The Sound Lab

Technical Reports | Talk Shop With John | Research & Development | Q&A

The Sound Lab is Meyer Sound's technology base on the Web. Here you'll have access to articles and papers that help explain the technology, research and design issues surrounding sound reinforcement and reproduction. In the Talk Shop with John section, John Meyer offers his view of the company's products and aspects of its goals and direction. The Research & Development section delves into Meyer Sound's proprietary components, design elements and techniques. Q&A provides important data about Meyer's technology and processes.

 
  TECHNICAL REPORTS

Whether debunking or verifying new and long-held theories, the following reports promote a higher degree of understanding and awareness of the business of sound reproduction.

 
John Meyer LEOPARD Story (October 2015)
We developed the LEO family of speakers to produce the most ideal linear speakers possible: that is, to reduce distortion to the theoretical limit. LEOPARD is a small line array element in the LEO family that wasn’t targeted to a specific market. Instead, we gave it to our engineers as a challenge to see how well it could be designed.
Frequency Response Measurements and the Meyer Sound HD‐1 High Definition Audio Monitor (April 2015)
In developing the HD‐1, Meyer Sound embarked upon extensive research to formulate methods for obtaining acoustical measurements that are accurate to within 0.25 dB of free field. This paper describes the predomi‐ nant factors that must be considered in any attempt to reproduce those measurements, and presents compre‐ hensive HD‐1 polar performance data in the form of fre‐ quency response plots.
Headroom Predictions Using B-Noise in MAPP XT (April 2015)
The equal energy per octave nature of pink noise makes it an accepted reference source to predict the SPL and headroom of a loudspeaker or loudspeaker array. Pink noise is also an excellent, albeit conservative, means of estimating the SPL a system would linearly reproduce when driven with other types of inputs that have broad spectral content.
Optimizing acoustics for spoken word using active acoustics (June 2013)
Teleconferencing, classrooms, lectures, drama, and worship all rely on spoken word to convey a message. The successful receipt of the message is largely dependent on the acoustic of the room, the vessel for the message, both in amplified and unamplified situations. A room that supports teleconferencing well will have minimal early reflections and reverberation, yet the same room may be used in a classroom environment that would benefit from early reflections. Active acoustic systems can be used to provide this acoustic energy. Early Reflection Benefit (ERB) will be revisited, and an active acoustic system utilized for speech will be described.
Electronically variable room acoustics - motivations and challenges (June 2013)
Electronically variable room acoustics, or 'active acoustics', has become an effective solution to a variety of room acoustics challenges. The motivations for considering such systems often go beyond acoustics. Energy conservation, financial considerations, historic preservation, and balancing the needs of a venue's constituencies all can play a role in the determination to employ active acoustics. This paper will discuss some practical examples, including planned renovations to the Santa Monica Civic Auditorium, home of the Academy Awards during the 1960s, a resident orchestra, legendary rock concerts, and a unique hydraulic floor to convert the Civic from a performance space to an exhibit space. The active acoustic system objectives, design strategies, and challenges will be discussed.
Active acoustics and sound reinforcement at TUI Operettenhaus, Hamburg: A case study (June 2013)
TUI Operettenhaus is a proscenium theater with one balcony which is host to drama, musical theater, and concerts. The venue hosts different sound reinforcement systems for different shows, and now has a permanent active acoustic system. The physical acoustics are very dry as is appropriate for modern theater with spatial sound reinforcement, and the active acoustic system allows the reverberation time to be extended as appropriate for different performances. The active acoustic system can also pass through signals to it's speakers for spatial surround reproduction. The installation of the active acoustic system in an older building posed many challenges. This case study presents the challenges that were overcome during installation, the integration of the active acoustic system with sound reproduction, and the measured performance of the system.
Linear Cinema Sound: A foundation for Emerging Sound formats (PDF) (September 2012)
Recently, the cinema industry has witnessed the highly publicised debuts of multi-channel surround sound formats that are promising fully immersive experiences beyond 7.1. On one level, this is a potentially significant development for movie fans. A greater sense of emotional involvement via sound could stimulate audience interest and, by extension, make cinema exhibition more competitive with other forms of entertainment. However, adopting new formats without paying attention to loudspeaker quality and linearity could risk audience disappointment and shatter a unique opportunity to extend the boundaries of cinema sound.
Calibrating Cinema Sound Systems (PDF) (June 2012)
Cinema sound systems have always had a target "calibrated" level, such that when a "reference" noise signal is fed into the system, the overall gain should be adjusted so that the measured SPL is calibrated to a reference SPL level. With the advent of digital audio now becoming the predominant means for cinema audio tracks to be delivered, there is a need to revisit and reconsider all of the implications and expectations that come along with it.
The Case for Widely Variable Acoustics (PDF) (August 2010)
Active acoustics can be employed to provide a wide range of reverberation time change for multi-purpose facilities. This paper presents a survey of preferred acoustical ranges presented for speech, reproduced sound, reinforced music, and acoustic music genres. Examples of venues that utilize active acoustics to widen their performance palette will include a worship space, performing art center, and experimental music studio. Their acoustic performance will be compared with archetypal acoustic music venues. The potential for new types of performances that are enabled by active acoustics will be discussed.
Active Acoustic Systems for the Control of Room Acoustics (PDF) (August 2010)
While active systems have historically been developed with the goal of enhancing either the stage or audience sound, they must generally provide the same control of sound as passive acoustic design. This paper discusses the principles of active acoustic systems and how they are used to achieve the required range of control. A survey of current commercial systems is given and some implications for the future of live performance are explored.
