Thursday, October 18, 2012
Adamson SpekTrix Arrays, Subwoofers Highlight New System At South Korea’s New Haneulyeon Theatre
Left-center-right configuration with arrays flown, plus additional subwoofers and delay boxes
Dureraum, a newly constructed architectural wonder in Centum City of the Haeundae District in South Korea, is a three-building facility highlighted by the Haneulyeon Theatre (“Open Sky Theatre”), an 841-seat multipurpose performing arts hall with a main sound reinforcement system headed by Adamson Systems SpekTrix line arrays.
The system design and installation was handled by Kang-dong Media of Busan, with support provided by Adamson Korean distributor Sound Solution and Sohn Gun Ho, director Kang-dong Media. In addition, Adamson applications engineer Ewan McDonald was onsite to head up the system tuning process. Byung Tae Kim serves as the theatre’s full-time front of house engineer.
Specifically, the main system offers a left-center-right configuration, with left and right flown arrays each comprised of nine SpekTrix 3-way enclosures hung below four SpekTrix double 18-inch subwoofers, with three SpekTrix W 15-degree boxes under hung.
The location of these arrays was changed from the original design to about a meter wider on each side due to an issue caused by reflection of the bass from the acoustic treatment used in the interior ceiling. The slight adjustment in positioning of the main hangs resolved the problem in the initial design.
The center cluster, meanwhile, incorporates seven SpekTrix modules, with two more SpekTrix W under hung. Four Adamson SX subs are also located on the ground, and can be moved for optimal placement for the needs of each performance.
A dozen Adamson Point 8 loudspeakers on digital delay provide fill to the theatre’s balconies, while four Adamson M15 monitors are available for use on the stage.
The loudspeakers are driven by Lab.gruppen power amplifiers, including models FP10000Q, FP6000Q, and FP4000. Digital processing is supplied by XTA DP Series processors. The house mixing console in the theater is a DiGiCo SD7.
“The team at Sound Solution did a very professional job with this installation in what is a world class facility,” McGregor states. “After some time was spent commissioning, we ended up with a very nice sounding system, with no more than +/-0.5 dB variation (A weighted SPL) throughout the floor and the mid balcony, which was a testament to the great work the design team at Sound Solution does.”
Dureraum, also known as the Busan Film Center, hosts the renowned Pusan International Film Festival (PIFF), and isalso used as the venue for both opening and closing ceremonies. The facility was designed by Coop Himmelblau of Austria and Heerim Architects & Planners of Korea, both whom were selected in an open competition.
Dureraum is composed of three separate spaces—Cinema Mountain (home of the Haneulyeon Theatre), PIFF Hill and Double Cone. The building varies from four to nine stories high with a combined total floor space of 54,335 square meters. The essence of Dureraum’s beauty is its super-sized roof known simply as the “Big Roof”—the longest roof of its kind in the world, about one and a half times the size of a soccer field (163m × 61m or 535 ft x 200 ft).
More Than 560 QSC AcousticDesign Loudspeakers Reinforce Atlantic City’s New Revel Casino-Resor
Deliver consistent coverage and quality audio to gaming floor
Montreal-based Scéno Plus, noted for its theatre design work in Las Vegas, Canada, and other locales, recently completed a major, multi-venue project at Revel, the new $2.4 billion casino-resort at the north end of Atlantic City’s famed boardwalk.
Scéno Plus was the lead designer for all of the entertainment spaces at the Revel, including the Revelry casino floor, where the company designed, specified and optimized nearly 570 QSC Audio AcousticDesign Series ceiling- and surface-mount loudspeakers.
Scéno Plus was responsible for the design of two large, multipurpose, transformable venues, several bars and various interconnecting spaces at Revel. The resort, which fronts onto the beach, covers 20 acres and, at 47 stories, is the tallest building in Atlantic City.
In a break with traditional casino design, Revelry’s 130,000-square-foot gaming floor includes windows offering panoramic views of the Atlantic Ocean. As daylight fades, audiovisual, lighting and interior design elements dynamically change the ambiance of what are referred to as “neighborhoods” on the floor as the night’s entertainment begins.
“The client wanted to have a high-end theatrical experience on the gaming floor,” explains Simon Léonard, AV Designer, Scéno Plus.
The constant-voltage distributed audio system on the Revelry casino floor includes 274 QSC AcousticDesign AD-CI52ST ceiling speakers, which employ 5.25-inch LF transducer, a 1-inch titanium dome tweeter and a ported enclosure for greater low frequency extension. as well as170 QSC AcousticDesign AD-S52T two-way surface-mount speakers, also incorporating a 5.25-inch woofer and 1-inch neodymium tweeter and 125 QSC AcousticDesign AD-C81Tw ceiling-mount 8-inch subwoofers.
“The AcousticDesign line was a great choice, because the client really wanted to have fullness and richness of both the high-end and the low-end,” says Léonard. “So we needed a product that could suit that large, broad spectrum, and would also be really comfortable to listen to.”
Despite the significant differences in ceiling height and of finish materials between one neighborhood and the next, the QSC AcousticDesign products were remarkably easy to dial in, according to Léonard.
“The voicing of the whole line is very nice,” he says. “You go from a low ceiling area to an open part of the casino, where AVI/SPL & CALVI worked hard to maintain a certain level of consistency in the trim heights, but the voicing is really similar. You could also get more of the same response between the ceiling and the surface mount versions, which is very nice.
“We were really astonished at how we could easily, without EQ’ing for hours, get the same response everywhere. We were also surprised to hear how the AD speakers sounded right out of the box, off-, as well as, on-axis. You can really get something that is consistent throughout the whole coverage area.”
