Tuesday, June 19, 2012
Accord Productions Relies On Lectrosonics
The production crew of Miami, FL-based Accord Productions captures audio with a high level of speech intelligibility and natural sound quality by depending on Digital Hybrid Wireless technology from Rio Rancho, NM-based Lectrosonics.
With offices in Miami and Ft. Lauderdale, FL, Accord Productions provides production, post production, and digitizing services to the film and video industry. Its co-founder and vice president, Rocky Wyler, typically serves as the director of photography on location and also performs double duty as the company’s technology chief.
In this capacity, he is always on the lookout for new and better ways to keep the company at the cutting edge of developments as they relate to field production. A long time Lectrosonics enthusiast, Wyler reflected on a recently completed project and the impact his firm’s Lectrosonics equipment made.
“I’ve been a fan of Lectrosonics gear since the early 90’s when I first purchased some CR185 receivers and high band transmitters,” states Wyler, “so I have a pretty long history with the company. For much of our work in recent years, we’ve used UM400a beltpack transmitters with SR dual-channel slot mount ENG receivers.
“Just recently, we began working with Lectrosonics’ SMQV super-miniature, dual battery beltpack transmitters. These came in particularly handy on a new reality TV show called Ocean Models. Rounding out the gear for this project, we also had several of the company’s T4 IFB transmitters and R1a beltpack IFB receivers.
“At any given time, we had 4-5 producers on the set and each one was hooked up with the IFB gear.”
Ocean Models follows 15 international models that come to Miami to work with a new, high profile modeling agency. They were housed in a 10,000 square foot mansion on South Beach and provided with all the amenities most models never get to experience.
“There were several days where we had a good 16 – 18 mics going among the three audio guys—each of whom was equipped with digital 8-track recorders,” said Wyler. “Sometimes, the guys would have to follow the girls in opposite directions and when they split up, range became a huge factor.
“I was really pleased with the fact that our Lectrosonics gear handled this challenge beautifully. This would not have been the case with several competing wireless systems I’ve encountered.”
Wyler also reports that Lectrosonics audio quality, build quality, and reliability are equally important factors.
“Audio quality is exceptional. I love the fact that there are none of the annoying artifacts one frequently experiences with wireless systems using compandors. I’ve also been very impressed with the build quality—particularly of the new SMQV’s.”
“We used two SMQV transmitters on some of the models,” Wyler recalls. “These units are great. They’re really small and this made them easy to conceal when the girls were wearing skimpy outfits.
“I also discovered another important benefit of these transmitters. After a short while, the girls got very accustomed to wearing the transmitters and they started turning them off to make comments among themselves, which sometimes really fouled us up.
“With the SMQV’s, we locked them out so as not to interfere with our side of the production.”
Wyler was so impressed with the SMQV’s robust performance and compact form factor that he has since ordered several more units.
“As a result of our experience using the SMQV’s on this project, we are currently in the process of acquiring several more for all our reality show work. We will, of course, continue to use our UM400a’s in our industrial work. Based upon the success of our Lectrosonics equipment with this project, we will never have any other brand of wireless transmitter on our reality projects that aren’t Lectrosonics SMQV’s.”
Prior to turning his attention back to the business of the day, Wyler offered these final thoughts. “Our Lectrosonics equipment has served us extremely well over the years. The audio quality and range are excellent and the reliability is second to none.
“We have four in-house audio guys and I assure you they’re not very easy on the gear. Our Lectrosonics equipment is the only gear that seems to survive long term. I can’t imagine working in this business without it.”
Posted by Keith Clark on 06/19 at 09:18 AM
Bag End Subwoofers Deliver For BYU-Idaho Center
When the Brigham Young University - Idaho Center was opened it was home to one of the largest production theatres in North America built for the primary purpose of supporting weekly student devotional services.
The venue features 15,000 seats and a stage measuring 108-feet wide and 60-feet deep and a new sound system that delivers a warm, intimate sound experience to every member of the audience.
Essential to the success of the space was the performance of the new center’s 5-manual Rodgers digital organ which was installed by Heritage Church Organ Company. Diversified Systems was tapped to provide the new sound system which would be key to the organ’s success.
Diversified Systems worked closely with audio-video consultant Ken Fause from Auerback Pollock Friedlander and resident BYU-Idaho engineer David Mann on the project.
The new sound system includes 8 Bag End Infra-MXB dual integrators, 16 Bag End S21E-CUS self-powered subwoofers with loop-through XLR Inputs and Power-con loop-through on the cabinet for the dynamic low-end the organ required. Completing the system are 2 DiGiCo SD7 mixing consoles, NEXO GEO D10 line arrays, fill speakers and amplifiers, and Yamaha DME-64 processors.
“We had a specific vision in mind when we chose these Bag End subs,” explains Fause. “We were looking for a wave front of sub-frequency energy that would go down to 8Hz.”
To place the subs in an optimal location to produce that “front wave” of organ sound, yet not be visible to the audience, they were installed in a cavity created along an existing concrete bulkhead beneath the stage.
“One of the challenges of the project was ensuring that the processing equipment ahead of the self-powered subs would be capable of passing 8Hz,” notes Prager. “In addition we needed to make sure that the considerable sub-frequency energy under the stage would not cause the platform itself to vibrate.”
“This entire project entailed an enormous amount of planning and precision execution, ” says Fause, ” and I can’t speak highly enough of the degree of collaboration and teamwork among all involved that resulted in such great success.”
The success of the project was confirmed shortly after completion when a retired organist from the University stopped by unannounced, played the instrument, and commented that it was the closest to a pipe organ that he had ever heard. This was strong praise from him, considering that the University is also home to a world-class Ruffati pipe organ.
“In addition to organ concerts and devotional services,” David Mann points out, “The theatre has also hosted events like “Pioneers and Patriots”, which included an F-16 flyover. At these special times, we can access the subs for that extra depth of sound that brings the event to life.”
The state-of-the-art venue at this Church of Jesus Christ of Latter-day Saints university provides seating for the entire student body and community guests at regular weekly devotionals, as well as special interest events of a secular nature including guest speakers, commencement services and the performing arts. All of these may also be recorded or broadcast live over the BYUtv network, which has an international reach through many leading cable and satellite service providers.
Perfectly Angled Desktop Monitor From Dynaudio Professional Available Now
Dynaudio Professional introduces the DBM50 – the perfect active desktop monitor featuring a 7.1” woofer and a 1.1” soft dome tweeter.
Designed for desktop use, the monitors offer a perfectly angled front, a waveguide around the tweeter and an optional level controller that does not compromise the level interrelationship between speakers.
Each and every DBM50 is handcrafted in Denmark with attention to even the tiniest detail. More than 20 years of expertise in speaker design, development and manufacturing guarantees a set of monitors that go the extra mile to recreate even the smallest and most subtle details of any recording or production.
The DBM50 comes with the option of adding a sleek controller that puts the user squarely at the helm of volume control in any situation. Levels can be set and manipulated with precision and ease, completely independent of the computer or workstation in use. The DBM50 controller provides perfect tracking, which guarantees spot-on stereo imaging with unprecedented precision.
