.(JavaScript must be enabled to view this email address)
Article
Loudspeaker
Wednesday, February 08, 2012
Tannoy Unveils VLS Series Passive Column Array Loudspeakers
Tannoy has introduced the VLS Series passive column array loudspeakers offering a balance of performance and cost, when active beam-steering may neither be required nor affordable.
The VLS Series is the first Tannoy product to incorporate FAST (Focused Asymmetrical Shaping Technology), which delivers unique acoustic performance benefits. Central to this is its asymmetrical vertical dispersion, gently shaping the acoustic coverage towards the lower quadrant of the vertical axis. By the nature of a typical application, an “ideal” column loudspeaker should be biased in the vertical plane, toward the audience and away from reflective surfaces above (like ceilings) which are detrimental to intelligibility.
FAST also facilitates quicker, easier installation with less need for tilting or specific concern for optimal mounting height. Mounting is handled via supplied wall brackets.
Tannoy has packaged this performance in a slender and narrow profile, aesthetically refined, powder-coated aluminum chassis with curvilinear aluminum grille. Each model is available in either black or white as standard, with custom RAL finishes available at additional cost and lead-time.
Three models are available – VLS 7 (7 × 3.5-inch LF) designed for speech-only applications, VLS 15 (7 × 3.5-inch LF with 8 × 1-inch HF) and VLS 30 (14 × 3.5-inch LF and 16 × 1-inch HF), both of which are designed for more demanding full-range applications as well as speech.
All are IP64 rated for dust and water ingress and are salt spray and UV resistant as well as subject to rigorous high/low operational temperature and humidity testing.
Specification is aided by the addition of an exclusive Tannoy edition of EASE Focus v2.0 software, allowing systems to be designed with predictable results, along with the ability to specify VLS Series in conjunction with Tannoy’s existing column loudspeakers – including I Series and QFlex.
Meyer Sound Promotes Miguel Lourtie To European Technical Services Manager
Meyer Sound has announced Miguel Lourtie as its new European technical services manager, where he will supervise the company’s technical support team in Europe and assume primary responsibility for sales support and design services in the region.
“Customer support is paramount at Meyer Sound,” says John Monitto, Meyer Sound’s director of technical support worldwide. “Our customers expect an extremely high level of technical expertise and customer service. With his outstanding technical skills, customer rapport, experience in the field, and fluency in several languages, Miguel is a great fit to lead our technical group in Europe.”
Lourtie joined Meyer Sound European technical services in 2007, and has played a vital role in supporting a number of major Meyer Sound projects across the continent, including the Mantziusgården Culture Center, Montreux Jazz Festival, and the Grimaldi Forum. He also serves as a seminar instructor as part of Meyer Sound’s extensive education program.
Prior to joining Meyer Sound, Lourtie founded Lourisom, an audio consulting and distribution business in Portugal and previously a Meyer Sound distributor.
“To ensure a seamless show, high-quality audio tools and the person driving the system are equally crucial,” says Lourtie. “The Meyer Sound tech support network has some of the best sound engineers in the industry, and I look forward to working even more closely with them to help our customers get the best out of their Meyer Sound equipment.”
Lourtie will continue to be based in Lisbon, Portugal.
The Right Sonic Blend For An Electronic Ensemble & The New York Philharmonic
Reinforcing the live performance of a motion picture score at Avery Fisher Hall in Lincoln Center
The Philip Glass Ensemble, along with members of the New York Philharmonic Orchestra and the Collegiate Chorale symphonic choir, recently performed Glass’ powerful score for the 1982 landmark motion picture “Koyaanisqatsi: Life Out Of Balance” as the film screened at Avery Fisher Hall in Lincoln Center.
The two exclusive live performances (and screenings), held on consecutive nights for sold-out audiences at the 2,738-seat home venue of the Philharmonic, presented some sound reinforcement challenges.
The hall does not have a house system, yet the Philip Glass Ensemble, founded by composer Glass in the late 1960s to perform his experimental minimalist music, is always amplified when playing live.
As a result, Dan Dryden, long-time front-of-house engineer for the ensemble, worked with Audio Production Services of Amawalk, NY to design a reinforcement system to serve the unique needs of the event while fitting within the scope of the hall.
“With an event like this you want all of the instruments, acoustic and electronic, to sound like they belong together,” Dryden explains. “The sound system needs to be clean and consistent, in addition to being capable of covering the entire hall without impeding any stage site lines.”
He adds that, in general, he prefers the footprint of compact line arrays, and following a site review, decided that approach would work for this project as well. The choice was the compact RCF TT+ Series, with single arrays each comprised of 10 TTL31-A modules flown left and right, attached to the overhead stage grid.
A view of Avery Fischer Hall with the main RCF TTL31-A arrays flown to each side of the stage. (click to enlarge)
“When specifying systems for the ensemble I’m looking for smaller line arrays with flat frequency response,” explains Dryden. “These were perfect. The low-mid frequencies are rich and warm, and the coverage was excellent.”
The overall footprint of these arrays indeed was relatively miniscule, measuring just less than two feet wide by only about 10 feet deep. The self-powered, 2-way active line array modules are outfitted with a single-8-inch cone driver and three compression drivers feeding a horn with horizontal dispersion of 100 degrees. They proved capable of covering all four levels of seating (main and three balconies) as well as boxes.
“The arrays had no problem throwing all of the way to the back row of the top balcony without any need for delay fills. We had plenty of power for the space,” Dryden states.
The mains were joined by four RCF TTS56-A dual 21-inch subwoofers, two side-by-side on each side of the stage, and each of these sub sets hosted a single TT25 compact powered loudspeaker supplying in fill presence, particularly for higher frequencies.
The house loudspeaker complement was completed with front fill via four TT052-A low-profile 2-way loudspeakers deployed evenly along the front lip of the stage.
The ensemble, positioned centrally on stage, was comprised of eight players, including three on keyboards, three more on woodwinds, one soprano vocalist, and for this show, a bass vocalist. The orchestra’s 30-piece string section and 19-piece brass section, as well as the 40-member choir, resided in a semi-circle around them.
Each string instrument – violas, cellos and double bass – was outfitted with a DPA 4061 omnidirectional miniature clip-on microphone, while Sennheiser MD 421 II dynamic mics were stand-mounted for each trumpet, trombone, French horn, bass trombone and tuba in the brass section. Each two vocalists of the choir shared a Shure SM58 mic, also stand-mounted.