The loudspeakers serving on the casino floor also needed to be of high quality, capable of acting as an extension of the sound systems in several of the featured spaces. These include The Social, a two-story, high-energy show-bar in the center of the gaming floor that hosts a variety of events, including musical guests; the Digipit, an area with a raised runway, two raised stages and space for acrobatic and aerial performances; and the Immersive Dome, an overhead, 360-degree digital video projection installation.
“There are a couple of features like that on the Revelry floor that the system can take its source from,” says Léonard. “So we put a lot of attention into how we were going to zone the system, just to make sure that we would be able to maintain something that makes sense with the architecture.”
The changing environments and various show elements are pre-programmed and played out through show control automation. “So the floor manager at any time can override the timeline and select something at the catwalk, or later if there’s something happening in the bar and they want to extend the experience onto the floor, they are always able to do so. That’s why we had to provide a sound reinforcement system that would reflect or extend the quality of a live event. It’s more or less an extension of a concert system,” he elaborates.
Scéno Plus collaborated on the Revel project with Claude Ricard and Marc St-Jacques of SF Marketing, the QSC distributor for Canada. “We had the opportunity to do a mock up in their facility, so we could really compare what EASE Address was saying to compare it with the real life installation, or as close as we could get it. Those guys were really a big help,” says Léonard. We were really happy about how it turned out.” More importantly, he comments, “The client is really pleased with the results.”
About QSC Audio
QSC Audio Products, LLC is a leading manufacturer of power amplifiers, loudspeakers, digital signal processors, digital sound transport, and network audio for professional audio systems worldwide. qsc.com
Dean College Upgrades To A Pair Of Allen & Heath iLive Digital Mixing Systems
Two facilities benefit from technology update at college
Founded in 1865, Dean College in Franklin, MA offers a variety of arts and entertainment management majors, and has several live performance spaces—some of which double as classrooms.
In 2010, the college expanded the Campus Center, with a new “Main Stage and Dining Wing” housing a multi-use theater equipped with a versatile sound system, including an Allen & Heath iLive digital mixing system. A second iLive system is installed in the Dean College Guidrey Center.
“We host a wide range of live drama, musical and dance performances,” says Mike Sartini, chief audio technician at Dean College. “I was mostly familiar with analog mixers but I knew we needed a digital mixer for the Main Stage and the Guidrey Center. They had to be powerful enough to handle our modern productions but also they had to be simple to operate when the theaters are used as classrooms.
“I talked to my friends who do Broadway shows and we looked at several digital mixers but, after seeing a demo at Wavelengths Pro Audio, we chose the iLive.”
Alan Redstone of Wavelengths (based in Leominster, MA), who sold and installed the two iLive systems, explains, “For the Main Stage theater Dean College chose the larger 112 Surface and iDR10 MixRack. That gave them plenty of inputs for their larger productions and the larger Surface to see a whole show at once. For the classes in the Main Stage, we installed a PL10 remote control near the stage. They can select a ‘scene’ at the PL10, plug in local sources and operate the system without touching the 112 surface.
“For the Guidrey Center, we installed a smaller iLive T80 Surface and iDR32 MixRack. And, like the Main Stage, they’ve got a PL10 in the Guidrey Center for classes and presentations.”
Sartini uses the iLive’s iPAD app to walk the theater and make changes during a performance. “Our control room has a window that opens but it’s still hard to hear everything accurately so the iPAD app really helps,” he says, adding, “some digital mixers sound brittle to my ear but the iLive sounds great. I love the EQ and the compression is excellent.”
Main Stage productions are often mixed by an outside engineer. Sartini notes that “even when they have no digital experience, I can get them up and running on the iLive quickly. If they need lots of monitoring, we’ve got that covered as well and I can even send an Aviom monitor mix.”
For future expansion, Sartini says the college plans to implement the iLive’s Dante interface to interconnect the Main Stage and Guidrey Center. This will also allow them to send live sound over the campus network to remote classrooms and to the college radio station for broadcast and recording.
Allen & Heath
American Music & Sound
Wavelengths Pro Audio
Lectrosonics Digital Hybrid Wireless Chosen To Upgrade Audio Quality At Finland Theatre
A total of 22 channels of wireless for a variety of productions
Designed by Alvar Aalto and built in 1982, the Jyväskylä City Theatre, in Jyväskylä, Finland, is the largest venue of its type in this city of roughly 132,000 people, and as such, it is home to a broad assortment of cultural activities, including concerts, musical theatre, and opera.
The venue recently sought to upgrade its audio presentation, choosing to do so with Lectrosonics wireless microphone systems incorporating the company’s Digital Hybrid Wireless technology. Noretron Broadcast Ltd of Kirkkonummi, Finland, handled the sales and installation of the theatre’s new wireless system, a process headed by company owner Timo Vilmi.
“The Jyväskylä City Theatre has two rooms, with the main stage having seating for 551 people and the secondary room being far more intimate in character—with seating for 98 people,” Vilmi explains. “As the premiere facility of its kind in this region, we wanted to ensure the best possible audio quality and the highest level of reliability. Mika Filpus, the theatre’s chief sound engineer, evaluated several brands and, based upon his findings, ultimately selected Lectrosonics.”
Specifically, the Noretron Broadcast team deployed 22 Lectrosonics SMDB/E01 super miniature beltpack transmitters and two HH/E01 handheld transmitters. On the receiver side of the equation, there are four Lectrosonics WRMWB Venue Series/E01 receiver mainframes—with all but one of the 6-channel systems fully stocked with VRT receiver modules for a total of 22 channels.
Lectrosonics ALP650 skeletal design Log Periodic Dipole Array antennas augment the system, as do RM remotes, which enable audio technicians to modify audio input gain, RF operating frequency, lock/unlock the front panel controls, and enable/disable Sleep Mode on the SMDB/E01 transmitters.