Electroacoustic Architecture: Is it Green? (PDF) (April 2010)
Electroacoustic Architecture systems offer a means of changing the acoustic properties of a room electronically. They are an alternative to physically variable acoustics, where acoustic properties are changed by retractable curtains and doors opening to reverberant chambers, etc. This paper will address the question of whether Electro Acoustic systems are a Green alternative to Physically Variable acoustics.
No-excuses Audio/Video Networking: the Technology Behind AVnu (PDF) (August 2009)
Recent work by IEEE 802 working groups will allow vendors to build a standards-based “time sensitive” network with the appropriate quality of service for professional A/V use, in a cost effective fashion. This new set of standards, currently being developed by the IEEE 802.1 Audio Video Bridging (AVB) Task Group, provides major enhancements for 802-based networks. This paper outlines the advantages of new-generation 802.1 AVB protocols and gives an introduction to those new protocols and capabilities.
AVB for Professional A/V Use (PDF) (July 2009)
Over the last decade, the high end of the Professional Audio/Video market has embraced Ethernet more and more as the predominant means for distribution in large-scale systems such as sporting facilities, convention centers, and concert halls. Due to the proprietary solutions employed, broader market applications have not been served. The recent work of the IEEE 802.1 Audio/Video Bridging Task Group offers a compelling draft standards-based solution that will broaden the professional use of networked A/V into smaller installations, studios, and additional live sound applications. This whitepaper outlines the technology and benefits for the Professional A/V market.
Making Sense of Amplifier Power Ratings (April 2005)
This paper will try to bring some clear and solid information into the discussion in the hopes that users may gain a better understanding of power amplifiers, making them better able to evaluate products. Perhaps the most common term in need of examination is “peak watts,” a popular way of expressing amplifier power.
Can Line Arrays Form Cylindrical Waves? A Line Array Theory Q&A (February 2005)
The common misconception regarding line arrays is that they enable sound waves to combine, forming a single "cylindrical wave" with special propagation characteristics. Under linear acoustic theory, however, this is impossible. The claim is not science but a marketing ploy.
The Design and Performance of the REM Ribbon Emulation Manifold Waveguide (February 2004)
On December 30, 2003, Meyer Sound was awarded a patent for the REM ribbon emulation manifold waveguide, an innovative design at the heart of Meyer Sound's line array and curvilinear array loudspeakers. The REM waveguide’s main advantages over other designs - lower distortion and tighter pattern control - are achieved due to its short length and exponentially increasing waveguide channels.
Cavities between MILO 120 Loudspeakers and the Effect of the MILO 120-I Insert on Acoustical Response (2004)
This research is a continuation of our exploration into the effects of the trapezoidal “cavity” (“Do Cavities Between Arrayed Loudspeakers Affect Frequency Response?”) created when trapezoidal (and rectangular) loudspeakers are splayed at large angles. We revisit those original experiments using improved computational tools and take a look at the cavity between MILO 120 high-power expanded coverage curvilinear array loudspeakers and the results of using the MILO 120-I insert to fill the void.
User-Defined Equalization Curves with the LD-3 Compensating Line Driver (2003)
Utilizing multiple-variable atmospheric loss equations and pre-calculated Meyer Sound MAPP Online stored values, the LD-3 compensating line driver deploys digitally-controlled analog filters that combine the wide dynamic range of advanced analog filters with the precise repeatability and computer connectivity of digital control, while exhibiting no latency.
MAPP Online Low Frequency Polar Data Acquisition (August 2003)
Below 100 Hz, the data collected in Meyer Sound's anechoic chamber has not been sufficiently accurate to give good results in MAPP Online. This paper explains how the use of a technique called Boundary Elements now allows Meyer sound to simulate the polar response of our loudspeakers below 100 Hz.
Speech Intelligibility Papers (July 2003)
Speech communication systems are subject to more stringent requirements than music systems. These pages discuss speech intelligibility in sound reinforcement - what it is, what affects it and how it is measured.
Comparison of the Directional Point Source Model and BEM Model for Arrayed Loudspeakers (PDF) (2003)
There are many approximations to the Acoustic wave equation which can be evaluated numerically which are more and less accurate at modeling different acoustical phenomena and which are more or less computationally expensive. This paper compares the Directional Point Source model and the Boundary Element Method (BEM) for modeling arrayed loudspeakers.
DSP Beam Steering with Modern Line Arrays (December 2002)
This technical report demonstrates the differences between physically steering loudspeakers and beam steering loudspeakers and identifies the main problems: the 11-octave wide range of human hearing, the near impossibility of steering the sound produced from specialty waveguides, and the unintuitive back lobes and the cone of sound.
Verification of MAPP Online's Accuracy (2002)
To verify the accuracy of Meyer Sound's MAPP Online, Meyer Sound research and development personnel used the program to model the frequency response of an M2D Compact Curvilinear Array loudspeaker system as measured from a specified physical position in a known concert hall. The staggering results are presented in this paper.
MAPP Online Pro Acoustical Information (2001)
Information on Surfaces, Sound Field Scaling,Frequency Response Scaling, Loudspeaker Data, SPL Calibration, Low Frequency Polar Data Acquisition and an Acoustical FAQ
What Is a Curvilinear Array
Pioneered by Meyer Sound in the early 1980s, curved horizontal arrays formed with trapezoidal enclosures have been an industry standard for decades. Recently, the sound reinforcement profession has exhibited considerable interest in new implementations of the line array concept. This technical report elaborates on the positive aspects of this trend.
Do Array Cavities Affect Frequency Response?
Research at Meyer Sound provides information on how loudspeaker arrays interact and also serves as a "proof of performance" for MAPP Online, the company's multipurpose acoustical prediction program.

