Industry & Product News
DTS and HD Radio Owner Xperi to Merge with TiVo
Xperi Corp. - the owner of DTS and HD Radio - and TiVo Corp. announced they entered into a definitive agreement to merge, in an all-stock transaction representing approximately $3 billion of combined enterprise value. The transaction creates a much larger consumer and entertainment technology business and one of the industry's largest intellectual property (IP) licensing platforms with a diverse portfolio of entertainment and semiconductor intellectual property.   Read More
Martin Audio Acquired by Focusrite
Another year, another new owner for Martin Audio. This time, Focusrite plc., which comprises the Focusrite, ADAM Audio, Novation, and Ampify Music brands, announced the acquisition of Martin Audio, Ltd. and associated companies. The acquisition of the British, Buckinghamshire-based designer and manufacturer of high-performance loudspeaker systems for the touring and installation markets, follows hot on the heels of the purchase of Berlin, Germany-based studio loudspeaker manufacturer ADAM Audio, but it has been a consideration for Focusrite Founder and Chairman Phil Dudderidge for years .    Read More  

Redefining the Shape of Sound: Resonado Introduces Flat Core Speaker Technology at CES 2020
Resonado, a South Bend, IN, company founded at the University of Notre Dame, has a new take on electrodynamic speaker topology. The company developed a reconfigured speaker with a planar voice coil mounted perpendicularly to its flat "race track" diaphragm, to which Resonado calls Flat Core Speaker (FCS) technology. The ingenious architecture enables slightly thinner, lighter, and more efficient speakers than conventional equivalents. Applications are wide-ranging from soundbars, home theater, column speakers, and automotive to headphone drivers .    Read More  
 
New ICEpower 200AS2 Compact Amplifier Module Now Available
Ideal for active speakers, studio monitors, and stereo amplifiers, the new ICEpower 200AS2 amplifier module is now in stock and ready for purchase, confirms the Danish Class-D audio amplification company. Part of the AS amplifier family, a series of highly competitive, high efficiency, ultra-compact, and lightweight modules, "ready to rock'n roll," the new ICEpower 200AS2 features a capable 300 W fly back power supply, combined with a 2 x 215 W Class D amplifier .    Read More  


GraphAudio to Provide World's First Demo of Pure Graphene Speaker at CES 2020
Following years of intense research and development work, GraphAudio will debut and demo its proprietary 100% graphene speakers at the 2020 Consumer Electronics Show (CES) in Las Vegas, NV. For demo purposes, the technology will be implemented in an earbud, amplifier, and microphone and attendees are invited to visit GraphAudio at The Venetian to experience the pure graphene-powered speaker's enhanced, high-definition, audiophile-quality sound .    Read More  


JBL Launches Indiegogo Campaign for New Self-Charging Headphones Using Exeger Light Charging Technology
Through a new strategic approach, JBL is promoting a new sustainable, solar-powered headphone model, the JBL REFLECT Eternal. A first for the brand, JBL is using Indiegogo to crowdsource interest for a solar-powered headphone with unlimited playtime. This concept marries a light converting material from Swedish brand Exeger into an on-ear JBL form-factor for everyday use. By collaborating directly with potential users, JBL hopes to gain insights on self-charging, eco-friendly technology to ensure it meets their needs .    Read More  
   
 
USound MEMS Microspeakers Now Available as Components, Development Platforms, and Reference Designs
Austrian microspeaker company USound offers the most advanced MEMS Microspeakers initiative currently in the market. Since announcing a production partnership with STMicroelectronics in 2017, the world's first miniature piezoelectric microelectromechanical systems (MEMS) actuators for smart audio systems in portable devices have become a commercial reality. Targeting multiple possible applications from headsets to high-end speakers and completely new development ideas, USound has announced multiple reference solutions to push the technology forward.    Read More


RCF Group Announces Acquisition of Montarbo
The RCF Group, one of the fastest-growing group of companies in the professional audio market, announced that it has completed the acquisition of Montarbo, an historic Italian brand with one of the most extensive product catalogs in the pro audio sector. From an operational standpoint, the brand's operations and distribution will be overseen by AEB Industriale. According to the Reggio Emilia company, the incorporation of Montarbo further expands the group's product range in a market that is demonstrating strong growth .    Read More  

Neville's Musings
 
Neville Roberts
 


The Imperfect Room
What is the perfect room for listening to music?
I was having a discussion with a friend of mine recently about what makes a good listening room. Our initial thoughts were that an ideal listening room would be one that doesn't generate any sonic artifacts, so nothing would be added to the sound generated by the loudspeakers. Surely, in such a "perfect" room, whether you are listening to Beethoven's majestic Ninth Symphony recorded in a great concert hall, or to one of his more intimate quartets recorded in a small room, your loudspeakers would be able to convey all the unpolluted musicality and ambience that has been captured by the microphones during the recording process.  Well, that all sounds very good in theory, but in practice it's not that simple. 

A room that adds nothing to any sound generated within that room is known as an anechoic chamber. Apart from the obvious qualities of having a tight-fitting door that does not rattle, it is a room that has acoustic properties comparable to being high above the ground in the open air, because there are no reflections from the walls, the floor, or the ceiling. Such rooms or chambers don't have any effect on the measurements so they are ideal for testing the responses of loudspeakers and microphones. 