“Audio quality was the first and foremost concern,” states Vilmi, “and this is precisely why the Lectrosonics gear was chosen. Lectrosonics’ Digital Hybrid Wireless technology sounds exceptional and exhibits none of the sonic artifacts one typically encounters with systems using a compandor. The SMDB/E01 transmitters are extremely small and, as a result, are easy to hide among wardrobe, so they’re a great choice for theatrical applications—and with the RM remote, an audio tech can make changes to the transmitter without interfering with the talent’s wardrobe. Combine these factors with first-rate build quality and it’s easy to see why Lectrosonics excels in this type of environment.”
The first event to avail itself of the new Lectrosonics wireless microphone system was the Finnish musical Myrskyluodon Maija. “The show opened September 9th and was very well received,” Vilmi states. “The combination of the Lectrosonics wireless equipment with the DPA 4061 lavaliere and d:fine earset mics makes a terrific setup.”
Harman Professional Hosts Installed System Applications Seminar In Sao Paulo, Brazil
Served to introduce Harman product and technology specialists and system design expert Vance Breshears of Acoustic Dimensions
Harman Professional recently hosted a three-day seminar on installed system applications in Sao Paulo, Brazil with an international team of presenters.
The event was planned in collaboration with Harman’s Brazil country head Rodrigo Kniest and Fernando Guerra, sales manager for installed sound & cinema. It served to introduce Harman product and technology specialists and invited guest speaker and sound system design expert Vance Breshears of Acoustic Dimensions, along with Harman Brazil’s new pro sales & marketing director, Sergio Luis Smidt, to the audio design and installation community in Brazil.
According to David Scheirman, director, knowledge resources for Harman Pro, the seminar is part of a growing information platform being developed to engage and update system designers, specifying engineers and AV consultants worldwide.
The timing and choice of location were set to leverage the considerable interest about Harman products from audio and systems integration professionals in the Brazilian market.
“Since recently making Brazil’s Selenium Electronica an important part of Harman Professional’s global business development and growth strategy, we have become much more deeply engaged with audio professionals in this region. That has led to a strong dialog and exchange of ideas,” Scheirman states. “Cross pollinating geographic regions with ideas and techniques is always exciting and consistently yields value for everyone involved.”
The Sao Paulo program covered the fundamentals of sound and communications systems design from specification to commissioning. Additionally, it provided deep insights into complex system applications including sports stadia, live performance venues, hospitality venues such as hotels, bars and dance clubs and communication and paging applications ranging from typical conference and boardroom spaces to large-scale transportation facilities.
The seminar featured the latest technologies from AKG, BSS, Crown, dbx, JBL and Soundcraft Studer. Attendees also gained an experiential audio-visual exposure to IDX, Harman’s new unified paging and message delivery platform. Simultaneous translation in both the English and Portuguese languages was available for all attendees.
“With a robust economy, and with numerous fixed-venue design and installation opportunities resulting from Brazil’s upcoming global-scale sports and entertainment events on the calendar in the next few years, we are investing in more of the necessary personnel and resources to provide our customers with the knowledge and support they require to be successful in these areas,” says Kniest. “Having first-hand access to world-class experts and leading-edge tools gives our customers a competitive edge in this growing market for sound and communications systems.”
Range Of WorxAudio Loudspeakers Fill Multiple Needs At North Carolina Church
Broad horizontal dispersion and low profile design characterizes new setup
An A/V upgrade for the sanctuary at the First Baptist Church of Lenoir (North Carolina) to handle a wider range of worship service styles includes a range of WorxAudio Technologies loudspeakers, chosen by the design/build firm that headed the project, Selah Media Productions of Boone, NC.
Specifically, the system designed by Selah Media Productions president Buck Roberts includes a six-element X1i-Passive line array suspended via a WorxAudio TrueAim Grid, augmented by a V5M-P line array element, two WaveSeries 8M stage monitors, and a pair of I/O-4 surface mount loudspeakers.
“Church management wanted their new sound system to be able to handle as wide range of events as possible so as to be well positioned for the future,” Roberts explains. “The previous sound system consisted of several portable PA loudspeakers that church volunteers had mounted on the side walls of the sanctuary. The system exhibited a number of issues that really hampered its effectiveness, so it was important for the new system to correct this situation.
“Room aesthetics were an equally important consideration and, as a result, the system was to have a low profile. This led us to a centrally positioned loudspeaker cluster—painted white so as to blend in with the rest of the sanctuary.”
The X1i-PAS is a compact, 2-way, high-efficiency, line array loudspeaker offering a broad 160-degree horizontal dispersion pattern, which works well in the sanctuary’s roughly 60 by 60 foot space.
The TrueAim Grid mounting system uses a single schedule 40 pipe for the loudspeaker array’s suspension and employs a unique coupler that connects to the grid’s adjustable crossbeam to facilitate both left and right adjustment.
Further, the pipe coupler has an exit point through which the array’s wiring can pass. By running the wire through the pipe and exiting via the coupler, the line array’s audio and power lines are hidden from view and visible only at the back of the system—creating a clean, uncluttered appearance free from the distractions of visible cable.
“The church has a plaster ceiling.” notes Roberts. “As a mounting system, the TrueAim Grid is as minimally invasive as possible, and this enabled us to preserve the character of the ceiling.”
Mounted onto the rear of the TrueAim Grid is a single WorxAudio V5M-P. This powered 2-way line array loudspeaker is angled down toward the stage area and serves as the monitor for the choir. It is entirely hidden from the congregation’s view.
Two WorxAudio PXD-8080 (800 watt by 800 watt) power amplifiers are used to drive the X1i-PAS line array system. These amplifiers are also mounted to the rear of the TrueAim Grid.