 
  TALK SHOP WITH JOHN

From high-drivers to powered subwoofers, John Meyer takes you inside the thinking process that drove these projects.

 
About the MILO HP-4/MILO power amplifier
The development of the MILO high-power curvilinear loudspeaker provided an amplification challenge. Read about how Meyer Sound’s engineers rose to the occasion…
How to Better the Best - The Development of Meyer Sound's High Drivers
The company has invested heavily in the development of an in-house manufacturing facility for high-frequency devices. Here are the reasons why...
More of the Same, Much More - Development of the Powered UPA Series
This article reveals the thought processes behind the creation of the Self-Powered UltraSeries loudspeakers.
Development of the CQ's
The interesting story of the conceptualization of the CQ loudspeaker systems.
Powered Subwoofers
Insights into the unique properties of Meyer Sound's powered subwoofers.

 
  RESEARCH, DEVELOPMENT AND PIONEERING ADVANCES

Meyer Sound's core philosophy is that the goal of any sound reinforcement system is to please, motivate or direct an audience of any size, in any environment. To achieve this end, Meyer Sound has created products or utilized concepts that, in their design or application, are regarded as outside the norm.

 

Meyer Sound's Anechoic Chamber
In November 1994, Meyer Sound began the design and construction of an anechoic chamber — an essential tool that enables the design of loudspeaker systems that perform precisely as specified in critical sound reinforcement applications.

Patents Gallery
Meyer Sound's list of industry firsts includes trapezoidal cabinets, dedicated loudspeaker processors, self-powered loudspeakers, source-independent system measurement, parabolic long-throw transducers, cardiod low-frequency control and high-resolution measurement.
Technological Developments
The company's commitment to research and development has produced a number of true advances in the approach to sound reinforcement and reproduction.
Demystifying the Amplifier
When Meyer Sound set out to design amplifiers for self-powered loudspeakers, its engineering staff recognized that high-quality sound was only the starting point of the overall system requirements.
 
  Q&A

Our technical support, engineering, sales and service departments are often asked to provide more in-depth data about our technology and processes. Here is a selection of interesting questions. Responses are edited by John Meyer.

 

How does Meyer Sound ensure linearity in drivers and systems?

Does Meyer use true RMS limiting?

What's the offset between RMS and Peak?

How does the M3D-Sub steer without digital delay?

Please further explain the REM ribbon emulation manifold?

Can you provide m

ore technical specifications and a more elaborate description on the crossover in MILO and M2D?