DBM50 Main Features
• Perfectly Angled for Desktop Mixing
• Every Driver Hand-built in Denmark
• Optional Master Volume Control
• 7.1” Woofer / 1.1” Soft Dome Tweeter
• 50+50 Watts
• 117 dB SPL
• Frequency Range: 46Hz - 21kHz
• Dimensions: 230 x 348 x 335 mm / 9.1” x 13.7” x 13.2”
• Weight: 7.2 kg / 15,9 lbs
Available now in the EU and in July 2012 in the US. Prices are: USD 499 MAP each; EUR 499 SSP each; and GBP 415 SSP each. The optional volume controller is priced: USD $69 MAP; EUR 69 SSP and GBP 59 SSP.
Posted by Keith Clark on 06/19 at 06:24 AM
Monday, June 18, 2012
A Practical Guide To Good Bass: Part 1, Acoustical Concepts Of Subwoofers
In sound systems, it would be terrific if loudspeakers worked like spotlights: find the loudspeaker boxes with the right directional patterns, aim them where you want sound to go, and you’re done. Of course, that’s not the way it works, especially for bass.
Ordinary bass loudspeakers are very nearly omnidirectional over their working ranges, but when you stack up a few of them, the pattern becomes more directional and more complex. Imagine if lights worked that way—a bare light bulb would illuminate the whole room, but four of them in a row would only light up some parts of it.
To make things worse, when you use multiple woofer stacks—stage left and stage right, for example—it produces wave interference (also called “comb filtering”), causing peaks and nulls in different places in the room at different frequencies. If light worked that way, then when you lit up a room with two white lights spaced some distance apart, the room would be illuminated with a rainbow of different colors.
Even beyond that, there’s the problem of reverberation, which adds its own kinds of confusion and coloration in the time dimension. That effect that doesn’t even have a parallel in lighting.
In the face of all these phenomena, how do audio professionals design subwoofer arrays and drive schemes that provide required qualities of coverage and fidelity?
If we succeed, then:
• The bass will be clear and will have constant tonal balance over the entire listening area.
• The bass sound level will be in correct balance with the midrange and high-frequency over the entire listening area.
• Negative effects of reverberation and reflection will be minimized.
• Efficiency of the equipment (sound power output per unit cost) will be maximized.
This article offers concepts and techniques for getting good bass. Our focus will be the frequency range from approximately 20 Hz to 150 Hz.
Just about everything having to do with loudspeaker array acoustics is relative to wavelength. A box or array is “large” if its dimensions—or some of its dimensions—are more than about 1.5 wavelengths across. A dimension is “small” if its dimensions are less than about a third of a wavelength.
Here are some typical wavelengths:
For normal air temperature, pressure, and humidity, the formulas for wavelength are:
Basic Directivity Rule
For ordinary sound sources, directivity is inversely related to dimension. If an object is small, its directivity is wide; if large, its directivity is narrow. (See Figure 1) Remember that “small” and “large” are measured in wavelengths, not feet or meters.
The basic directivity rule applies independently in the horizontal and vertical planes. For example, a horizontal line of subwoofers might be large horizontally and small vertically. Therefore, its directivity would be narrow horizontally and wide vertically, as shown in Figure 2.
Multiple Sources and Lobing
Many, if not most, subwoofer installations use two separate arrays on opposite sides of the stage. Sometimes these arrays are stacked on the floor, sometimes they’re flown.
Either way, the multiple sources exhibit what physicists call “wave interference”, and what audio people call “comb filtering” or “lobing”.
Figure 3 shows the directivity of a single EV Xsub woofer at 50 Hz. In this example, size of the stage is 40x20 feet. The red trace is the polar pattern. Circles are 6 dB apart. The Xsub is essentially omnidirectional.
Figure 4 shows what happens when another Xsub is added at the opposite side of the stage. The result is very different—and not better!
Because the woofers are omnidirectional, everyone in the room hears both woofers. However, the distance from each woofer to the listener is different, except in the middle. Where the distance difference equals an odd multiple of a half-wavelength, the sounds from the two woofers cancel, and the listener hears no bass, at least not directly from the woofers.
These lobes will produce uneven bass tonal balance and level in the venue. In indoor venues, the tonal balance problems are partly masked by reverberation, but the lack of clarity remains. Outdoors, there is no reverberation, and the problem is usually quite obvious.
Figure 5 shows performance of two practical cases - groundstacked rows of subwoofers, and flown subwoofer line arrays.
The only region that is lobe-free at all frequencies lies along a line running directly out from center stage. Along this line, the bass is strongest and clearest. This is the familiar “power alley” effect that makes the bass sound very good at the mix position, but does not give the mix engineer a good idea of what the rest of the audience is hearing.
The best solution for lobing problems is to use a single center cluster instead of separate left-right stacks. This works for both horizontal and vertical arrays. However, it is not often a practical solution for staging and rigging reasons.
When left-right stacks are used, lobing problems can be reduced using stacking, beamforming and/or gradient woofers. In all cases, the idea is to minimize interference between the coverage areas of the two stacks.
Beamforming is a technique by which the sound wave emitted by a large array can be aimed and shaped. In a beamformed array, the loudspeakers are driven separately (or in small groups), and each drive signal has its own delay and level.
Figure 6 and Figure 7 illustrate a typical effect of beamforming on a typical medium-sized subwoofer array. The illustrated array is four EV Xsub subwoofers. Figure 6 shows the array with no beamforming. In Figure 7, the delay values are chosen to direct the bass radiation offstage. This is a typical technique for increasing side coverage.
Beamforming only works on arrays that are large (as defined above). Controlling directivity of small arrays requires gradient techniques, which will be addressed in my next installment of this article.
The term “shading” means modifying array drive parameters for the elements on or near the ends of the array. “Gain shading” means adjusting—specifically, reducing—the drive gain for one or more elements at either end of an array.
For long arrays, shading takes the form of a gradual tapering of gain from 0 dB to about -6 dB over the last two or three elements at each end. The effect of the shading is to make the coverage pattern more regular and less frequency-dependent.
Next time, I’ll be discussing various woofer array types and applications.
NOTE: The polar patterns illustrated in this document have all been produced by the Electro-Voice LAPS 2.2A line array design program. Starting with release 2.2A, LAPS includes a subbass pattern modeling page.
Jeff Berryman served as the director of Jasonaudio, a touring sound company based in Canada, and is a senior scientist with Electro-Voice.
Related Articles by Jeff Berryman:
What Really Defines Good Bass In Sound Reinforcement?
Discussion & Analysis Of A Variety Of Bass Coverage Patterns
AKG Discreet Acoustics Modular PLUS Series Delivers For Conferencing And Presentations
With a continued focus of providing the highest quality and most versatile microphones available, AKG announces its latest addition to its installed systems – the Discreet Acoustics Modular PLUS Series.