A closer look at one of the compact arrays that provided the advantage of a minimal footprint. (click to enlarge)
The ensemble feeds went directly to both front-of-house and monitor consoles, with Dryden manning a Yamaha PM5D board for house and Stephen Erb on another PM5D for monitors.
All of the orchestra and choir feeds (more than 80), meanwhile, routed to a DiGiCo D1 Live console. There, Dan Bora did a mix of the individual stems that were then supplied to the house and monitor consoles.
“One big challenge for a performance of this scale is the number of inputs,” Dryden notes. “In this case we decided to utilize a sub mix, which ended up being a very big job. Not only did Dan Bora have to make sure signal integrity and placement of each of the microphones were good, but the mixes provided to house and monitors were key to the sonic performance.”
All effects were supplied via the PM5D consoles with the exception of a Lexicon 300 reverb at front-of-house that Dryden likes to apply to certain passages or sections.
The ensemble on stage surrounded by the orchestra and choir during one of the performances of “Koyaanisqatsi.” (click to enlarge)
“The Lexicon algorithms are excellent,” he says. “I’ve used Lexicons forever – for me they’re the smoothest, best-sounding digital reverbs.”
Monitor engineer Erb fed mixes to 12 dBTechnologies DVX D12 powered 2-way loudspeakers that acted as stage monitors for the ensemble - keyboards, woodwinds, soprano vocal and bass vocal.
The strings, brass and chorus sections were served monitor mixes with stand-mounted dBTechnologies K70 multipurpose ultra-compact loudspeakers (also powered).
Dryden reports that the project produced the results he was seeking. “I think it’s always important to remember that you need to work with a room rather than try to impose your will upon it,” he concludes. “In this case, it’s a terrific room and, when equipped with the right system, it sounded fantastic. The musicians in the symphony and the chorus added so much to the ensemble’s performance. It all added up to a lot of fun.”
Julie McLean Clark is a writer and marketing consultant working who has worked in the pro audio industry for more than 15 years.
Community Delivers Sound Throughout New Salvation Army Kroc Center (Includes Video)
McDonald’s founders Ray and Joan Kroc were known for supporting a variety of charitable causes, and their legacy continues with a multi-billion dollar donation to the Salvation Army for the construction of several community centers in cities across America.
The latest Kroc Center, recently opened in North Philadelphia, is one of the largest facilities of its kind on the East Coast, with 130,000 square feet that includes a world-class aquatics center, fitness center, worship and performing arts facilities, café and culinary education center, as well as a wide range of programs for kids, adults and senior citizens.
Quality sound reinforcement was also a big part of the plan for the facility, explains Joe Zamborsky of RTS Unified Communications, which specified a selection of Community Professional Loudspeakers for the project, including R-Series, WET-Series and CLOUD6 in-ceiling systems to cover the pool areas, worship center, fitness center gymnasium and numerous other areas.
“In any major project like this one, there are a number of challenges,” says Zamborsky. Clearly, the project’s tight six-month schedule was a demanding one, as was the need to be exceptionally flexible in the face of numerous logistical challenges.
“On more than one occasion, plans had to be altered due to unforeseen surprises during the construction process. “The number one most important thing is communication,” he observes. “We maintained a daily, ongoing dialogue with everyone involved in the project, and that was key to our ability to keep things moving.”
The Community loudspeakers fit the bill on multiple levels, says Zamborsky, “particularly in the pool areas, which combined a tremendously reverberant environment with an exceptionally high humidity, the R-Series was the only choice. Not only do they look great, but they sound terrific.”
The competition pool area offered up additional challenges as well. “Aside from having to cover the pool area itself, we were tasked with creating a separate system to cover the stands, which are tucked away in their own alcove,” Zamborsky adds. “We chose the Community WET Series to cover that area, because they provided both a tight, focused coverage pattern and a high degree of intelligibility.”
Audio Video Electronics Implements Tannoy QFlex At St. Frances Basilica
Home to one of the oldest Catholic congregations in the United States, the Cathedral Basilica of St. Francis of Assisi is sometimes referred to as the heart of Santa Fe, and for good reason. Although the Cathedral Basilica was dedicated in 1887, the site has been a focal point of worship for the community since 1610.
The first church built where the current structure now stands was destroyed during the Pueblo Indian Revolt of 1680, but another was built to replace it in 1714; a portion of which still stands within the existing building – a small adobe chapel dedicated to Our Lady La Conquistadora housing the oldest representation of the Virgin Mary in the nation.
In addition to serving the spiritual needs of it’s own congregation, the Cathedral Basilica’s rich history attracts approximately 100,000 visitors annually. As beautiful as the Cathedral is, however, for some years it has had a problem, says Wanda Vint, Director, Development and Donor Relations at the Cathedral Basilica. Put bluntly: “You couldn’t clearly hear the word of God.”
With the August 2011 installation of a state of the art sound system that depends heavily on a pair of Tannoy QFlex digitally steerable column arrays that’s all changed.
The major thrust behind the project was a 2009 visit made by the Cathedral’s Rev. Monsignor Jerome Martinez y Alire to the Basilica of Saint Mary in Minneapolis. Surprised that such an old and similarly acoustically reverberant space could sound so good, he asked who had designed and installed the system and was referred to Minnesota-based, Audio Video Electronics (AVE).
The project that initially caught the Monsignor’s ear was undertaken before QFlex was available, explains Kevin Crow, AVE’s VP of sales and marketing, but both spaces had similar issues: “In the Cathedral Basilica of St. Francis of Assisi, the RT was 5 to 6 seconds in the mid frequency band.”
In order to meet the Cathedral Basilica’s needs, Stefan Svard, AVE President and system designer, specified a pair of Tannoy QFlex 40s. Placed on a pair of columns roughly 6 feet above the floor just in front of the altar, the QFlex provide coverage to approximately 75 percent of the 1200-capacity, 90 - 65 foot space. They also provide low frequency support throughout the nave, the south transept, and the Our Lady La Conquistadora chapel.
Additionally, smaller Community Entasys arrays were installed as rear fills for the nave, and to provide reinforcement for the chapel and other ancillary spaces.