As the sanctuary includes a balcony at the rear of the space, Roberts elected to place two WorxAudio I/O-4 surface mount loudspeakers as under-balcony fills. These injection molded, high-impact polycarbonate enclosures are on a slight delay so as to seamlessly blend with the sound emanating from the front stage / altar area.
“The X1i-PAS has great throw,” says Roberts, “but I wanted the final 2-3 rows under the balcony to have the same coverage as the rest of the room, and these loudspeakers were just the ticket.” Two WorxAudio WaveSeries 8M two-way, high efficiency, passive stage monitors complete the sound system. These monitor are deployed as necessary—depending upon the nature of the service.
First Baptist Church’s new sound reinforcement system was installed during July and August and was immediately placed into service thereafter. With roughly a month of service, Roberts reports everyone is very pleased.
“The new system is working out really well,” says Roberts. “Both the congregation and church management have been very complimentary of the new system. The entire WorxAudio team was extremely supportive of this effort. They not only made product recommendations, the provided EASE data as well. When I have an installation project, WorxAudio is the first company I think of.”
Paul McCurry, Director of Multimedia at First Baptist Church, echoed Robert’s enthusiasm, “Our church recently underwent an upgrade to the A/V system in the Sanctuary. This process was not done without careful study on what would be going into a 1925 built room full of beauty and history, but not built for amplified sound.
“The end result was a system that has garnered nothing but positive comments from both the technical crew and, far more importantly, the congregation. We feel this was made possible by the careful design and implementation of the speaker system. Clearly a tribute to the speakers used, and the company that installed them.”
Selah Media Productions
Wednesday, October 17, 2012
New v4.7 For Soundcraft Vi Consoles Provides 96 Channels To Mix For Vi4 And Virtual Vi For Vi1
With 96 inputs, the Vi4 is in line with Vi2 and Vi6 models, with show files also compatible across all models
The new V4.7 release of software for the Soundcraft Vi Series range of digital consoles brings a major input capacity increase for the Vi4 model, as well as new Virtual Vi software for the Vi1 and a number of feature upgrades across the board.
The Vi4 can now handle 96 inputs to mix, bringing it into line with the Vi2 and Vi6 models, and show-files are now fully compatible between Vi2, 4 and 6 consoles, so settings can be quickly and easily moved between consoles from a USB memory stick.
To take advantage of the 96 inputs to mix on the Vi4, 3 DSP cards must be fitted to the local rack, so exiting Vi4 owners can upgrade very easily. Vi4 consoles with only two DSP cards will be uplifted to 64 inputs to mix, from 48. Similarly, rental companies with inventories of both Vi4 and Vi6 can now standardize on local racks.
The same software update brings the dedicated Virtual Vi offline editor for the Vi1 console so users can take full advantage of the Vi1 functionality to program shows offline.
Other software enhancements in V4.7 include EQ width control options in Q or octaves delay unit settings in milliseconds, metres or feet & inches, and a number of other user interface enhancements.
The new software can be downloaded here.
Outline And Production Resource Group (PRG) Announce Strategic Partnership
PRG Las Vegas Will Serve as central hub for Outline U.S. initiative
Outline S.r.l. and U.S. subsidiary Outline North America, LLC have entered into an agreement with Production Resource Group (PRG), one of the largest production services companies in North America.
Specifically, PRG’s Las Vegas facility, the hub of the company’s touring sound business, will inventory and stage Outline GTO, GTO-SUBS, Butterfly, MANTAS, DBS18-2 Subs, and LipFill-0182 loudspeakers.
PRG handles all aspects of live event presentations including lighting, video effects, scenery and sound for Broadway productions including Spiderman: Turn Off the Dark, and major live television presentations that include the Academy Awards. PRG also provides extensive audio systems, stage design and lighting effect systems for major tours and events such as Elton John, Black Eyed Peas, Red Hot Chili Peppers and the Super Bowl halftime show.
A joint launch of the GTO and Outline partnership is planned to coincide with the upcoming LDI Show and Parnelli Awards in Las Vegas. A Stageline Mobile Stage, with an Outline GTO rig, will be set up on the grounds of the PRG complex. Transportation to and from the PRG compound from the Las Vegas Convention Center will be provided as a courtesy to invitees, and those wishing to experience GTO.
“Timing could not be better to announce this relationship,” says Tim Brennan, PRG vice president. “Many of our clients, production managers and contemporaries with whom we have a professional trading relationship will be in town for LDI. This is the perfect opportunity for us to introduce them to the quality and unique engineering expertise of Outline and its GTO.”
“We are very excited to enter into this relationship with PRG,” says Giorgio Biffi, CEO of Outline S.r.l. “This comes at a very exciting time for our company, as we continue our global growth initiative with the addition of many of the world’s largest premier sound and production companies. PRG is a wonderful and welcomed addition to our family of Outline partners.”
PRG joins GABISOM, the largest production company in South America, as an Outline partner.
“I have seen the incredible growth of PRG over the years and am very pleased to have them help lead the charge for our large format line array, the GTO, in the U.S.,” says Tom Bensen, Outline North America senior vice president - partner and managing director.“We appreciate PRG’s confidence in our company and their shared vision for the future as we begin this relationship.”
Dual Yamaha DM2000 Consoles Utilized For Hofstra Presidential Debate
Chosen specifically to provide two separate audio streams
The second presidential debate (held October 16, 2012) between President Barack Obama and former Massachusetts Governor Mitt Romney at Hofstra University on Long Island (NY) had audio production provided by On Stage Audio (OSA), based in Las Vegas.