With a wide range of goosenecks and installation modules available, the Discreet Modular PLUS Series offers optimal adaptation for all types of room setups and speakers, with quick microphone capsule exchange.
The reliability stemming from the models’ LED Ring underscores the ability to reduce the risk of operating errors, sturdy material to reduce fatigue and improved protection from signal block outs. The LED Ring uses special circuitry to operate off standard phantom power, as two separate leads carry supply voltage and provide extra shielding to the audio signal.
The Modular PLUS Series’ interface module connects the high-quality gooseneck to the phantom power source, which adds flexibility to all mounting modules. The self-cleaning connector is reliable, inconspicuous and safe – allowing for simplified and cost-effective microphone replacement.
The goosenecks themselves are tested under extreme circumstances, bent and twisted into extreme shapes, ensuring their quality and flexibility.
“AKG has specialized in developing, designing and manufacturing quality microphone capsules for more than 60 years and the Discreet Acoustics Modular PLUS Series is a testament to the continued strategy to offer the best in sound in any mic’d application,” stated Thomas Giczy, Business Development Manager Installed Sound and Conferencing, AKG. “The variety offered through the Modular PLUS Series, from the power offerings to the mounting and capsule modules, is the best in class and will provide optimum audio for videoconferencing or presentations around the world.”
The CK43 supercardioid condenser capsule offers users a 95-degree pickup angle, ideal for situations where unwanted noise pickup is a concern.
The CK49 is a reference condenser capsule with an 80-degree pickup, with clean, off-axis response. It is ideal for use with inexperienced speakers, focusing on the voice when the speaker is distant, and reducing pop if close to the mic.
AKG’s Gooseneck GN155M is a 155cm module with a heavy, shock-mount floor stand that works perfectly as a stand-alone unit or on stages placed in front of a large group of instruments or speakers. HM1000M is a reference-hanging module used to fly mics from the ceiling to record or reinforce music or speech in houses of worship, theatres or conference halls.
AKG’s PAE M reference powering module offers the phantom power for fixed and mobile installation, providing a gold-plated, 3-pin XLR connector. Its wide voltage range fits most mic mixers. PAESP M is a programmable power module for fixed and mobile installation, fitted with a unique binary coded decimal switch to recall operating modes.
PAESP M’s noiseless mic switch reduces its level by 26dB, avoiding the irritating crackling sound when phantom power is interrupted. The PAE5 M provides a 5-pin XLR connection allowing audio signal and central voltage to be fed separately.
The four different powering modules, five mounting modules and three capsule modules combine and add up to a total of 60 different microphones combinations.
Posted by Keith Clark on 06/18 at 04:15 PM
Symetrix Edge DSP Installed At One Firefly’s New Headquarters
When it came time to move into a new office space, One Firefly, LLC seized the opportunity to turn its workspace into a cutting-edge demonstration of the integrated systems it helps homeowners, commercial clients and electronic system contractors design and install.
The Hollywood, Florida-based firm is multifaceted and provides a variety of services offered under its three Firefly brands. Firefly Design Group provides system design, documentation and consulting services specializing within the integrated building technology space.
Firefly Creative is a full-service marketing and public relations agency that caters to the custom electronics industry’s member contractors and manufacturers.
Firefly Programming is a full service control system programming company.
For the flagship demonstration, Firefly Design Group senior systems engineer Mike Harrell chose Symetrix’ new SymNet Edge DSP hardware, which features a powerful open-architecture topology, modular I/O counts and types, and next-generation Dante audio bus networking, to deliver sophisticated audio processing and routing with full Crestron control system integration.
At One Firefly’s new headquarters, each of six office zones demonstrates different aspects and possibilities that will expand the horizons of its clients.
“We regularly have visitors from integration firms, end-clients and members of the design trade through our space,” states Ron Callis, One Firefly CEO. “We find it extremely helpful to show off the technologies offered by Symetrix and other leading manufacturers.”
Firefly Design Group’s Mike Harrell further explains, “Many of the A/V technology solutions that are aimed at the residential market are quite limited and lack the flexibility needed to create well-tuned and high performing systems. We’re excited to demonstrate SymNet Edge because it has all the right specifications – including powerful DSP, lossless Dante bus networking, customizable I/O, and seamless integration with either Symetrix or third party user interfaces – at a price that allows an integrator to make a profit.
“We’re really showing off the tremendous capabilities of the SymNet Edge system at our new offices so that people can see it in action.”
Three 1-rack space SymNet Edge Frames, networked into a single functional unit via Ethernet cables conveying near-instantaneous Dante bus audio, supply the audio processing for the entire facility. Each SymNet Edge Frame accommodates up to four I/O card slots, which may be fitted with four-channel analog inputs, analog outputs, digital inputs, or digital outputs.
Currently, One Firefly’s system is configured with twenty analog inputs and twenty analog outputs. The system’s varied inputs include computer outputs from around the facility, microphones, iPod docks, Blu-Ray players, and Apple TV. Crestron MC3 and DM MD8x8 processors integrate all user control into one cohesive structure. Crown CT-series amplifiers power all the passive loudspeakers in the facility.
Of the various demonstration spaces, One Firefly’s new conference room is the most elaborate. A surround sound system composed of active Genelec AIW25 left-center-right and AIC25 rear loudspeakers, and two 5041A subwoofers can convert the space into a stunning multimedia center and demonstration home theater.
The SymNet Edge provides unique processing for the surround system that is unavailable in consumer-grade surround processors. It provides a program-sensitive cutoff for the subwoofer content that effectively delivers left- and right-channel bass, in contrast to the usual fixed-cutoff, center-mono channel. More card options for Edge are currently in work.
Acoustician Michael Chafee consulted on the acoustical treatment of the new space, which included considerable work in the conference room. In addition, the SymNet Edge system provides comprehensive room tuning.
“Because we were dealing with existing construction, we weren’t able to arrange the physical space exactly as we would have liked,” said Harrell. “Nevertheless, good acoustical treatment and a full complement of room-tuning tools in the SymNet Edge system compensates quite effectively.
“It actually ends up being a better demonstration this way, because no project – no matter how high-end – is free from constraints. Here, we present strategies for working within a less than perfect environment.”
The goings on in the conference room, or any room for that matter, can be watched and listened in on from any other room. User control of this and every other system function is accomplished by Crestron TPMC-3X handheld WiFi touch-panels, TPMC-4SMD fixed-position touch-panels, and Xpanel computer-based interfaces.
In addition, Symetrix ARC-WEB, which provides password-protected system control that is fully customizable by the integrator, will be available for use on employees’ smartphones.
For Harrell, part of the attraction of SymNet Edge is its embrace of the Dante audio bus.
“I’ve been following the development of Dante for some time now, and it offers a number of important advantages for our clients,” he said. “For one, it is easily expandable up to 128 channels of lossless audio. That’s critical in the residential market, where we typically use more channels than the commercial market because every source is stereo or surround.
“The fact that Dante is nearly instantaneous is exciting.” Harrell programmed the system using SymNet Composer software, which he reported was even easier and more intuitive than the already easy and intuitive SymNet Designer software that preceded it.