Basic EQ, tuning and system commissioning was done via Tannoy’s proprietary VNET software, with the processing handled by the onboard DSP within each QFlex, Svard says, but the system also incorporates a Lectrosonics Aspen DSP to handle mic mixing for the Earthwerks FM series podium condenser microphones specified by AVE, and matrixing for both the QFlex 40 and the additional fill speakers. The Lectrosonics Aspen is controlled by an iPad, which allows users to adjust volume levels easily depending on the type of service in progress, how much of the space is in use and the number of congregants present at any given time.
Naturally, the Cathedral Basilica’s atmosphere had an impact on the choice of QFlex, as did the ability to diagnose any issues the church might have using the QFlex array’s remote monitoring capabilities. But the main reason for choosing QFlex, Svard says, was experience. When he first heard QFlex he was cautious in his assessment. After a shootout with a competitor’s product in a St. Cloud, Minnesota house of worship, however, his opinion changed.
“We’ve done a number of Catholic churches, going back 6 or 7 years, using various steerable array products. Every product has strong points and weak points, but in that case, Tannoy’s QFlex was the clear winner.”
“If I’m in the front, middle or back of a room, the EQ that I need to correct is the same,” he continues. “Other products I’ve used shift in character. QFlex is the only product of its kind that retains its frequency response – its spectral consistency – across its coverage pattern.”
The result is a dramatic improvement in speech intelligibility and the sound quality of both background music and live performances by the Cathedral Basilica’s choir. Still, Vint was concerned some parishioners would not welcome the technology, particularly those who were uncertain they needed a new system, or that it might detract from the church’s historic atmosphere. “But the sound is so clear, we haven’t had any complaints at all.”
Monsignor Jerome Martinez y Alire is equally satisfied: “The sound quality is incredible, as is the appearance of the loudspeakers themselves. We were concerned about how modern speakers would look in such an old, historic church – with custom paint finish to match our walls they all but disappear. The clear, audible sound is a gift to our parishioners and visitors alike.”
Peavey Debuts Expansion Modules For Powered Loudspeakers
New Peavey Expansion Modules expand the capabilities of the company’s EU Series, Impulse 12D, and the new PVXp powered loudspeakers.
The new 9-Band Graphic EQ Expansion Module aids users in controlling feedback using the built-in, proprietary FLS Feedback Location System, which makes accurate feedback elimination simple and intuitive.
The 9-Band module gives users greater control over shaping and accenting live or recorded vocals and live instruments, as well as increases control over general sound equalization, and removes 60 Hz AC hum.
Meanwhile, the new 3-Band Parametric EQ Expansion Module provides fine-tuning capabilities with gain, frequency and bandwidth (Q) control.
Finally, the new 3-Channel Mixer Expansion Module expands the powered enclosure’s input options by three input channels, with each channel featuring level control, high and low equalization control, and a combination XLR and 1/4-inch input.
9-Band Graphic EQ Expansion Module specifics: —Nine frequency bands: 63, 125, 250, 500, 2k, 4k, 8k, 16kHz —FLS Feedback Locating System —+/- 15 dB boost and cut —U.S. MSRP $59.99
3-Band Parametric EQ Expansion Module specifics —Three frequency bands: Low 40 to 800Hz; Mid 200 to 4kHz; High 1kHz to 20kHz —+/- 12 dB boost and cut on each frequency band —Q adjustable from 0.1 to 1 on each frequency band —Hard-wire bypass —U.S. MSRP $49.99
3-Channel Mixer Expansion Module specifics —Three channels of additional inputs —Combination XLR female and ¼” TRS input —Microphone and line-level input range —Two-band EQ on each channel —Switchable phantom power global for all three channels —U.S. MSRP $79.99
The new Peavey Expansion Modules for powered loudspeakers are made in the USA will be available in Q2 2012 from authorized retailers.
Oslo Audio First Rental Company In Norway To Invest In L-Acoustics KARA
Oslo Audio has become the first rental company in Norway to invest in L-Acoustics KARA WST line source loudspeakers, ordering 24 cabinets from local distributor Scandec Systemer.
The KARA loudspeakers are powered by L-Acoustics LA-RAK amplified controllers and supplemented with SB18 subwoofers.
“KARA has a flexibility that will enable us to use the system for pretty much all venues in Norway,” says Paal Klaastad of Oslo Audio. “For us the audio performance of the KARA system was never in question. As a long-time L-Acoustics user, we are confident that the sound quality is first class. The reputation of the brand ensures that the end users are also confident of the system’s performance.
“The scalability of the system, its integration with the LA-RAK platform and the ease of rigging and handling makes us confident that this will provide a good return on investment for years to come. We look forward to putting the system to use, and to collaborating with other network agents in Scandinavia.”
Oslo Audio’s new KARA loudspeakers were used for the first time at the 10-year anniversary concert of Crystal Canyon Studios, with a lineup of Kåre & The Cavemen, Ulver, Paperboys, Kitchie Kitchie Ki Me O and André Holstad.
That system consisted of the 24 KARA cabinets with 12 SB118 subs and six 115XT HiQ coaxial monitors, powered by LA-RAKs.
AED Rent First Adopter Of JBL Professional VTX VT25 Line Array Loudspeakers
Belgium-based AV rental system provider AED Rent has signed on as the first adopter of the just-introduced JBL Professional VTX V25 line array loudspeaker, as well as a strategic partner in the VTX Network.
AED Rent is known in Europe as a market leader and a total system provider.
“Our mission statement is quite simple: To develop and maintain a flexible group of companies on a Pan-European base that offers a total solution for the professional in the AV industry,” says Glenn Roggeman, CEO of the AED group. “AED Rent is not just a rental company but an equipment bank, not only in sound, but also in lighting, rigging and video equipment. What makes this business quite unique is large quantities, industry standards, state-of-the-art products, and a young rental fleet with fast and accurate service.”
“We chose to purchase the JBL V25 because I think JBL has it spot-on for the future,” he adds. “JBL has always been known as the best component builder. Today, thanks to Paul Bauman, they not only have the components, but also the speaker boxes to make a terrific system.”
The VTX V25 is a full-size, 3-way, high-directivity line array element. The VTX V25 features two 2000-watt, 15-inch Differential Drive woofers mounted in die-cast aluminum baffles, with four 8-inch Differential Drive mid-range transducers and three of the revolutionary new D2 dual-diaphragm dual-voice-coil compression drivers mounted on a 3rd generation waveguide and patented RBI Radiation Boundary Integrator assembly.