The site of the debate, which was done in a “town hall” format, The David S. Mack Sports and Exhibition Complex on the campus of Hofstra served as the site of the debate, which was done in a “town hall” format. The site also hosted a presidential debate in 2008.
Michael Abbott, owner of All Ears, Inc. (Los Angeles), chose to utilize a pair of Yamaha DM2000 digital consoles for audio control.
“The dual DM2000s were chosen for the presidential debate specifically to provide two separate audio streams,” states Abbott. “Size and audio I/O capabilities also played a key role in the set up. We routed six Yamaha AD8HR 8-channel preamps to eight groups—four for the house mix and four for the broadcast pool truck.”
In addition, Dugan-MY16 automatic mixing controller cards were inserted for the 24 town hall participant microphones, as well as the moderator and candidate microphones.
Yamaha Commercial Audio
Tuesday, October 16, 2012
It Depends: Deciphering Amplifier Power Ratings
Click here to view/download a printable pdf of this article.
How much power can an audio amplifier produce? As you might expect, “it depends.”
I will approach this from two angles—in theory and in practice. This article will deal with the theory. Part 3 will show how things play out in the real world.
Importance Of Efficiency
Amplifiers don’t make power. They convert it. Any audio power that comes from your amplifier must in turn come from the utility outlet that it is connected to. This is why the wire gauge of the line cord matters, and why long extension cords can be a problem.
I showed in part 1 how the power equations calculate the power from the voltage and current, or from the voltage and the load resistance.
These simple forms assumes a purely resistive load. That’s good, because that is how amplifiers are usually tested to determine their power rating.
This is the “apparent power” from the source. Apparent power (in volt-amperes) assumes that the voltage and current are in phase, which is only the case for a purely resistive load. The actual power in watts is likely less than the apparent power in volt-amperes given the nature of real-world loads. I’ll assume a resistive load for now and use watts as the unit.
The power equation says that the maximum continuous power from a 120-volt RMS, 15-amp outlet is 1,800 watts. Substitute a 20-amp circuit breaker and the maximum continuous power is 2,400 watts. Note that 20-amp circuits require special outlets and plugs. Since we are talking about theoretical maximums, I will assume a 20-amp circuit.
If the amplifier were 100 percent efficient, it could produce 2,400 watts (34 dBW) of audio power from the 120-volt, 20-amp outlet. The conversion efficiency of modern switch-mode amplifiers (Class D and its variants) can exceed 80 percent, meaning that an amplifier rated at 2 kW continuous is a possibility.
In effect, the largest amplifiers can produce sine waves that are very close in voltage, current and power to a household electrical circuit in the USA - an incredible achievement in amplifier evolution. Of course utility power is a 60 Hz sine wave. Music and speech signals are broad band, and will produce considerably less power than a pure sine wave due to their higher crest factor.
Let’s go with this theoretical 2,400-watt amplifier (34 dBW) for now. The wattage puts the best face on the power rating (and looks good on the spec sheet). The dB rating (level) is much more useful to the system designer. But how much power can you really expect from the amplifier? As I showed in Part 1, this “best case” rating provides a reference that must be de-rated by the system designer.
What Do We Really Get?
The amplifier’s job is to accurately reproduce the signal voltage presented to its input. It’s not technically correct to call it a power amplifier, because the output power has nothing to do with the input power - only the input voltage.
It has to amplify this voltage while sourcing the current being demanded by the load. As I showed in part 1, this gets tougher as the load impedance drops.
For a constant voltage interface (any modern power amplifier), current is a responder. It is the “result” of the drive voltage and load impedance.
Since the load impedance is fixed (unless your loudspeaker overheats), the current (and the resultant power) can only be changed by adjusting the drive voltage to the amplifier. For this reason, I always do my initial assessment of an amplifier based on its maximum sine wave output voltage.
Next I consider the minimum load impedance for which the amplifier can sustain this voltage. The maximum output voltage can be determined from the 8-ohm power rating with the power equation, solved for voltage.
This is easy to verify with an oscilloscope and a (big) dummy load and it is normal to find excellent correlation with the amplifier’s published specifications.
I looked at several of the largest available amplifiers and assessed their voltage output. I won’t compare them here, but the broad conclusion is that an increasing number of them have approximate maximum sine wave voltages in the 130-volt RMS range, which is a peak voltage (multiply by 1.414) close to 200 volts.
The term “200 volt rails” is gaining popularity among the amplifier crowd. I’ll assume that such a voltage is possible in this article. I will verify it in Part 3.
A sine wave of 140 volts RMS will produce these wattages into a resistor from an ideal amplifier (one that can source the required current):
2,500 watts at 8 ohms
5,000 watts at 4 ohms
10,000 watts at 2 ohms*
* theoretical value only!
You can forget about the 10 kW into 2 ohm sine wave rating for lots of reasons, not the least of which is that you can’t draw that from a typical electrical circuit and the chances are slim that you have a true 2-ohm resistive load. 2,500 watts is within 0.2 dB of the maximum power from the electrical outlet.
That’s “dead on” in amplifier world. Note that all of these rated powers exceed the 2,400 watts that is available from the electrical outlet, especially if the amplifier has multiple channels. At these wattages, the utility power may be the limiting factor with regard to what amplifier can do.
To assess the music/speech output voltage, I’ll take the rail voltage and convert to dB, and subtract the crest factor of program material. I’ll be generous and assume a crest factor of 10 dB, which is typical of slightly clipped pink noise. I’ll then convert the level back to voltage.
As you can see, the power drops dramatically when you substitute real-world program material for the sine wave. Now, keep in mind that sometimes real-world program material IS a sine wave. A synthesizer can produce very low crest factor signals that can trip circuit breakers and burn-up a subwoofer connected to the amplifier.