The remaining demonstration spaces, which include CEO Ron Callis’ office and the sales, creative team, engineering, and accounting offices, show off different combinations of acoustical treatment and loudspeaker, video, computer, and lighting technologies.
Posted by Keith Clark on 06/18 at 01:24 PM
Atlas Sound Debuts DSP2210 & DSP2212 Digital Processor And Amplifier
Atlas Sound DSP2210 and DSP2212 digital sound masking/paging systems are self contained, digital signal processors with integral amplification designed to efficiently route and mix masking, paging, and background music sources. Applications include speech privacy and general paging for office spaces, health care campuses and secure government facilities.
Masking source is completely random and non-repeating (up to 215) hours with EQ adjustments programmable per output zone. Both models include dual channel Class-D amplification rated at 25W/channel (@ 70.7V) and a built in telephony interface simplifies paging set-up.
The system is expandable up to (32) systems (64 zones) with primary and secondary assignment in a zone page dialing plan (2-digit DTMF) with “All Zone” and “Group zone” pages simply configured via the GUI. A powerful, fixed architecture DSP provides equalization, dynamic and routing priority control for all input sources as well as line level and amplified outputs.
Model 2212 includes AVB (Audio-Video Bridging) network interface allowing paging and BGM sources to be shared between multiple DSP8807’s or DSP2212’s.
“The DSP2210 and DSP2212 are the other two new products in the sound masking category that we are releasing this year”, said Steve Young VP of Sales & Marketing.
He continued, “the DSP2210 and DSP2212 are feature rich sound masking processors that can be used in small to medium applications. By themselves they are extremely useful but when the DSP2212 is used on the same network as the DSP8807 our integrators can truly handle any size sound masking application.”
Auralex Unveils QuadFusor Sound Diffusor At InfoComm 2012
At the InfoComm 2012 show in Las Vegas, Auralex Acoustics introduced the QuadFusor sound diffusor, combining four of the company’s MiniFusors and arrays them in an attractive 2-foot-by-2-foot pattern.
The Class A fire-rated acoustical diffusor is suitable for commercial spaces and can be dropped into a ceiling grid or mounted to a wall or ceiling.
The QuadFusor’s surface-variable design includes a proprietary ledge and rear cavity that accommodate the insertion of a rigid substrate such as Auralex PlatFoam or acoustical fiberglass, thus improving the device’s diffusion characteristics and adding significant low-frequency trapping.
The QuadFusor can easily be installed in new or existing construction. The QuadFusor is Auralex’s latest addition to their complete line of acoustical treatment solutions, perfect for contractors and system integrators at any budgetary level.
For more information, please visit .
BSS Audio Broadens Network Interoperability With Dante
In a move to broaden network interoperability of its category-leading Soundweb London audio networking and processing platform and provide integrators with more comprehensive choices, Harman’s BSS Audio today added Audinate Dante enabled processors to a line that also includes Cirrus Logic CobraNet and AVB.
As a result, Harman Professional and BSS Audio now provide deeper technology solutions and support for legacy projects, current large format fixed installations and progressive AVB-enabled networks in the pipeline.
The BLU-806 offers the same configurable signal processing capability as the existing BLU-800 device. Both new devices offer configurable inputs and outputs, compatibility with all Soundweb London input and output card options, logic processing capability, the 256-channel Soundweb London digital audio bus and GPIO.
Each device offers up to 16 inputs and outputs, configurable in banks of four. Card options include analog mic/line inputs with Phantom Power, analog outputs, digital inputs (AES/EBU and S/PDIF), digital outputs, the Soundweb London AEC Input Card and the Soundweb London Telephone Hybrid Card.
The BLU-806 and BLU-326 devices allow 64 incoming Dante channels and 64 outgoing Dante channels.
“System designers using Soundweb London will now have the choice of AVB, CobraNet or Dante as the digital audio transport, using the Soundweb London digital audio bus to complement the application-specific transports. Most importantly, system designers are able to deploy each of these transports using a single software application,” stated Iain Gregory, Marketing Lead for Installed Sound at Harman Signal Processing.
The BLU-806 and BLU-326 along with the other members of the Soundweb London family provide the building blocks of the perfectly tailored system solution.
Extron Now Shipping HDCP-Compliant HDMI Fiber Optic Extenders
Extron Electronics is pleased to announce the immediate availability of the FOXBOX HDMI fiber optic transmitter and receiver set for long haul transmission of HDCP-compliant HDMI video, audio, and RS-232 control signals over fiber optic cabling.
Engineered for reliability and exceptional high resolution image performance, the fiber optic transmitter and receiver use Extron-exclusive all digital technology to deliver pixel-for-pixel performance with signals up to 1920x1200, including HDTV 1080p/60. Available in multimode and singlemode models, FOXBOX HDMI products include Key Minder, EDID Minder, Auto Input Memory, RS-232 control from multiple locations, internal test patterns, and real-time system monitoring.
EDID Minder manages EDID communication and Key Minder supports continuous authentication of HDCP compliance, providing enhanced and simplified integration. Compact, low profile enclosures allow for discreet installation such as behind a flat-panel display.
“AV system designers have been attracted by the multiple benefits of fiber optic signal transmission, and now they have a solution for transmitting protected HDMI content,” says Casey Hall, Vice President of Sales and Marketing for Extron. “FOXBOX HDMI fiber optic transmitters and receivers ensure perfect pixel-for-pixel accuracy over extended distances.”
FOXBOX HDMI transmitters and receivers can be used in combination with FOX Series matrix switchers to create HDCP compliant signal distribution systems up to 1000x1000 and larger, supporting enterprise installations with fast and reliable switching. In addition, they are compatible with FOX Series VGA and DVI extenders when transmitting non-HDCP content.
Units can be paired with FOX Series VGA transmitters and receivers for easy conversion between RGB and HDMI in AV systems that include a variety of analog and digital displays and sources. FOXBOX HDMI is ideal for a wide range of applications requiring long distance transmission of high resolution content with the highest quality.
Posted by Keith Clark on 06/18 at 10:26 AM
Carl Tatz Design Chooses Argosy Dual 15 For New Village East Studio
Village East, the personal mix room of renowned multi-platinum/Grammy-winning engineer/producer Bob Bullock, recently came online showcasing the world-class performance of the Carl Tatz Design PhantomFocus System monitor tuning protocol, as well as a number of performance and design elements hand-picked by Tatz, including the Argosy Dual 15 DR 800 studio workstation.
Bullock, who has engineered and mixed for artists such as Reba McEntire, George Strait, Travis Tritt, and Shania Twain, realized that with the caliber of his client work, he needed a personal studio environment which could sonically and aesthetically rival any high-end studio, and called on personal studio guru Carl Tatz to design it.
Tatz chose the Argosy Dual 15 DR 800 studio workstation to be the centerpiece as Bullock’s control surface and to compliment his acclaimed PhantomFocus System tuning.