“The technology JBL is using in the V25 is on the cutting edge,” Roggeman states. “If you see how much power the system is driving, it’s way above any competition. If you see the weight of the cabinets—82 kg—this is another attractive element, because in the future, environmental issues will play a bigger role in our business. A cabinet of 110 kg that needs to be transported will be more expensive than a cabinet of 82 kg.”
“We are thrilled that AED Rent has chosen to support the groundbreaking VTX V25 product,” says Paul Bauman, senior manager, Tour Sound, JBL Professional. “AED Rent’s technical expertise and leading position in the industry will be tremendous assets in our introduction of the V25 to the market.”
Soundworks Installs db Technologies In UW-Stevens Point Arena
A basketball arena at the University of Wisconsin - Stevens Point has been decked with 20 db Technologies Arena 15 loudspeakers. Beside sporting events, Quandt Fieldhouse is also the venue for commencement ceremonies and hosts a multitude of concerts and assemblies—which can ask a lot of the sound system and the design/build team.
Brian Baumann and Kent Laabs of Soundworks Systems Inc. handled the design and installation.
They explain, “The audio system needed to be capable of high SPL’s for UWSP Pointer basketball games and other athletic events. It needed to be capable of clear music reproduction whilst maintaining high speech intelligibility for both low and high SPL events. On top of all that, budget was a factor.
“The room itself presented acoustic challenges which included its mezzanine type area with tiered seating and a plexiglass-faced guard rail system. We needed to mitigate unwanted reflections from the maple floor, painted block walls and especially the plexiglass. We divided the room into 8 zones in order to accommodate the permanent seating, temporary bleachers and floor seating with delay and zone presets.
“We researched various loudspeakers from multiple manufacturers before deciding on the db Technologies Arena 15. We had used other Arena series products on previous installations and were familiar with their performance. We designed and bid the system utilizing the Arena 15 based on the available horn pattern, sensitivity, power handling and price point.”
The two way passive Arena 15 boasts powerful low frequency reproduction and a compression driver with a 1.4” voice coil, giving it the flexibility to handle a full range of applications. With a high SPL of 129dB and weighing in at only 23.7kg, it also guarantees easy installation.
“Rotatable horns, M10 rigging points and their lightweight design made them very easy to install from the structure steel,” confirms Baumann. “When it came time to tune the system, we were again amazed at their smooth and articulate response without processing. Final tuning of the system was a breeze. Now that the system is in and has been used for many athletic events and winter commencement ceremonies, it only confirms that our choice in loudspeakers was spot on and consistent with the high level of quality that our reputation is built upon.”
“Soundworks Systems Inc. provided us with an excellent solution for our space,” said Mitch Capelle, Assistant Athletic Director for Media Relations at the University of Wisconsin-Stevens Point. “The space, with its wide variety of uses, needed a system that could provide us with this kind of versatility. Soundworks Systems Inc. perfectly tailored this system to the multiple uses of this showcase facility on our campus to improve the spectator experience, no matter the event in the space.”
Based in Wisconsin, Soundworks Systems Inc. designs and installs audio, video and lighting in a variety of venues including, but not limited to, theatres, houses of worship, indoor and outdoor athletic stadia, schools, boardrooms and local government facilities. In addition, the company provides live production for touring acts and corporate events.
“We have years of experience in the pro audio field, and the dBTechnologies loudspeakers are impressive,” says Baumann, who has since used Arena 8s in a multi media room at the Amherst High School (Amherst, WI), and specified more Arena 15s in a local elementary school gymnasium. “I don’t think the performance of these boxes can be beat at their price point.”
Technomad Upgrades Audio Presence at Club Med Sandpiper
Systems integration firm Axxentos of Fort Lauderdale, Florida turned to Technomad upon evaluating the outdoor audio needs of Club Med Sandpiper in nearby Port St. Lucie. The new outdoor audio systems, featuring 14 Technomad weatherproof loudspeakers, comprise part of a property-wide renovation alongside indoor AV upgrades and general construction projects.
Club Med Sandpiper’s 400-square-mile resort property exists in southern Florida’s sweltering climate, requiring durable outdoor audio systems that can withstand the year-round heat, humidity and moisture. The resort also required high-quality loudspeakers that could power full-range, high-volume audio over long distances, and reproduce soothing background music at clearly audible levels.
“I’ve learned what gear can survive in harsh environments over the years, and from all the outdoor installations I have done, only one company reliably endures the elements — and that is Technomad,” said Olivier De Kegel, owner and president of Axxentos. “They also produce great sounding audio.”
The external pool system proved the biggest challenge as De Kegel had little guidance from the resort, other than that management wanted a nice-sounding background music system during the afternoon and a louder system in the evenings. He installed two Technomad Berlin loudspeakers, the largest loudspeaker in the company’s range, to handle both requests with one system. The Berlins accommodate every activity from Bingo to full-blown nightclub-style events.
Axxentos installed a 70-volt infrastructure to accommodate long cable runs from a new central audio headend to various areas, including the bar. Ten Technomad Vernal 70-volt loudspeakers power the bar zone, delivering music and entertainment to guests enjoying daytime activities and the nightlife.
Two Technomad Noho loudspeakers also welcome guests with high-energy music audio at the entrance as they check in, with lower-volume background music playing in between arrivals.
“The resort wanted a system they could easily manipulate at the welcome area to balance loud and soft audio, and the Nohos offer power that is closer to the Berlin but compact enough for installation at the entrance,” said De Kegel.
Elsewhere, Axxentos installed AV systems in new conference rooms, built a mobile DJ unit and renovated a large theater system, merging existing equipment with some new components. But the outdoor audio systems remain the crown jewel of the resort upgrades.
“This was my largest installation to date, with some interesting upgrades and unique challenges,” said De Kegel. “They went from being fully analog to a more digital, centralized model. There won’t be any dull nights with the high-quality audio systems they have, and the durability of the Technomads ensure they won’t have to replace the outdoor systems every two years.”