The vast majority of loudspeakers in the marketplace have rated impedances of 4 ohms or higher. The average impedance is higher yet, which is what the amplifier sees if you are playing broadband program material (speech or music). So, to say that we can draw 1 kW from an amplifier is being generous.
It would not be unusual to be able to drive our 2,400-watt amplifier to clipping into a modern line array box using a pink noise signal. Does that mean that the box is “handling” 2,400 watts? No. The high crest factor of the pink noise and the higher real-world average impedance of the loudspeaker means that the power flow is far less than 2,400 watts. It is handling the full voltage swing of the amplifier, but not its full output power.
The high crest factor signal and real-world loudspeaker impedance can allow me to access the full voltage swing of a theoretical amplifier rated at 5 kW/channel into 4 ohms.
Bottom line? The amplifier will run out of voltage swing before it runs out of power.
Crest Factor & Duty Cycle
If the power from a source cannot be sustained over time, it may be interrupted periodically to avoid damage to the source or the production of excessive heat in the load. Examples include pumping the brakes on your car when descending a steep hill, or breaking a long weld into shorter segments.
A source that cannot run continuously without overheating may be given a duty cycle rating. Playing a repetitive waveform (like a kick drum) is like pumping the brakes on your car. The power and heat production are reduced. That’s a good thing, since otherwise we’d be tripping circuit breakers and burning voice coils.
In contrast, the largest power ratings on an amplifier spec sheet result from “Burst testing.” This is a method developed for measuring cell phone signals, and it is also used on power amplifiers. A burst test hits the amplifier with a signal that only lasts a few milliseconds. These bursts produce some very high amplitude peaks, but only for a very short period of time.
Looked at another way, burst testing can prevent the circuit breaker from tripping (a good thing) and allow our 2,400-watt amplifier to drive a 2-ohm load. This theoretically doubles the power to nearly 5 kW from a single amplifier channel. Is this a legitimate power rating for the amplifier?
The moment-by-moment voltage amplitude values of an audio waveform can be very high. Multiplying the instantaneous voltage by the instantaneous current yields the instantaneous power (and some impressive numbers!). Instantaneous power is a means to an end, not the end itself. It must be integrated over time to find the root-mean-square voltage and the average power (a less impressive number!).
We can all pass our finger quickly through the flame of a candle without being burned, but we wouldn’t boast about being able to “handle” the heat of the flame. The short-term transients in the audio signal may not pose a thermal danger to the transducer, so technically they are not over-powering it. They may, however, cause excessive excursion, which is another failure mode of loudspeakers.
While burst signals can have very high amplitudes, they are quite short in duration. The waveform produced by a kick drum is made up of multiple frequencies that are not phase coherent due to the non-linear phase response of the subwoofer. This makes the crest factor high, or looked at another way, the duty cycle low (should drummers have duty cycle ratings?).
Either way, the power output from a kick drum is not all that high. A far more punishing waveform would be the continuous sine or square wave output from a synthesizer. This is the only way that you will challenge an amplifier to produce its full rated power, and you may burn up your subwoofer in the process.
Don’t get me wrong. It is a good thing for an amplifier to be able to produce waveforms with very high instantaneous power.
It is not often clear to consumers what this means and under what conditions it is measured (the fine print). All they see is a huge number with “watts” after it and may assume that it is a continuous rating.
There are other issues that complicate the generation of power. Reactive loads (like loudspeakers and transformers) produce a phase shift between the voltage and current. This reflects some of the applied power back at the amplifier and reduces the power delivered to the load. If you’ve ever used a reciprocating saw on a flexible panel, you have experienced mechanical reactance first hand.
So, there are several factors that decimate and nibble away at the rated power of a multi-kilowatt amplifier. The good news is that modern multi-kilowatt amplifiers have gotten pretty smart at being able to allow their massive instantaneous power to be utilized without tripping circuit breakers and burning up loads. I’ll revisit this in part 3.
Need For Conversations
To summarize, it is theoretically possible for a highly efficient audio power amplifier to produce continuous sine wave power in the 2 kW range. For it to actually have to do this is unlikely, given the nature of music and speech signals and the real-world impedances of loudspeakers.
Rating the amplifier based on a very low load impedance, tone burst signal and in linear units (”watts”) is definitely putting the best face on it. Just remember that the “KiloBlaster 10000” gets it rating based on the summed power from multiple channels under these “non typical” conditions.
Since no standard exists for “burst testing” amplifiers, you can bet that it is done differently by every manufacturer. This doesn’t make the numbers meaningless, but you won’t be able to use them to compare different makes and models. You’ll have to compare them the old-fashioned way - listening tests using a massive subwoofer (be sure to warn the neighbors).
In reality, the “KiloBlaster 10000” amplifier from one manufacturer may produce the essentially the same performance as the “SpeakerWelder 12000” from another, and the “ConeMelt 6000” from yet another. Their rated outputs are within 3 dB of each other, and this may not be audible under real-world conditions. They may actually measure about the same if tested in the same manner.
Our industry needs to have some serious conversations about power and power ratings for such numbers to be useful for comparison shopping. For now, give me continuous sine wave ratings that I can use to design sound systems. The reputable manufacturers do this already, but you’ll probably have to read the spec sheet, not the sales brochure, to find them.
Why does any of this matter? We need to keep it real. Idealized rating methods generate misunderstanding and unrealistic expectations among audio practitioners. The consultant who won’t specify an amplifier “under 2 kW” or a loudspeaker with a maximum SPL rating “less than 140 dB” is missing the boat and likely passing over some very good products.
The burden is on the audio professional to decipher the power rating into what they can expect when the amplifier is in their customer’s rack, not on the test bench.
In part 3 I will lay aside the theories and the musings and test some commercially available units under real-world conditions. Someone please warn the neighbors.