“My workstation of choice for engineers working in the box, which may be a majority nowadays, is the Argosy Dual 15 with the 800 rack modules, “ says Tatz. “It has a minimum monitor reflection architecture and handsome silhouette making it the perfect complement to the PhantomFocus System.”
Along with the new Carl Tatz Signature Series by Auralex turnkey acoustical treatment system that emulates the design and performance of Tatz’s custom-designed control rooms, he also employed Dynaudio Professional M1 reference monitors driven by a Bryston, 4B SST2 power amplifier.
“When I design a studio, I choose partners who understand my vision and the standard for design and performance of the PhantomFocus system,” says Tatz. “I use elements which are both aesthetically pleasing and high performing.
The Argosy Dual 15 DR 800 has the slanted back and I love the way it looks – it takes the control room to a serious level in terms of design. And it provides the perfect positioning environment for the sweet spot.”
The Argosy Dual 15 DR-800 has a sleek, symmetrical design, featuring a front desk area and two 15-dgree angles for a wrap-around feel. The Dual 15 features two DR 800 rack modules, with a slanted top to defeat early reflections. The Dual 15 is designed to enhance the studio workspace by bringing essential order to all the equipment, putting all the controls within easy reach of the busy engineer. A padded armrest offers comfort for long studio sessions.
According to Tatz, all the manufacturers that he worked with on the project can share in the stunning results at Village East. Now music professionals can have a truly state-of-the-art mix room second to none at an affordable price point.
“The PhantomFocus System and all of its manufacturer partner elements made it possible to implement a world-class studio in a bedroom,” adds Tatz. “Bullock’s Village East is a tremendous showcase of what is possible nowadays. The room design is gorgeous, the monitoring is superior, and Bob and his clients can feel confident here knowing that it has the acoustics, monitoring, and vibe of a peerless mix room.”
Posted by Keith Clark on 06/18 at 10:16 AM
Saturday, June 16, 2012
Allen Products Debuts Updated Ceiling & Wall Mounts At InfoComm 2012
Allen Products rolled out several updated ceiling and wall mounts at InfoComm 2012, including the Steerables Wall Mount, Adjustable SocketMount, Adjustable U-Bracket and several MultiMount solutions.
Steerables Wall Mounts suspend and aim loudspeakers, equipped with suspension or mounting points, from walls and other vertical structures. Users can make or remake pan-and-tilt adjustments within seconds, offering unprecedented ease and precision.
Designed for use with permanently installed loudspeakers in churches, schools, gymnasiums, auditoriums, theme parks, nightclubs, and bars and restaurants, Steerables Wall Mounts feature a unique cross-arm steering mechanism providing up to 360 degrees of pan control. Their structural steel alloy assembly is coated with a baked-on black textured powder coat finish.
Steerables Wall Mounts can support loads of up to 100 pounds./45.5 kg. with a 5:1 safety factor. In addition, tilting can be achieved with Allen Products’ U-Series bracket or the Steerables Tilt Cable Kit.
Allen Products Adjustable SocketMount supports and aims loudspeakers that are equipped with pole sockets to walls and other vertical structures. Both pan and tilt rotations are provided for optimum aiming, and the support arm folds down when not in use.
The Adjustable SocketMount is designed as a temporary solution, as its easy-on, easy-off feature allows loudspeakers to be relocated to other SocketMounts and/or tripod stands, thus reducing the need for additional loudspeakers and saving floor space.
Adjustable U-Brackets mount loudspeakers quickly and reliably to walls and poles, and from under ceilings, balconies, overhangs and other structural mounting surfaces. These brackets give installers multiple options for mounting speakers to irregular or unpredictable mounting surfaces due to their unique mounting pattern.
Allen Products Steerables Wall Mount. (click to enlarge)
Adjustable U-Brackets support most of the mountable loudspeakers in the 60 lbs./22 kg. range, or less, and their open side-arm slots allow a single installer to easily mount loudspeakers in this weight range. Loudspeakers rotate within the arms of the U-Bracket kit to aim sound toward the audience. It then locks into position, with the included friction washers and compression hardware.
Allen Products also introduced several updated models of MultiMounts at this year’s show, including its MultiMount MM-120, MultiMount MM-024 and MultiMount MM-020-CM.
• The MultiMount MM-120 pan-and-tilt speaker mount is a sturdy and adjustable speaker mount that is safe and exceptionally easy to use for installing large-format loudspeakers. It accommodates up to 120 lbs. with greater than a 5:1 design factor. The speaker brackets’ mounting holes match two standard speaker mounting hole patterns, the 6.88- x 3.44-inch and the 2.75- x 5-inch, and two VESA mounting hole patterns, the 75- x 75-mm and the 100- x 100-mm.
The bracket’s pivot housing provides 65 degrees of tilt adjustment and the screw-drive thumb-wheel adjustment makes tilting speakers very stable. The pivot housing also provides a full 180 degrees of pan rotation. A clutch-style lock holds it in position. The wall bracket accommodates stud mounting with two centrally located mounting/alignment holes and a slot that allows for plumb adjustment. Four outer holes allow it to be secured to other structural surfaces.
• The MultiMount MM-024 supports loudspeakers weighing up to 60 lbs./27 kg, enabling the quick attachment of them to walls, ceilings, overhangs and other structural surfaces. Speakers can be aimed and locked in almost any direction or angle through the use of independent pan, tilt and clockwise adjustments. MultiMount-024 supports vertically oriented standard speaker mounting-hole patterns.
Tilt adjustments are made independently at the side of the speaker adapter plate. Panning adjustments are also made independently at the mounting plate and a third rotation is available between the speaker and the support arm. This rotation is especially useful in directing sound from the ceiling and under balcony applications, where mounting space is limited.
• MultiMount MM-020-CM is specially designed to suspend loudspeakers (weighing up to 60 lb./27 kg.) from overhead structures using a customer-supplied schedule 40, one-half inch NPT pipe. This allows the installer to bring the loudspeaker down from any height, positioning the speaker closer to the audience, further reducing the speaker’s size and power-rating needs. The MM-020-CM provides a very clean loudspeaker installation because signal wire and safety cables can be passed through the pipe from the ceiling to the speaker’s terminal block without being seen.
Also, this design adapts directly to standard loudspeaker mounting-hole patterns so no modifications are necessary. The oval-shaped ceiling attachment plate offers a sufficient mounting surface with four one-quarter inch mounting holes to secure to overhead structures including beams, beam clamps, etc. Pan-angle adjustments are achieved where the MultiMount and the vertical tube (pipe) connect, with down-tilt adjustments at the mount’s two-side clutch-lock points.
“We are thrilled to present an expanded line of ceiling and wall mounts at this year’s show,” says Paul Allen, president, Adaptive Technologies Group. “Allen Products provide a wide range of standard and custom mounting solutions to cater to nearly every possible configuration request. We will continue to develop new products based on our customers’ feedback.”
