Acoustical testing can be classified according to the test setup: Response testing involves a sound-level meter (SLM) and/ or a real-time analyzer (RTA) to measure the sound level and/ or spectrum produced by a source. Stimulus-response testing incorporates an acoustical source whose sound output is known, and measurements of the resulting sound field are made in order to determine how a room or other enclosure affects the sound. Sound-system performance, reverberation, and echo testing exemplify this type of test.
The second type of testing requires a source with a certain directivity (polar response) and frequency response. The directivity of an acoustical source depends upon its physical characteristics and size.
A source that is small compared to the wavelength of the sound being investigated is called a point source and is omnidirectional. Directivity can be represented in any of several ways.
One way is a simple graph of the beamwidth plotted versus frequency. The directivity graph of an omnidirectional source would be very boring: a horizontal line showing a beamwidth of 360° at all frequencies. Another way is to represent the radiated sound field as a balloon whose shape and coloration represent the sound pressure level SPL) radiated in each direction.
The third way is a section drawing with a vertical or horizontal cut through the balloon. Such sections often show multiple lines, illustrating the variation in directivity with frequency.
Figure 2: The horizontal (upper) and the vertical (lower) directivity of the human voice vary with frequency; the standard deviation is indicated by the colored shading. (Image Source: Christoph Pörschmann, Johannes M. Arend: "Analyzing the Directivity Patterns of Human Speakers," www.researchgate.net/publication/343344151)
Source Directivity
هذه القصة مأخوذة من طبعة January 2023 من audioXpress.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 9,000 مجلة وصحيفة.
بالفعل مشترك ? تسجيل الدخول
هذه القصة مأخوذة من طبعة January 2023 من audioXpress.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 9,000 مجلة وصحيفة.
بالفعل مشترك? تسجيل الدخول
Perspectives on Automotive Sound Design - In the Era of Electric Vehicles
From combustion engine vehicles to fully electric vehicles, and from sound systems in the car to sound design and synthesis for the car itself, everything is changing in the automotive industry. This conversation with two members of the DSP Concepts automotive team with vast experience in the field, John Whitecar, VP of Product Management, and Steve Ernst, Head of Business Development, offers valuable insights on how things are evolving.
Audioscenic: From Vision to Product
Audioscenic is an innovative 3D audio beamforming technology company spun off from the University of Southampton. It is a remarkable example of perseverance, from early development to the first commercial implementation, which audioXpress considered Best of Show at CES 2023. This article shares the story so far, as Audioscenic continues its groundbreaking journey exploring consumer applications for its forward-thinking approach to spatial audio.
The Changing Audio-Ecosystem in Electric Vehicles
The rapid shift to plug-in hybrid and full-battery electric vehicles is having a significant and long-lasting impact on how audio systems are integrated into cars. While some noises are much more prominent due to the absence of the familiar engine noise, the transition offers exciting possibilities for sound systems, passenger entertainment, and enhancing the overall automotive experience.
A (Z)OTL with 300Bs: Part 1-The Makeover
Rebuilding an amplifier for reasons of better reliability, better aesthetics, or bringing it up to the latest standard can be very rewarding. And if it is a classical, technological grandstand, even more so. Thomas Perazella embarked on such an adventure with a famous David Berning ZOTL amplifier. In Part 1 of this article, Tom presents the amplifier and discusses its unique circuitry. In Part 2, he will proceed to dismantle and rebuild the amp for the new owner and place it in a new chassis
The Hypex NCORE NCx500 Amplifier Module
NCORE (NC) amplifier modules are the flagship product from Dutch manufacturer Hypex Electronics and its success among the high-end audio brands is well documented. In 2022, Hypex announced the introduction of its improved NCOREX technology, starting with the NCx500 OEM module, which audioXpress received for review
Monoblock Power Amplifier with Precision Bias Control
In Part 2, Bruce Gillingham discusses the remainder of the MB1's circuitry, its mechanical design, and its performance measurements
A Trip Down Memory Lane
The history of tube application began with radio receivers, the telephone system, and cinema sound systems. Later, tubes began to be used in home stereo systems, and in amplifiers for electric guitars. Today, the primary markets for tubes are high-end stereo and musical instrument amplifiers. In this article Richard Honeycutt remembers his first contact with \"starter\" guitar amps as a teenager, progressing throughout his days as a semi-pro musician
The Vanderveen Trans PP80 Valve Amplifier
This new push-pull (PP) valve amplifier, featuring the Trans technique, delivers 80W power, refined resolution, valve-sound envelopment, and low distortion plus good speaker damping. And... the amp is simple to construct
Accuracy in LTspice Modeling
Sometimes we need to consider the human factor when using circuit design simulation tools. In this article, our hollow-state expert details an error that occurred in a past article, which is now being corrected.
Transitioning Audio Tests from R&D to the Production Line
Production line audio testing poses many challenges such as noisy environments, harsh operating conditions, high throughput, relative limits, and more. In this article, Steve Temme shares his observations and outlines the main considerations to ensure a successful operation.