Pat & Brenda Brown lead SynAudCon, conducting audio seminars and workshops around the world in addition to providing web-based training at www.synaudcon.com.
Click here to view/download a printable pdf of this article.
Shure Introduces New Rechargeable Battery Accessories
Compatible with several Shure wireless system components
Shure Incorporated has introduced new rechargeable accessories: the SBC210 portable charger and SBC-DC bodypack power insert.
Coupling solid reliability with improved efficiency, the new solutions offers intelligent power management for extended usage times and battery life.
The SBC210 has a compact, rugged design and is available in a convenient desktop unit. Built with a rapid charging function, the portable accessory can charge two SB900 batteries to 50 percent capacity within one hour.
A full charge for both batteries can be achieved within three hours. SB900 batteries are compatible with the Shure P9RA and P10R wireless bodypack receivers, the ULX-D digital wireless handheld transmitters, and the UR5 portable diversity receiver.
Compatible with SB900-powered devices, the SBC-DC bodypack power Insert connects to a PS41 power supply for consistent and continuous operation without batteries. The SBC-DC can be used with P9RA and P10R wireless bodypack receivers, the ULXD1 wireless bodypack transmitter, and the UR5 portable diversity receiver.
In designing the SBC210 and SBC-DC, Shure built on the benefits of the company’s existing rechargeable products. All Shure rechargeable products have precision metering, enabling users to track remaining battery life on the transmitter and receiver displays in hours and minutes—accurate within 15 minutes—for increased reliability and more definitive monitoring.
Additionally, they combine Lithium-ion chemistry with Shure battery circuitry, resulting in zero memory effect. Batteries can be recharged at any time, and a complete discharge is never necessary.
“Our research showed that, historically, rechargeable products didn’t necessarily have the best reputation among audio professionals because of their perceived lack of reliability. We were determined to change that with these new accessories,” said Stephen Kohler, director of product marketing, Shure Americas Business Unit. “Because Shure’s new solutions provide a highly accurate display of remaining battery life in hours and minutes, users can now have the high level of confidence that they did not have before.”
Pricing and Availability:
SBC-DC DC power insert for SB900-compatible bodypack—$118
SBC210-US dual portable rechargeable battery charger—$289
SBC200-US dual docking charger with power supply—$274
SBC200 dual docking charger (power supply not included)—$200
SBC800-US eight-bay battery charger—$548
SB900 Lithium-Ion rechargeable battery—$118
SB900-8 eight pack of Lithium-Ion rechargeable batteries—$820
Posted by Keith Clark on 10/16 at 03:42 PM
Dan Dugan Sound Design Updates Economy Mixer With Model E-1A Automatic Mixing Controller
Provides up to 16 channels of transparent automatic mixing
Dan Dugan Sound Design has introduced the Model E-1A automatic mixing controller, which builds on the architecture of the existing Model E-1, adding increased DSP power to provide up to 16 channels of transparent automatic mixing.
As with Dugan’s larger D-series automixers, the new Model E-1A allows users to divide the unit into three separate automixers, with each set having its own set of master buttons on the software control panels.
The Model E-1A replaces the Model E-1. Model E-1 owners having serial numbers 417 and above already have the hardware and will be able to update their units to all the new features via a firmware upgrade.
The Model E-1A includes the upgraded control panel for Java, a real-time remote control panel, while a recently announced iPad app (purchased separately) brings touch control to the control panel.
In addition to eight channels of analog I/O, the Model E-1A has two pairs of ADAT connectors. One pair may be used for digital I/O with the second pair utilized for linking, or the link connectors may be repurposed for an additional eight audio channels.
“In the past year, the processing power of Dugan products has been dramatically increased,” says Dugan. “As we were working on the Dugan-MY16 card for Yamaha, several options were opened for us to enhance the capabilities of our other units. The Model E-1A is the result of extensive engineering research, accommodating our customers’ requests for more audio channels and extra mixing groups.”
Dan Dugan Sound Design
QSC Promotes Jatan Shah To Executive VP/COO & Barry Ferrell To VP, Cinema
Show to oversee several key aspects of company; Ferrell takes the reins of cinema group
QSC Audio Products has announced the promotion of Jatan Shah to executive vice president/chief operating officer as well as the promotion of Barry Ferrell to vice president, cinema.
In his new role, Shah will oversee the company’s finance, R&D, manufacturing, supply chain, IT, and legal functions.
“Since joining QSC, Jatan has made unparalleled contributions to our success through his leadership and critical thinking. He has led many key efforts across the organization in the areas of financial management, product development, and an operations transformation,” states Joe Pham, QSC chief executive officer. “His exceptional business skills and leadership traits make him an invaluable member of our executive team as we move forward in building the future at QSC. I am thrilled and very grateful to have a professional of his caliber working with us.”
Shah joined QSC in 2010 and has served as chief financial officer and chief technology officer, leading the finance, R&D, legal, and IT departments. Prior to joining the company, he served for five years as senior engagement manager at McKinsey & Company, a global management consulting firm recognized as one of the most prestigious in the world. Shah spent the previous five years as a manager at United Technologies Corporation, a provider of high-technology products and services to the global aerospace and building systems industries.
“We have very high aspirations for QSC in achieving long term growth and I am very excited to be a part of the executive team which will be taking the company to the next level,” says Shah. “I look forward to the opportunities and challenges that my new role presents, and the ability to further solidify the foundation of QSC’s Finance, IT, Legal, Manufacturing, Supply Chain, and R&D functions to enable our growth aspirations.”
Ferrell began his career at QSC in 1990 as an applications engineer and was the first technical hire at the company in the sales and marketing department. After holding a number of different positions there, he assumed the leadership role of the Cinema Group at QSC in 2009.