Adaptive Technologies Group combines the efforts of Allen Products, ATM Fly-ware and Adaptive Video Walls and Displays, and offers rigging and mounting solutions for a wide range of audio and video applications. Each brand offers its own standard and unique time-saving solutions, plus unlimited custom products for any venue or application. Based in Signal Hill, California, all overhead products and parts are made and assembled in the USA.
Adaptive Technologies Group
Posted by Keith Clark on 06/16 at 12:26 PM
Friday, June 15, 2012
Consultants, Contactors, Retailers - And Your Church Sound Project
Many churches don't see the wisdom of paying for professional help with sound system needs, too often to their own detriment
When faced with a need for either a significant improvement to an existing sound system or an entirely new sound system, the most often-heard advise is “hire a qualified consultant.” Or at least it should be.
But many churches balk at the notion of paying a fee to a professional to help with sound system needs.
The thinking: this is not money well spent because there always seems to be “someone” in the congregation confident in his own abilities to choose appropriate equipment and put it all together. Or, the local music store will provide the required expertise - why pay anyone else?
These approaches have lousy track records, wasting buckets of money and making everyone involved with the church suffer through poor sound quality for years. And years…
Full disclosure at this point: I am a long-time electro-acoustic consultant, so there might be temptation to think I’m biased in dispensing advice.
But the reality is that I truly wish I didn’t have to address this topic, because I’ve spent my career trying to help churches pick up the pieces after they’ve suffered mightily by putting their trust in totally unqualified personnel.
The bottom line is that a qualified consultant who specializes in live sound reinforcement (because this is what a church sound system is designed to do) will end up saving the church money, time and a whole lot of heartache.
Sound systems may be obtained in three basic ways:
1) All at once or piece-meal from a retail outlet (music store) or catalog vendor, usually installed by church members.
2) All at once or piece-meal from an AV contracting (“design-build”) firm that usually does at least part of the installation as well.
3) All at once with design by a qualified consultant and installation by a contracting firm that both work as colleagues in the process.
New let’s clarify these sources and what they do.
A retail supplier or catalog house that sells professional audio equipment does not design or engineer sound systems, and in most cases they’re not qualified to do either. All but a few of the largest do not employ seasoned live sound system experts. Very few, in fact, have staff with significant experience in live sound system design or operation.
Staff members are primarily part-time musicians or home studio owners who are there primarily to supplement their incomes. And musicians and home studio people are rarely qualified to provide sound reinforcement design advice, nor do they usually have a grasp of architectural accommodation, nor do they possess the necessary skills in installation and related safety issues, nor electrical systems and related issues, nor the physics of electroacoustics.
Further, they’re not familiar with the National Electrical Code (NEC) that must be adhered to, both for inspections and insurance purposes.
Usually, they can’t properly employ room and system modeling (computer-assisted prediction), and they’re not trained or invested in test and measurement skills/equipment that help truly optimize a sound system.
They’re usually not members of any pro audio and/or acoustics trade organization, and they’re also prone to dismiss many significant issues as “not that complicated.” (And if you hear someone say this, run away screaming immediately!)
Note that I am saying most - not all - fit these criteria. Anyone still bold enough to tread down this path should at least understand the right questions to ask.
A contracting firm usually specializes at installing systems, and many also offer system design services. However, be aware that this does not necessarily mean that they’re qualified to design systems.
Some have invested time and money in modeling and optimization training and equipment, and also have the necessary experience in using these tools and others to do successful design work.
But others, even with training, may be lacking the necessary design skills, whether it’s due to lack of experience and/or other factors. (Do you really want someone learning how to design when it’s your system?)
In other words, just because someone shows you a technical document on a computer screen - and goodness, it does look complicated - does not mean the document is providing any salient information that will translate into a better sound system design. Or, that the person doing the showing knows much more than you.
This is a common sales tool that is used to show off and “wow” the customer, when in reality, there might be little depth of knowledge and understanding behind the “dog and pony show.”
Further, contracting firms are increasingly focused on selling total audio-visual (AV) system packages, encompassing not just sound but also lighting and video. As a result, the emphasis is not just on sound, with staff members sometimes not likely to possess deep knowledge on the subject.
Like retail outlets, no single contracting firm can carry all lines of audio equipment, and they’re also bound by agreements with manufacturers to sell certain amounts of each brand they carry.
They’re also not prone to attend your project meetings without additional fees, and other than a complimentary site visit, they’re also not likely to budget time for programming and design development. They usually don’t make provisions for the focused, useful training of volunteer sound operators on aspects such as the “how and why” of live sound, as well as mixing, politics and so on.
Better contracting firms will have licensed engineers on staff, and they make it a practice to send staff members to seminars, workshops and other continuing educational endeavors. Further, these firms belong to respected trade organizations such as the National Systems Contractor Association (NSCA) and the Audio Engineering Society (AES).
There is one caveat to be pointed out. Some contracting firms offer true system design-build services, and they employ qualified designers, either on staff or via a business arrangement. This approach and structure has proven successful in some situations.
The bottom line is to understand what a contactor can and cannot do - again, if you simply ask the right questions.
A qualified electroacoustic consultant will offer ample experience working with and designing sound systems for churches, and often, other performance spaces. They will have attended advanced live sound related seminars and workshops, and they continue to do so because this is their specialty.
Consultants may or may not have licensed engineers on staff, but will have a firm grasp on safety issues, and are familiar with the terminology and methods employed by architects, other consultants (theater, acoustics), specialty engineers (electrical, structural, mechanical), and contractors (carpenters, electrical, HVAC, etc.).
Qualified consultants will also have worked at various times for a church or performance venue as staff sound system operators. Often they will have a background in contracting, and should have some background in music as well.
They will have membership with organizations such as NSCA and AES, as well as the ASA and USITT, and it is not uncommon for some staff to be trained as professional engineers (this is designated by a “PE” in their titles on business cards.)
They attend several trade shows each year because it provides insight into emerging technologies and new equipment, and it also allows them to attend technical papers and to sit in on technical committees. Participating in these conferences keeps the consultant “connected” and helps to prevent them from becoming either too proprietary or experimental.
To The Chase
One of the most significant issues: the consultant is employed directly by the client to provide the best possible system design at a reasonable cost. (It’s under the category of “who’s looking out for number one?”)
As a result, consultants specify equipment based upon its merits and value. Their affiliation with manufacturers is one of mutual respect and not unduly influenced by numbers. This independence is paramount.
However, many consultants are asked by manufacturers to participate in product development, or to provide valuable feedback so that minor design flaws may be corrected. (The better contractors and design build firms do this as well.) All must walk the lie between incorporating new products/technologies and undertaking unnecessary risk for every system project.
Consultants must also participate in your project meetings, and at the end of the design phase, they deliver a completely engineered audio system design in the form of a bid package, plus a list of pre-qualified contractors to bid on the project.
The specification should allow very few items that the bidding contractors are allowed to substitute. Specifying exact equipment for all but the most mundane components of a system is what the consultant is paid to provide, and the consultant should be able to clearly detail to the client why each device is required.