Electronic Versus Physical: An Analysis Of Shaping Array Directivity
Electronic modification of an array’s directivity is not always a substitute for good old mechanical arranging or aiming. Here's a look at the differences
Modifying the directivity characteristics of loudspeaker arrays through electronic delay has become increasingly popular.
Whereas 20 years ago the only option was expensive dedicated digital delay units, and a few years later the original BSS Omnidrive was a luxury, the advent of inexpensive digital processing has changed the game.
The design of complex arrays using a relatively high number of processing channels, as required to electronically modify the directionality of an array, is now affordable and widely implemented.
However, virtual (electronic) modification of an array’s directivity is not always a substitute for good old mechanical arranging or aiming, as the two methods have widely differing radiation characteristics off-axis (i.e., to the back and sides).
Let’s look at the differences in the two approaches, how they differ across a number of array types, and suggest applications where each of them should be used with subwoofers.
Arrival Times
The reason why physically moving a loudspeaker backward is different from delaying it electronically may not be intuitively obvious, but is easily shown graphically.
Figure 1a shows two loudspeakers (“A” and “B”) located left and right at equal distance from both a listener positioned in front and another listener positioned behind.
Figure 1: Loudspeakers equidistant to listeners (1a); loudspeaker B moved back (1b); and loudspeaker B electronically delayed (1c).
Leaving aside subtleties such as the location of the time origin of the loudspeakers, since it does not influence the basic concept being discussed here, sound from loudspeakers A and B will arrive at the same time to both listeners.
If we move back loudspeaker B (Figure 1b), then loudspeaker A is closer to the front listener, so sound reaches that listener earlier. Behind the loudspeakers, of course, the opposite occurs.
If we return the loudspeakers back to their original positions, and then apply electronic delay to loudspeaker B (shown in Figure 1c as a diverted path length to the listeners), we see that the output of loudspeaker A arrives earlier than B in both cases (in front and behind).
Thus, it is graphically clear that physically moving enclosure B produces a significantly different result to electronically delaying it.
Focus On The Effect
Let’s now look at the implications within the context of a vertical array of loudspeakers, and predict the coverage of a column of omnidirectional sources.
Figure 2: 3D balloon for mechanically tilted array at 100 Hz (2a); vertical polars for mechanically tilted array at 80, 100, 125 and 160 Hz (2b).
I often prefer to display results via polar plots, because with plane mappings it’s often difficult to understand the behavior at distances other than those close to the system being modeled.
Also note that I’ll use mostly omnidirectional sources instead of “real-world” sources (with a certain degree of attenuation at the back, i.e., not perfectly omnidirectional) to focus on the effect that the arrangement is causing on the directional response of a single loudspeaker.
In Figure 2a and 2b, we have physically tilted a 12-element array that is 23 feet (7 meters) long downward by 30 degrees.
The front part of the radiation points down 30 degrees, and the back part points up 30 degrees, while left and right (i.e., 90 degrees to the sides) are pointing straight, as if the array had not been tilted at all.
Figure 2a shows a three-dimensional directivity balloon resembling some sort of “flying saucer” at an angle, while Figure 2b shows polar plots for the third octave bands between 80 and 160 Hz (the main lobe gets narrower as frequency increases).
In Figure 3a and 3b, the sources are delayed so that the main radiation is (electronically) steered 30 degrees down (by applying increasingly larger delay times from top to bottom).
The balloon looks a bit like a fat cone, showing that the 30-degree downward angle is taking place all around the array, not just in front of it.
Figure 3: 3D balloon for array with delay steering at 100 Hz (3a); vertical polars for array with digital delay steering at 80, 100, 125 and 160 Hz (3b).
This behavior is emphasized by manufacturers of electronically controlled (“digitally steerable”) column loudspeakers, correctly emphasizing that the use of their products yields better coverage than a single, down-tilted conventional enclosure.
Pointing Lobes
To provide another example illustrating the differences between mechanical tilting and delay steering, we modeled one of each in a room, this time using loudspeaker data with realistic nonperfect omnidirectionality.
The resulting pressure maps have been plotted onto the walls as well as the floor, and we’ve also drawn lines, at different horizontal angles, that represent the direction in which the main lobe is pointing.
In Figure 4a (mechanical), the lines follow the shape of a disk, which means that some of the lines are pointing to the walls, and the mapping indeed shows that significant SPL is being radiated towards the walls.
In Figure 4b (electronic), the lines form a cone and sound is mostly focused on the floor.
Figure 4: Room mapping of mechanically tilted array (4a) and an electronically steered array (4b), both at 125 Hz.
The 125 Hz octave band was used for the room predictions; while it is probably somewhat unrealistic of typical subwoofer bandwidth, the narrower coverage is helpful to exaggerate the effect for clarity.
It can also be seen that the covered area is roughly rectangular for the mechanical case and rounder for the electronic one. (Some may recognize the CADP2 graphics. What a beautifully elegant piece of software that was! RIP.)
Exploring Arcs
From the explanation earlier in this article, we can guess that an electronic arc (where input signal is increasingly delayed as one goes from the center to the edges of the array) will display identical front and rear radiation for omnidirectional sources.
A physical arc, in the far field, also provides symmetrical front and rear behavior – but - at close distances, rear levels will be higher.
This is because circular arc sources arrive simultaneously at the circle’s center, i.e. the array’s “virtual origin.” Accordingly, physical arc best practices should avoid any arc that displays an inconvenient center, particularly at center stage.
Figure 5a, 5b and 5c present polars for a physical arc of eight subwoofers spanning 120 degrees with a radius of 10 feet (3 meters).
Figure 5: Horizontal polars for six-element physical arc in the near field (5a); mid field (5b); and far field (5c).
In the near field (Figure 5a), the buildup of sound pressure at the back can be observed, with the array being an average of around 6 dB less sensitive at the front for theoretical omnidirectional sources (though this number changes widely with frequency as seen on the plots).
This translates approximately to the same level back and front for a typical real-life subwoofer (with a certain degree of directionality). Also, in the near field, the rear pattern is narrower at the back.
As we get farther from the array though (Figure 5b), the polars become symmetrical, with the same levels being radiated to the back and front. This was calculated at a distance of 98 feet (30 meters) from the center of the array.
Figure 5c shows the far-field results, made up of equidistant enclosures that would “virtually” follow the same arc as the physical arc above.
Unlike the physical arc, the electronic version shows the same levels back and front both up close and far away from the array.