“Barry has led our Cinema efforts in every way, including the development of many outstanding products for this important marketplace,” Pham says. “I am very excited for Barry to be at the helm as we continue to offer our next generation of complete Cinema solutions.”
Over his 22-year career at QSC, Ferrell has served as the product manager for every single cinema product developed at QSC. This includes the DCA amplifiers, DCM crossover/monitors, DCS loudspeakers and most recently the DCP line of digital cinema processors.
His insight into cinema products is driven by his knowledge of the growing needs of the marketplace and by his practical experience. He began his career in cinema and professional audio in 1980 when he was hired as an usher at a local cinema and quickly moved in to the projection booth.
In 1985, Ferrell worked for National Amusements as a union projectionist out of local #327 before moving to Omaha in 1987 to take over the console pre-wire department at Ballantyne Strong. After building and shipping several thousand projection consoles, he decided to join QSC.
“I’m very proud of the full systems solutions for cinema that QSC has developed over the years – from amplifiers to loudspeakers to digital cinema processors – we offer the marketplace a total cinema solution,” says Ferrell. “I look forward to meeting new challenges in this market.”
He is involved in the activities of the International Cinema Technology Association (ICTA) and is a frequent contributor to their technical seminars, is a past president of the organization and currently serves on the board of directors.
Renkus-Heinz Iconyx Overcomes Acoustical Challenges At Denver’s Clyfford Still Museum
Reverberant environment tamed by steerable array loudspeakers
One of the giants in post-WWII American painting, Clyfford Still dropped out of the commercial art world in 1951. When he died in 1980, he willed entire collection to an American city willing to create a permanent home for it.
More than three decades later, the Clyfford Still Museum opened its doors in downtown Denver. The 28,000-square-foot steel and concrete building houses more than 2,400 of Still’s works, as well as a collection of the artist’s journals, sketchbooks and archives.
Visitors enter the museum through a large glass-lined lobby whose windows extend from its tiled floors to its concrete ceiling. The beautiful architecture, while visually appealing, creates a highly reverberant acoustical environment that is anything but conducive to the large-screen video presentation that runs in the museum’s entry.
Denver-based Empowercom was retained by the museum’s planning commission to address the lobby’s challenging acoustics. As Empowercom vice president Terri Jackson explains, the selection of Renkus-Heinz Iconyx steerable array loudspeakers for the application was a logical choice.
“The content management committee on the project had suggested the Iconyx system, and everyone involved unanimously agreed they were the only speakers that would meet the needs of the space,” says Jackson. “Being able to steer the sound away from the abundance of reflective surfaces was key. Using the Iconyx, we were able to focus the sound to a concentrated area directly in front of the screen, rather than create a cacophony across the entire lobby.”
Jackson adds, “The program material contains both narration and music, and the Iconyx delivers on both spoken word intelligibility and musical performance.”
The low-profile design of Iconyx also helped to make it an ideal fit, says Jackson. “It’s a very high-end space, and the Iconyx really fits in with the décor,” she notes. “It’s an elegant, low-profile design that actually blends with the surroundings.”
Soundcraft Si Compact 32 Console Provides Solution For New York High School Auditorium
Upgrading from analog to digital within the right pricepoint
Sound contractor Brown Sound Equipment Corp. of East Syracuse, NY recently installed a new Soundcraft Si Compact 32 digital console to replace an outdated unit at the East Syracuse-Minoa High School auditorium.
“Originally the district had budgeted for a 32-channel analog console—but they wanted to run 44 channels of wired and wireless mics from the stage,” explains Jim Messinger, co-owner of Brown Sound. “The original idea meant running lots of copper from the stage with fan-outs at the board, with the person at the console manually patching in whatever inputs were needed for each particular event. We knew there was a better solution out there.”
Working with David Dusman of Sigmet, Soundcraft’s regional sales rep firm, Messinger took a look at the Si Compact 32. “It was apparent this was the right solution, was within our budget and would enable us to upgrade from analog to digital,” Messinger says.
The upgrade was part of an overall remodeling of the auditorium’s audio capabilities, brought to fruition under the oversight of Amanda Thomas of King+King Architects, Syracuse, NY, Jon Helberg, electrical engineer at IBC Engineering in Rochester, NY and East Syracuse-Minoa High School music director Steve Culhane.
In order to get 44 channels into the 32-channel Si Compact 32, Brown Sound also opted for a Soundcraft Compact Stagebox. “We configured the Stagebox to have 48 inputs to send to the console, with eight returns for the BSS Soundweb London processors in the stage rack,” Messinger notes. “It connects to the console via two Cat5 cables—a main and a backup—feeding into a MADI card in one of the Si Compact 32’s expansion slots.
“Using just the two Cat5 cables from the Stagebox to the console really simplified the installation—we were able to do a lot of the preliminary work off-site—and saved a great deal of time.”
The operator of the Si Compact 32 console can choose up to 32 of the microphones he or she wants to use—more than enough for any school event. Eight outputs from the console are fed into a Lexicon I-O/FW801S FireWire recording interface that’s connected to an iMac for 8-track live recording.
“We knew the Si Compact 32 was small, but we didn’t realize just how much space it saved until we put it in the Secure Cabinet locking rolltop cabinet that King+King had specified for the install,” Messinger says. “The cabinet was specified before we had finalized the decision on the console and the Si Compact 32 just looked tiny in that huge space.
“However, this turned out to be an advantage. Originally we were going to place a combination CD/iPod player and the I-O/FW801S under the console where they would have been hard to reach. Instead, I had room to place them above the console in a ‘bridge’ I constructed, which makes them a lot easier to access. There’s also room for future expansion if needed.”
Brown Sound Equipment