One other aspect of a complete system design is provision for future needs. This may take the form of recommending more mixer input channels than are initially needed, additional wire, cable and conduit (installed at the outset even if they’re not needed until later), and a digital processor that can easily be expanded in functions and input/output capabilities. This can save thousands and thousands of dollars down the line.
Finally, the design package should be complete and not require the contactor to “fill in the blanks.”
Another valuable ingredient is the bidding part of the process itself. If a church attempts to shop around for a sound system package, not only is this very likely to lead to multiples of package proposals (these are not designed systems in any way, shape or form), but prices will vary widely.
All of this leads to chaos since there is no way to qualitatively compare the multiple proposals.
Aside from confusion about what the church is really buying, this also opens the door to temptation to accept a lower quality system based solely on dollar value.
A consultant designs the appropriate system and estimates what it will cost. If this is too much money, then the consultant may be able to provide a lower cost option, and with a full explanation of the ramifications.
Note, however, that consultants must be willing to say “no” when being pressured to provide a compromised design, and if necessary, they will walk away from a client with unrealistic expectations.
Another option is to stage the system purchase and installation into several phases, allowing the client to obtain the best system over time. But note that this is still a “system” design and not a piece-meal approach.
As part of the bid package, the consultant provides a list of several pre-qualified contractors and they bid on the same system design. This results in no ambiguities, and the client can then accept the lowest (or one of the lowest) bids.
Programming is the most important first step in developing a design that provides what is needed. The consultant must also attend worship services and interview key personnel to establish what their needs and hopes are. This also helps the consultant to identify the technical capabilities of the crew.
Following programming and the various design phases (schematic design, design development), the entire sound system design must be presented in the form of contract documents, which include drawings and a written specification.
The drawing set must include the functional aspects of each part of the system, as well as detailed drawings of key components such as loudspeakers (clusters, arrays, rigging and mounting methods), rack elevations, custom panels, and the isolated ground AC (electrical) power system.
The latter is provided as a concept (because consultants are not licensed to engineer them), and then it must be approved, detailed and stamped by a licensed electrical engineer in the local where the church is being built or the system is being installed. This is also the case for any suspended devices such as loudspeakers.
Once the contracting firm is selected, the consultant serves as the primary interface on all issues related to the system, and then interfaces with the client on any aspects of note.
Yet another important part of the services provided by a consultant is an ability to measure and optimize the system after it is installed, and then to train the users in its operation. This completes the picture.
Finally, the consultant will be available to answer questions later, as they crop up, which can inevitably happen with a new sound system.
Churches that invest the time and care in finding and vetting qualified candidates for design and install services are much more likely to achieve a sound system that serves their needs, and will do so for many years to come, while also receiving a very high return on their investment.
Audio-Technica Introduces New Components For SpectraPulse Wireless System At InfoComm 2012
Audio-Technica has introduced two new components for its SpectraPulse Ultra Wideband (UWB) wireless microphone system.
The new chg004 is a four-bay charger for SpectraPulse transmitters, while the new sei001 encryption interface is now included with the optional encryption software available for the SpectraPulse system.
The new chg004 offers four charging bays that hold either mtu101 microphone transmitters or mtu201 XLR desk stand transmitters; the unit is also designed to charge up to two mtu301 bodypack transmitters.
Supplied rechargeable AA Nickel Metal Hydride (NiMH) batteries are charged within the SpectraPulse transmitters. The chg004 offers built-in safety features that monitor cell voltage and automatically stop charging if problems are detected or if alkaline (non-rechargeable) or damaged batteries are installed.
Maintenance charging prevents battery self-discharge until the transmitter is removed from its charger. The package includes the chg004 charger, 12 NiMH AA batteries, two charging cables (for charging mtu301 units), a wall adapter power supply and an installation/operation manual.
SpectraPulse systems offer exceptional immunity to eavesdropping, and are available with optional sep128 encryption software that meets the AES 128-bit encryption standard developed by the U.S. government for securing sensitive material.
The sep128 software now comes equipped with the sei001 encryption interface, a convenient one-bay encryption station for SpectraPulse transmitters.
The first commercial sound implementation of Ultra Wideband technology, Audio-Technica’s SpectraPulse Ultra Wideband wireless microphone systems offer secure wireless operation for the installed sound market, free from RF competition, frequency coordination and “white space” issues.
These new components are part of Audio-Technica’s contractor-exclusive Engineered Sound line and will be available July 2012.
Posted by Keith Clark on 06/15 at 08:28 AM
Straightforward Approach To Setting An Optimized Audio System Gain Structure
Over the years I’ve seen many haphazard approaches in establishing gain structure through a sound reinforcement system.
Often rough adjustments can be made to make the problem less apparent, because gain is easily and cheaply available in today’s industry.
Years ago, when a 100-watt power amplifier was used to power the main loudspeaker system, gain structure was a critical issue. Today, with the advent of amplifiers that can output levels of 1,000 watts or more per channel, proper gain structure can be easily overlooked as a critical element in the performance of a system.
Powerful amplifiers, however, are not an excuse for an individual to lack a firm understanding of proper gain structure. Many of today’s signal processors and amplifiers have jumpers, switches, or knobs that, if adjusted properly, will maximize the systems signal to noise ratio while also ensuring the system will safely operate at the levels that are required.
First we’ll determine how much gain is required throughout the system, from the console to the listener. Then, once overall gain requirements are known, we can discuss the approach to setting the system’s gain structure.
How much gain is enough?
A good designer will always have an established sound pressure level (SPL) criteria for each system in which he/she is working on. Without this pre-determined resultant SPL, you may often find yourself over or under specifying the total gain required in a system.
So, let’s establish a criteria for the purpose of discussion. We will assume that we are designing a sound system for a church that has a contemporary music program. During the music portion of the program, it is anticipated that peak levels in the room need to reach nominal levels of 95 dB SPL, with peaks of 101 dB. It is also the intent to provide 10 dB of headroom. Our design criteria is now determined, and we can begin our discussion of gain structure.
The first thing to determine in the system is the amount of loss due to distance. For the purpose of our example, let’s assume that the furthest distance a listener will be from the speaker is 80 feet. Because sound radiates spherically, the attenuation is proportional to the square of the distance from the source, and thus there is a 6 dB reduction for each doubling of distance.
Assuming that the sensitivity of the loudspeaker is given in reference to 1 meter, this can be represented mathematically by the equation:
(Equation 1) SPLdist-loss = 20 log (distance in feet / 3.3)
The 3.3 factor is used to convert feet to meters. Using this equation, we determine there will be a total loss of 28 dB as a result of distance. We can now calculate the maximum output level of the loudspeaker that we will require in order to achieve our design criteria.
We have already determined that we need a maximum SPL level of 111dB at the listener position (101 dB peaks with 10 dB of headroom). At the loudspeaker we will need a maximum SPL level of 139 dB (111 dB at the listener position + 28 dB of loss due to distance.)
The selection of the loudspeaker is the next step in the process. Any loudspeaker that is specified will have a sensitivity and a maximum power rating. The sensitivity is normally given in dB SPL at 1 meter when a 1-watt signal is applied to the input of the loudspeaker, and is usually given in AES watts.