Figure 6: Side view of stage showing the difference between mechanically aimed arrays (6a) and electronically steered arrays (6b).
In general, an electronic arc is preferred because it does not suffer from pressure build-up behind the array, and it requires less space in front of the stage.
And unlike array steering, where each element requires a different delay time, we can use an even number of elements, so that pairs can share the same delay, meaning one amplifier channel can power two boxes if needed.
Given today’s prices, an extra DSP unit dedicated to subs does not seem too much of a luxury. Mathematically, calculating required delay times for a straight line array of equally spaced boxes may be complicated.
Figure 7: Top view of stage showing the difference between mechanically aimed arrays (7a) and electronically steered arrays (7b).
However, a piece of string can be used to mark a circular arc on the floor as physical reference for measuring “virtual” distances for pairs of subs.
Case Study A: Flown array of subwoofers on an open-air concert. When flying a subwoofer array, if the array is mechanically tilted, the rear radiation lobe will point upward (Figure 6a) and minimize trouble.
Yet it might be tempting to go with a “clean” hang and implement electronic steering, in order to digitally down-aim low-frequency (LF) radiation.
Doing this, however, means that corresponding rear radiation will also be aimed downward, presenting potential noise problems with nearby housing, as shown in Figure 6b.
Case Study B: Opening up left-right subwoofers. Invariably, when left and right subwoofers are used, interference creates the notorious power alley, where LF system response is audibly louder.
Additionally, bass coverage is not uniform since interference patterns change with frequency.
One way to minimize left-right interference is to aim subwoofer arrays away from each other in order to reduce overlap.
If we aim the array physically (Figure 7a), the back radiation lobe will point to the stage, increasing LF spill (again, the extent of this will be reduced through the use of cardioid subs, be it off-the-shelf cardioid models or array elements made up of a cardioid arrangement).
However, if electronic steering is used (Figure 7b), the back lobe will point away from the stage.
Figure 8: 3D view of a flown 360-degree array.
This is actually the same as Case Study A, except for the fact that we are dealing with horizontal, not vertical, coverage.
Case Study C: 360-degree subwoofer array. Certain arena applications might call for 360-degree horizontal subwoofer coverage, as well as some degree of downward firing toward the seating.
Achieving this with mechanical aiming is just plain impossible, but it can be accomplished through the electronic realm.
The suggested design makes use of a somewhat unusual configuration. Since real subwoofers are not entirely omnidirectional (a typical 18-inch subwoofer box may show 4 to 6 dB less at the back relative to the front), to achieve the same level at both back and front, we use a “face-to-face” deployment.
And it might seem a bit counterintuitive, but a physically phase-aligned pair can also be achieved if the correct spacing is used between the two.
To avoid flying too much weight, we could alternate every other element in the array as seen in Figure 8, an arrangement that also minimizes obstructions to the expansion of the wavefront.
Figure 9: Horizontal and vertical polars of 360-degree array at 100 Hz.
This two-column arrangement with electronic steering would generate the directivity balloon seen in Figure 3a (except that the sides would be slightly squashed), with the horizontal and vertical polars that can be seen in Figure 9.
As with any low-frequency array, a longer array generates a narrower radiation pattern, which means that different venues would require different lengths to suit their geometry.
From the point of view of level consistency, the arrangement in Figure 8, with real non-perfectly omnidirectional sources, would send slightly less SPL to the sides (in our case, around 3 dB less for a real single 18-inch front-loaded subwoofer), which would be desirable on a rectangular arena to compensate for the difference in distance to the closest and farthest tiers.
On the other hand, given the uniform downward profile, this configuration would be ideally suited, angle-wise, for circular venues such as a bullfighting ring or a Mexican Palenque.
Watch That Space
As we know from line array “laws” there is a maximum spacing between sources for any given frequency.
Figure 10: 3D balloon for 6 element array with delay steering at 160 Hz (10a); Vertical polars for a six- element array with delay steering (10b) and with mechanical aiming (10c) at 80, 100, 125, 160, 150 and 250 Hz.
If that spacing is exceeded, the array loses the ability to control directivity, with higher frequencies showing lobes at the wrong angles and eventually losing directivity control. This is even more so for an electronically steered array, which requires a tighter element density.
Figure 10a shows a three-dimensional representation of the directivity balloon of an electronically steered array with excessive spacing (4.5 feet).
A significant top lobe can be seen that will surely create reverberation issues at that frequency in an indoor venue.
Figure 10b presents 80 to 250 Hz one-third octave polars for the same array where the three highest frequencies have gone haywire across the top part of the curve.
In contrast, a mechanically tilted array of subs (Figure 10c) with the same spacing only shows misbehavior at 250 Hz, which corresponds to a wavelength that correlates roughly to the spacing between sources, so it’s no surprise.
José (Joe) Brusi is an independent electroacoustical consultant. And thanks to Joan La Roda for the field phase measurements of the alternate face-to-face subwoofer configuration.
Peavey Announces New PVX Series Active & Passive Loudspeakers
At the NAMM 2012 Show, Peavey Electronics introduced the new PVX Series of active and passive loudspeakers.
The compact, portable PVXp 12 and PVXp 15 active (powered) models incorporate 800 watts of peak power, combined with proprietary DDT compression technology to maintain clarity throughout the mix. A module bay allows for use of expansion modules to increase the functionality of the enclosures.
The PVX 12 and PVX 15 passive (non-powered) loudspeakers are specified as being capable of handling 400 watts program and 800 watts peak power, respectively.
Peavey PVX enclosures are constructed with heavy-duty Peavey woofers with 2-3/8-inch voice coils for the lows and low-mids, while the Peavey RX14 1.4-inch titanium diaphragm compression driver, coupled to a constant directivity horn, handles the highs and mid-highs.
All have injection-molded enclosures that include a pole mount, three multi-point flying locations and a tilt-back design to accommodate use as a personal monitor. A black powder-coated steel grille provides driver protection and a clean, professional appearance.
The Peavey PVX Series passive enclosures will be available in Q1 2012, and the PVXp active enclosures will be available in Q3 2012.