An anechoic chamber is usually a solidly built room fitted with a heavy acoustic door with rubber seals to minimize the external sounds entering the environment. The inside walls, ceiling and floor are cladded with acoustic foam wedges to absorb sound and a wire frame is fitted above the foam on the floor to allow you to walk on it. The similarity in appearance between the foam wedges and egg boxes has led some people to fix egg boxes to the walls in an attempt to reduce reflections in their listening rooms. Unfortunately, due to their hollow nature, egg boxes are far from the ideal choice as a means of reducing sound reflections. Tests have shown that they also do nothing to absorb low frequencies; in fact, they have a non-flat absorption characteristic with a peak at around 800 Hz - not good!

The anechoic chamber is an extremely quiet environment, but it can feel quite eerie because no sound from the outside world enters your ears. When no music is playing, you might hear the blood gently pumping through your head, a high-pitched hiss caused by spontaneous firings of your auditory nerve or actual ringing in your ears if you suffer from tinnitus. Normally, these internal sounds are masked by external noises, but in an anechoic chamber these sounds become all too apparent and can be quite spooky. None of these effects are experienced in a concert hall or an intimate, small room when no music is being played. 

But what is the best acoustic environment for recording purposes? The record label Chasing The Dragon made two audiophile recordings of J S Bach's "Cello Suite No.1," using an identical arrangement of three microphones, but one was recorded inside a church and the other was recorded outside in a large, open space. The version recorded outside sounded acoustically dead compared with the recording inside (which was probably not surprising as the open space was actually an old graveyard!). All this clearly demonstrates that an anechoic chamber is far from an ideal environment for either listening or recording, but why should this be so?

The human auditory system is a complex arrangement of reflections and diffractions around the physical features of the head. The delays between sounds reaching one ear with respect to the other ear, together with the diffractions around the features of the outer ear, are all used by the brain to provide spatial information for instrument positioning, reverberation and room ambience. A pair of loudspeakers in an anechoic chamber cannot reproduce this additional information required by the brain to effectively construct a 3D acoustic environment. Attempts to re-create 3D sound resulted in the rise (and fall) of quadraphonics in the 1970s and the subsequent rise of surround-sound systems. The reality is that you need considerably more than a handful of point-sources (loudspeakers) to re-create the acoustic environment of either a large hall or a small room - the human brain is not that easily fooled.


Many factors need to be considered if you want to create a good listening environment. Of course, all the window and the door rattles in a listening room need to be eliminated and room Eigentones (standing waves) need to be managed. However, in order to provide your body with the plethora of sound input that will allow your brain to re-create a believable audio environment, I believe that you still need the very subtle effects that are generated by your actual listening room to be present, along with the sounds from your loudspeakers. Bass traps and sound diffusors are very effective devices for managing many of the audible peaks and troughs in a practical listening room, and appropriate positioning of both the loudspeakers and the listener can also enhance the acoustic experience. In addition to all this, however, in order to create a believable listening environment, there is still something else that you require, such as a little sound reflected from the rear wall or the ceiling.

Getting a room to sound right in a practical way cannot be achieved by simply removing all of the room's personality. At the end of the day, room-tuning has to be done by ear and this is an essential part of creating the unattainable goal of a perfect listening room. Achieving perfection requires an element of imperfection to be present - but just the perfect amount of imperfection.

Book Review
A Look Inside Bob Cordell's Designing Audio Power Amplifiers, 2nd Edition
By  Jan Didden
 
We know many of our readers will enjoy this extended book review by our technical editor, Jan Didden, about Bob Cordell's Designing Audio Power Amplifiers, 2nd Edition. When Cordell published his long-awaited first edition of Audio Power Amplifier Design, it was hailed as a significant addition on the subject. Reactions of readers made it clear that Cordell hit his mark, and in this article, Didden explains why the long-awaited second edition is an essential buy.   This article was originally published in audioXpress, October 2019 .    Read the Full Article Now Available Here

Voice Coil  Test Bench
B&C Speakers DCX464 High Power Coaxial Compression
By  Vance Dickason
 
The driver to be characterized in this Test Bench is from B&C Speakers and is the DCX464, a pretty unusual ring radiator compression driver. First, because it's a coaxial compression driver - a rare category of compression driver, and second because the DCX464 compression driver and the accompanying horn measure down to an honest 300 Hz, which is quite a low frequency considering only a few OEM horns on the market go even as low as 400 Hz. To have that low a cut-off frequency, the horn supplied with the DCX464 is huge with a mounting flange that measures 23.5" x 17.5" and a depth of 17.5". B&C Speakers supplied the Tromba horn (Tromba is Italian for trumpet or horn) as a 3D printed and a fiberglass reinforced prototype with an 80° x 60° coverage pattern in the midrange. In terms of features, the DCX464 ring radiator is listed as a 1.4" (36 mm) throat compression driver, and that is for both the midrange driver and the high-frequency driver, which means that B&C Speakers has found a way to mix both drivers in the same throat. This is done with a patent-pending midrange integrator that allows both diaphragms to work together over a wide frequency range without causing any major magnitude or phase errors. Definitely, a configuration that deserves careful characterization. This article was originally published in Voice Coil, October 2019 .    Read the Full Article Now Available Here

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