This AES measurement is a clearly defined standard in which a band of pink noise from 125Hz to 8Khz, with +6 dB peaks, is applied to the input of the loudspeaker for a period of two hours. Any loudspeaker that has its power rating in AES watts can very easily handle short-term peaks of +6 dB above the AES rating.
The maximum output level at 1 meter away from a loudspeaker will be derived from the formula:
(Equation 2) SPLmax-AES = sensitivity + 10 log (AES power rating)
(Equation 3) SPLmax = sensitivity + 10 log (AES power rating) + 6
Any loudspeaker we select must have an SPLmax of at least 139 dB. We will take one particular manufacturer’s loudspeaker that has a sensitivity of 112 dB at 1 watt/1 meter. The high frequency component can handle 200 watts, AES. Using the equation above, we find that the SPLmax equals 141 dB. This loudspeaker will have the ability of achieving our design criteria.
To complete the design, we must choose the correct amplifier size for the application. Amplifier power ratings are given in watts, but unlike loudspeaker AES power ratings, amplifier power ratings are the upper limits and do not include any crest factors.
For the purpose of discussion, let’s assume that we have a 3-way loudspeaker system (loudspeakers with high, mid and low sub-sections), with the following AES power ratings and sensitivity ratings:
Loudspeaker Sensitivity & Power Ratings
AES power rating————————200————————-400———————-1000
(Using Equation 3)
The high and mid sub-sections of a single loudspeaker can handle the minimum SPL requirements of 139 dB at 1 meter. However, the low frequency sub-section will require two loudspeakers.
And then, by doubling the number of loudspeakers, we will obtain a +6 dB gain, which results in a low frequency peak SPL of 143 dB. We can now go directly to our amplifier selection. In order to calculate the amount of power required, we need to use the following equation:
(Equation 4a) PWR(dB) = SPL Criteria peak - sensitivity + SPLdist-loss
(Equation 4b) PWR (watts) = 10 PWR(dB)/10
The peak SPL criteria was established earlier at 111 dB SPL (96 dB nominal + 6 dB peaks + 10 dB headroom). The loss due to distance is 28 dB. By plugging these numbers into equations 4a and 4b (above), we obtain the following results:
Amplifier Power Requirements
Calculated Minimum Power———27 dB——————30 dB———————-32 dB
Power in watts**——————-500 watts—————1000 watts—————1585 watts
* One loudspeaker will be required to provide an SPL criteria peak of 105dB SPL since two loudspeakers will give us our required SPL criteria peak of 111 dB SPL.
** This is peak power, not AES. The AES power handling would -6 dB lower than this (divide by 4).
Now that the amplifier size has been determined, the next thing to look at is processing level inputs and outputs.
Most sound consoles can comfortably handle an output level between +18 dBu and +24 dBu.
This, in turn, will feed the processing equipment. Analog processors can usually handle +18 dBu input and output signals. This is the first place in line where attenuation or a pad may be required.
If you are using a console that can output +24 dBu, you will want 6 dB of attenuation at the input of the audio processor. This can usually be achieved by the input attenuators on the signal processor.
The outputs of the signal processors require a bit more discussion. Many DSP devices have either output switch settings or output jumper settings that can select between 0, +6 dB, or +12 dB, so the obvious questions are “Why are there different options?” and “When do you use them?”
To answer this, we must first continue our discussion about amplifiers.
AMPLIFIER INPUT LEVELS
Many manufacturers have input selection settings than can choose between 0.775V, 1.4V, X20 (or 26 dB), or X40 (or 32 dB). For the purpose of discussion, the table below indicates the input level that 200-, 400-, and 800-watt amplifiers will accept before the amp clips.
The 0.775V and the 1.4V input level settings indicate that all amplifiers will clip at the same input level. For the X20 (26dB) or the X40 (32dB) selection settings, the size of the amplifier and the load on the amplifier will determine the level at which the amp will clip. It is very important to be able to understand the clip levels and gains of the amplifiers in both dB and in voltage.
For 0.775V or 1.4V input sensitivity
(Equation 5a) Gain (volts) = sqrt [Max power rating * load (ohms)] / input sensitivity
(Equation 5b) (dB) = 20 log[Gain (voltage)]
(Equation 5c) Clip Level (volts) = input sensitivity (0.775V or 1.4V)
(Equation 5d) Clip Level (dB) = 20 log [clip level (volts)]
For X20 (26 dB) or X40 (32 dB) gain
(Equation 6a) Clip level (volts) = sqrt [Max power rating * load (ohms)] / gain (20 or 40)
(Equation 6b) Clip level (dB) = 20 log[Clip level (volts) / 0.775V]
(Equation 6c) Gain (volts) = gain (20 or 40)
(Equation 6d) Gain (dB) = 20 log[gain(volts)]
Amplifier Input Clip Levels
———————-200 Watts————————400 Watts————————800 Watts
X20 (26 dB)———-8.2 dB———————————11.2 dB—————————-14.2 dB
X40 (32 dB)———-2.2 dB———————————5.2 dB——————————-8.2 dB
0.75V——————0 dB————————————-0 dB——————————-0 dB
1.4V——————-+5 dB———————————-+5 dB——————————+5 dB
Now that we have thrown all of these numbers out there for you to ponder over, we now need to know when we would want to use these different input settings.
The primary factor in determining which settings to use is determined by the designer’s requirement for the system’s noise floor.
If noise floor is not absolutely critical (NC-25 or higher spaces), then the amplifiers can safely be set on 0.775 (or preferably 1.4V if available).
Because the actual gain of the amplifiers is quite high (~X40 for a 100 watt amp to ~X130 for a 2500 watt amp), the noise floor will be higher. The clear advantage, however, is that you do not need to calculate the attenuation needed for every channel of every amplifier.
If noise levels are a critical concern, then constant gain settings should be used, but you will need to calculate the attenuation for each amp channel.
To conclude our discussion on signal processing and the output level switches on DSP devices, if you are using an amplifier that has its input sensitivity set on 0.775V, then the output of the DSP should be set at 0 dB. This will provide 18 dB of attenuation between the console and the amplifiers.
If the input sensitivity of the amps are set at 1.4V, then the output of the DSP should be set at 6 dB. If you are using constant gain, then each output needs to be addressed on an individual basis.
One final note on gain structure worth mentioning is to always have a good sense for what is occurring with the system equalization. Let’s assume that there is a large +10 dB boost in the EQ at 8K.
During system tuning it may make the speakers sound very well and provide extended high end frequency response, but 8K signals will clip the amplifiers 10 dB sooner than the rest of the system.
Similar problems may arise from very large EQ cuts, but if at all possible, for gain structure purposes, it is better to cut than to boost, and it will always be best to keep your cuts and boosts to an absolute minimum.
Brian Elwell is senior consultant with Acoustic Dimensions and has contributed to system designs at major stadiums, houses of worship, theme parks and many other venues.