Features: —Two-way 800 watt peak power (active versions) —DDT compression and protection (active versions) —RX 14 titanium compression driver —12-in or 15-in Peavey woofer with 2.3-in voice coil —Multiple cabinet fly points —Pole mountable cabinet —Molded in cabinet handles —Expansion module bay —Angled side for use as monitor when required —LED signal present and DDT active indicator —Rugged polypropylene molded enclosure —Combination 1/4-in and XLR input —XLR and 1/4-in through outputs —44 pounds for PVXp 12; 47 poundsfor PVXp 15 —U.S. MSRP $499.99 (PVXp 12); $549.99 (PVXp 15); U.S. MSRP $299.99 (PVX 12); $399.99 (PVX 15)
Alto Professional Unveils TRUESONIC Wireless, Powered Loudspeakers
At the NAMM 2012 Show, Alto Professional unveiled two new powered, wireless loudspeakers, the TRUESONIC Wireless TS112W and TS115W.
Both models provide clean, transparent sound from wired or wireless sources. .
The TS112W and TS115W are two-way, 12-inch and 15-inch models, respectively. They are outfitted with 800 watts of Class D power and are specified to provide SPL of 125 dB for the TS112W and 126 dB for the TS115W.
The TRUESONIC Wireless line simplifies the connection to multiple devices with the ability to play audio from any Bluetooth audio-equipped device such as an iPad, iPod touch, iPhone or other smart phone.
In addition, both TS112W and TS115W include two Mic/Line Female XLR - 1/4-inch combo inputs with independent gain controls so it’s easy to get up and running with just about any audio source.
“TRUESONIC speakers are already established as the most powerful in their class,” said Jay Schlabs, executive director of Alto Professional. “With wireless capability, the TRUESONIC series is now one of the most versatile speaker lines on the planet.”
The TRUESONIC TS112W and TS115W are expected to arrive at pro audio and live sound retailers in Q2-2012 with an MSRP of $549 (TS115W) and $499 (TS112W) and estimated street prices of $449 (TS115W) and $399 (TS112W).
Shedding some light on the sensitivity specification and how it may translate to the real world performance of a loudspeaker system
The specification of a loudspeaker’s sensitivity is probably one of the most common, yet perhaps one of the most misunderstood.
It’s common to see the magnitude response of a loudspeaker system reduced to a single number as a sensitivity rating.
This is perhaps at the heart of the confusion.
One would think that this metric should give some indication as to how loud a particular loudspeaker will be when reproducing a signal.
One may also think that two loudspeakers with the same sensitivity rating will be equally loud when reproducing the same signal. Each of these assertions is only partially true.
A loudspeaker’s sensitivity can give an indication of its output level but only for a signal with a specific bandwidth and spectral content.
Similarly, two loudspeakers with the same sensitivity may not output the same SPL when excited by the same signal if the frequency response limits of the two loudspeakers are different. Let’s look at the underlying cause of each of these effects, bandwidth, and the role it plays, and also look at why sensitivity may no longer need to be referenced to a watt.
According to the standard IEC60268-5, a loudspeaker’s sensitivity is determined by measuring its output when driven by a band limited pink noise signal with a Vrms equal to the square root of the loudspeaker’s rated impedance and referencing this SPL to a distance of 1 meter.
The bandwidth of the pink noise is limited as a function of the effective frequency range of the DUT (Device Under Test). This is done to ensure that the test signal is confined to a portion of the frequency spectrum in which the DUT has appreciable output.
If a particular loudspeaker isn’t capable of reproducing signals below 150 Hz it does no good to excite it with such signals other than to generate heat. The same holds true if the loudspeaker can’t reproduce signals above some high frequency limit.
A high-resolution transfer function measurement of the DUT can also produce an identical sensitivity rating when the average magnitude is calculated on a log frequency basis.
As an example, let’s look at Figure 1. Here we see the on-axis response of a loudspeaker. Its sensitivity rating is shown as the straight line.
Figure 1: Magnitude response and single number sensitivity rating of loudspeaker system A. (click to enlarge)
The length of this line coincides with the upper and lower frequency limits of the pink noise used to measure the sensitivity rating.
The spectral content of this noise signal is shown in Figure 2.
Figure 2: Spectral content of signal used to determine the sensitivity rating of loudspeaker A from Figure 1. (click to enlarge)
If a signal with different spectral content, but the same broadband level were used to drive this loudspeaker, would it result in the same SPL as the sensitivity?
It’s impossible to determine this without knowing both the spectral content of the signal and the response of the loudspeaker. (Note that 20 Hz to 20 kHz, or in the case of Figure 1, 110 Hz-8.3 kHz, does not specify the response of a loudspeaker. A graph of the response curve really needs to be known.)
With knowledge of these, we can certainly make an estimate to answer this question.
The spectral content of three different signals is shown in Figure 3.
Figure 3: Spectral content of signal used to determine the sensitivity rating of loudspeaker A in Figure 1 (red), speech (grey), and speech-shaped noise with approximately the same spectral content as the speech (blue). (click to enlarge)
One is the band- limited pink noise signal used to determine the sensitivity of the loudspeaker. The others are speech and a shaped noise signal having approximately the same spectral content as the speech. This speech-shaped noise is used instead of speech as its RMS level is more consistent as a function of time than actual speech.
Thus, it will be easier to determine the SPL output by the DUT with this signal. All three signals have approximately the same broadband RMS level. From approximately 200-800 Hz the speech-shaped noise signal has greater level than the pink noise signal.
Above and below this frequency region the pink noise signal has much greater level than the speech-shaped noise signal.
Comparing this to the response of the loudspeaker in Figure 1 we see that the loudspeaker has limited output below 150 Hz. The greatest output in the response of the loudspeaker occurs in the 300 Hz-3 kHz region.
If the speech-shaped noise signal were used to drive the loudspeaker with the same broadband level as the noise we could reasonably expect the broadband SPL to be greater than when driven with the pink noise signal.
This is exactly what happens.
The sensitivity of the loudspeaker is 97.1 dB. When driven with the speech-shaped noise the SPL is 98.1 dB, an increase of 1.0 dB.
This results from the higher level of the speech-shaped signal in the frequency region where the loudspeaker has higher output capability compared to the rest of its pass band.
Conversely, if the low-frequency band-limited pink noise shown in Figure 4 were used to drive the loudspeaker it is reasonable to expect that the SPL would be less than when driven by the noise signal.
This results from the low-frequency pink noise signal having a higher level in the frequency region where the loudspeaker has lower output capability.
