point, the virtual sound source. Contrary to traditional phantom sound sources, the localization of WFS established virtual sound sources does not depend on the listener's position. Like as a genuine sound source the virtual source remains at fixed starting point.

<span class="mw-page-title-main">Loudspeaker enclosure</span> Acoustical component

A loudspeaker enclosure or loudspeaker cabinet is an enclosure in which speaker drivers and associated electronic hardware, such as crossover circuits and, in some cases, power amplifiers, are mounted. Enclosures may range in design from simple, homemade DIY rectangular particleboard boxes to very complex, expensive computer-designed hi-fi cabinets that incorporate composite materials, internal baffles, horns, bass reflex ports and acoustic insulation. Loudspeaker enclosures range in size from small "bookshelf" speaker cabinets with 4-inch (10 cm) woofers and small tweeters designed for listening to music with a hi-fi system in a private home to huge, heavy subwoofer enclosures with multiple 18-inch (46 cm) or even 21-inch (53 cm) speakers in huge enclosures which are designed for use in stadium concert sound reinforcement systems for rock music concerts.

Bandwidth extension of signal is defined as the deliberate process of expanding the frequency range (bandwidth) of a signal in which it contains an appreciable and useful content, and/or the frequency range in which its effects are such. Its significant advancement in recent years has led to the technology being adopted commercially in several areas including psychacoustic bass enhancement of small loudspeakers and the high frequency enhancement of coded speech and audio.

Sound from ultrasound is the name given here to the generation of audible sound from modulated ultrasound without using an active receiver. This happens when the modulated ultrasound passes through a nonlinear medium which acts, intentionally or unintentionally, as a demodulator.

Meyer Sound Laboratories is an American company based in Berkeley, California that manufactures self-powered loudspeakers, multichannel audio show control systems, electroacoustic architecture, and audio analysis tools for the professional sound reinforcement, fixed installation, and sound recording industries.

Dr Harry Ferdinand Olson, E.E., Ph.D. was a prominent engineer and inventor with RCA Victor, the Acoustic Research Director of RCA Laboratories, Princeton, and a pioneer in the field of 20th century acoustical engineering notably in the fields of high-fidelity, digital music synthesis, microphones, loudspeakers, acoustics, radar, submarine communication, magnetic tape and noise reduction.

Digital speakers or digital sound reconstruction (DSR) systems are a form of loudspeaker technology. Not to be confused with modern digital formats and processing, they are yet to be developed as a mature technology, having been experimented with extensively by Bell Labs as far back as the 1920s, but not realized as commercial products.

Psychoacoustics is the branch of psychophysics involving the scientific study of sound perception and audiology—how the human auditory system perceives various sounds. More specifically, it is the branch of science studying the psychological responses associated with sound. Psychoacoustics is an interdisciplinary field including psychology, acoustics, electronic engineering, physics, biology, physiology, and computer science.

<span class="mw-page-title-main">David Gunness</span> American audio engineer

David W. Gunness is an American audio engineer, electrical engineer and inventor. He is known for his work on loudspeaker design, especially high-output professional horn loudspeakers for public address, studio, theater, nightclub, concert and touring uses.

A transmission line loudspeaker is a loudspeaker enclosure design which uses the topology of an acoustic transmission line within the cabinet, compared to the simpler enclosures used by sealed (closed) or ported designs. Instead of reverberating in a fairly simple damped enclosure, sound from the back of the bass speaker is directed into a long damped pathway within the speaker enclosure, which allows far greater control and use of speaker energy and the resulting sound.

<span class="mw-page-title-main">Fulcrum Acoustic</span> Manufacturer of professional loudspeakers

Fulcrum Acoustic is an American manufacturer of professional loudspeakers, including permanent-installation loudspeakers, portable loudspeakers, subwoofers, line arrays, stage monitors, and studio reference monitors. Their research and development offices and production facilities are located in Whitinsville, Massachusetts while their administrative offices are in Rochester, NY. Fulcrum Acoustic products are sold through an international distribution network and are deployed in houses of worship, sports venues, hospitality venues, concert halls, music festivals, theaters, and nightclubs.

References

  1. ↑ "An overview of papers in the field of loudspeakers and sound reproduction produced by the chair of SPS' on AM of the TU/e" (PDF).
  2. ↑ "E. Larsen and R.M. Aarts, Audio Bandwidth extension. Application of Psychoacoustics, Signal Processing and Loudspeaker Design, J. Wiley, September 2004, ISBN 0470 85864 8".
  3. ↑ Beyond physics for superior sound tudelft.nl
  4. ↑ Lemma 1 hjmwijers.nl
  5. ↑ "Benoemingen en onderscheidingen op het Nat.Lab - PDF Free Download".
  6. ↑ "Part-time professor EE has a hundred patents to his name". 8 May 2018.
  7. ↑ "IEEE Fellows Directory - Alphabetical Listing". ieee.org.
  8. ↑ https://ctsoc.ieee.org/awards/sall.html Award voor 2015
  9. ↑ "Awards". Audio Engineering Society . Retrieved 22 October 2022. [I]n recognition for outstanding contributions to research and applications of signal processing in acoustics and sound reproduction.
  10. ↑ "Pump up the bass and let others sleep". newscientist.com.
  11. ↑ Financial Times , 1997 What the ear doesn't hear.
  12. ↑ U.S. patent 6,134,330
  13. ↑ RMA Papers Hardware for ambient Sound Reproduction
  14. ↑ U.S. patent 6,961,435
  15. ↑ U.S. patent 8,934,643
  16. ↑ "NijboerZernike.nl - Extended Nijboer Zernike Analysis (ENZ)". nijboerzernike.nl. Retrieved 14 December 2023.
  17. ↑ "Comparing sound radiation from a loudspeaker with that from a flexible spherical cap on a rigid sphere" (PDF).
  18. ↑ "Position independent stereo sound reproduction" (PDF).
  19. ↑ "On analytic design of loudspeaker arrays with uniform radiation characteristics" (PDF).
  20. ↑ Stereoverbreding Dirk van Delft NRC, 2 Nov. 1995
  21. ↑ "Philips". luerzersarchive.com. April 1996.
  22. ↑ "Synthetic Jet Cooling Part I: Overview of Heat Transfer and Acoustics" (PDF). tue.nl.
  23. ↑ "Overview of Photoplethysmography (PPG) related papers produced by TU/e-SPS chair on Ambulatory Monitoring" (PDF). tue.nl. Retrieved 14 December 2023.
  24. ↑ homepage of Ronald M. Aarts tue.nl
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