The SPL produced by the low-frequency pink noise is 94.9 dB, a decrease of 2.2 dB.
Figure 4: Spectral content of signal used to determine the sensitivity rating of loudspeaker A in Figure 1 (red) and of low frequency band limited pink noise (green). (click to enlarge)
Now let’s compare two different loudspeakers. Figure 5 shows loudspeaker A compared to loudspeaker B. Notice that they both have the same sensitivity, 97.1 dB.
Loudspeaker B, however, has greater low frequency and high frequency extension than loudspeaker A.
Figure 5: Magnitude response and single number sensitivity rating of loudspeaker system A (red) and loudspeaker B (black). (click to enlarge)
Because of this the bandwidth of the pink noise used to determine the sensitivity of loudspeaker B is greater than the bandwidth of the noise used for loudspeaker A (Figure 6).
As a result, the mid-band level of the noise for loudspeaker B is slightly less than that of the noise used for loudspeaker A. It’s a bit difficult to see but upon careful observation the black trace can be seen to be an average of 0.5 dB below the red trace from approximately 100 Hz-10 kHz.
Figure 6: Spectral content of signal used to determine the sensitivity rating of loudspeaker A (red), loudspeaker B (black), and broadband pink noise (green). (click to enlarge)
This is due to the greater bandwidth of the signal used for loudspeaker B (black trace). Remember that the broadband levels of both these signals are identical.
So what happens when each of these loudspeakers is driven by the broadband pink noise signal (20 Hz-20 kHz) also shown in Figure 6? As each of the loudspeakers used in this example are markedly not flat in their mid-band response there may be some tonal, and potentially measurably, differences in the SPL.
Hopefully, the reader can put these issues aside for the moment. All other things being equal, the loudspeaker with the greater effective frequency range (low- and high-frequency extension) should have greater SPL output.
Loudspeaker B should have slightly greater output when driven by this broadband pink noise signal. In fact, loudspeaker B measured 0.8 dB greater than loudspeaker A, 97.0 dB compared to 96.2 dB.
From these examples one should be able to see that the SPL generated by a loudspeaker is a function of both the loudspeaker’s transfer function and the spectrum of the signal being reproduced.
Several acoustical room modeling programs take this into account when calculating the SPL produced over an intended audience area. They may allow for the selection of pink noise, some sort of speech spectrum, or a user-defined spectrum.
This should aid the sound system designer, while still at the drawing board stage, to better understand the potential SPL capabilities of the sound system with the typical program material the system is likely to be reproducing.
The other item I mentioned at the beginning of this article was referencing sensitivity measurements to one watt being dissipated by the DUT. There are several reasons why I think that this is not beneficial with modern sound systems.
First, it is somewhat cumbersome to determine how much voltage is required across a particular DUT such that the input current drawn from the driving source yields 1 watt. This can be done using dual channel FFT measurement systems and an appropriate current monitor or probe.
But would this give us useful information for the design and/or specification of loudspeakers or sound systems?
We can simplify this measurement procedure so that we don’t concern ourselves with the dissipation of a real watt by the DUT.
Instead we apply a voltage across the DUT that would dissipate one watt in a pure resistance having the value of the rated impedance of the DUT.
This certainly is easier, but again, does this give us useful information for the design and/or specification of loudspeakers or sound systems? Perhaps.
My thought is that more useful comparative information would be gained by applying the same voltage across the DUT regardless of its impedance.
The majority of amplifiers used in sound systems today are of a constant voltage type. That is to say, their output voltage remains constant independent of the load placed on them. Of course, the load must be within the specified operational limits for a given amplifier.
The salient point is that for a given drive voltage, a lower impedance loudspeaker will have greater SPL output than a higher impedance loudspeaker; all other items being equal.
Shouldn’t this be reflected in the sensitivity specification of the loudspeaker? Why then would one want to use a 2.0 Vrms signal to drive a 4-ohm loudspeaker and a 2.83 Vrms signal to drive an 8-ohm loudspeaker to determine their respective sensitivities?
Think about it this way; let’s connect two virtually identical loudspeakers to an A/B selector switch driven by the same amplifier.
The only difference between these loudspeakers is that one is half the impedance (rated at 4 ohms) than the other (rated at 8 ohms).
When switching between these two loudspeakers the output voltage of the amplifier does not change, however, the current drawn from the amplifier does.
This results in the loudspeaker with the lower rated impedance producing greater SPL.
Measuring and specifying sensitivity with the same voltage, regardless of the impedance of the DUT, would accurately reveal the SPL differences that occur.
From these examples, I hope that it’s clear that the input signal and the magnitude (frequency) response of a loudspeaker will determine the SPL generated, not just the sensitivity rating of the loudspeaker.
It’s much better to have knowledge of the loudspeaker’s response in the form of a graph than a single sensitivity number. The latter may be derived from the former.
Charlie Hughes has worked at Peavey Electronics and Altec Lansing. He currently heads up Excelsior Audio Design & Services; a consultation, design and measurement services company based near Charlotte, NC. Charlie is a member of the AES, ASA, CEA and NSCA. He is an active member of several AES and CEA standards committees.
Grant, who will be based at the company’s headquarters, will apply his experience in tour and production management as well as front of house and monitor systems/mixing to the technical sales and support departments.
Working directly with such acts as Hawksley Workman, Great Big Sea, Our Lady Peace, and Sloan, as well as hire companies Sound Plus Show Systems and Towers Productions (Now part of Clair Global), Grant has more than 10 years of experience on the road, and is an honors graduate of the Harris Institute for the Arts.
Director of marketing and sales Jesse Adamson states, ” The response to Project Energia in Phase One has been met with enthusiasm on all fronts and we are preparing for the unveiling of Phase Two. We selected Ryan to help support the building momentum with Energia after careful consideration. He brings a broad range of experience from of our industry and this is a great fit for our firm.”
Grand adds, “I have long requested Adamson products on my technical rider and I’m looking forward to being a part of this very energetic and passionate team. The new generation of technology that we are about to unveil offers touring solutions that are second to none.”
Quote meon an estimate et non interruptus stadium. Sic tempus fugit esperanto hiccup estrogen. Glorious baklava ex librus hup hey ad infinitum. Non sequitur condominium facile et geranium incognito.
