Meyer Sound MM-4XPD Gives Direction to Celtic Woman Tour and Virtual Reality Environments at KAUST


1. Celtic Woman tour
2-4. KAUST
5. MM-4XPD sound field at 160 Hz
6. MM-4XPD sound field at 315 Hz
7. MM-4XPD sound field at 4 kHz

"We needed to solve two big problems. First we needed to control audio leakage from one area to another in a large, open space. We also wanted to control reflections from hard surfaces, including the video displays and a large nearby window. The MM-4XPD proved to be the perfect solution."

- Peter Otto
Head of Calit2's Sonic Arts Group

At first glance, the North American tour of Celtic Woman appears to have little in common with the virtual reality environments at a high-tech university in Saudi Arabia. On closer inspection, a keen observer would note that both rely on Meyer Sound's new self-powered MM-4XPD miniature directional loudspeaker to project low-distortion, wide-bandwidth sound precisely where it is wanted, while minimizing audio leakage and interference with reflective surfaces.

Meeting similar performance standards as the popular MM-4XP miniature loudspeaker, the MM-4XPD adds the advantage of a hypercardioid coverage pattern, providing a unique solution for controlling sound in highly reverberant open spaces. With a 10 dB attenuation between the front and the back of the loudspeaker, this new technology reduces excitation of the room even at low frequencies, and enables sound designers to bring audio clarity to notoriously challenging environments that include restaurants, bars, trade show booths, retail spaces, and museums. The MM-4XPD features a four-inch-square faceplate and weighs only 5.2 lbs, with an impressive peak output of 113 dB SPL.

The MM-4XPD effectively solved a vexing problem on the recent Celtic Woman tour. "The singers all wear sensitive omnidirectional condenser headset mics, sometimes with 13 on stage at once," says Wayne Pauley, the tour's FOH engineer. "In-ear monitors prevent monitor bleed, but when the singers moved close to the front fills the backwash threatened to cause feedback and phasing issues."

To address the problem and ensure the best possible sound for VIP ticketholders in the front rows, sound provider Blackhawk Audio replaced the frontfill loudspeakers with 12 MM-4XPD directional loudspeakers midway through the tour. "The change not only improved gain before feedback, but it also let me optimize the sound quality for the front-row audience," says Pauley. "Now I don't have to make huge cuts in the EQ just to keep the system stable when singers move downstage."

The MM-4XPD achieves its remarkable hypercardioid directional characteristic using a patent-pending passive design that employs a single four-inch driver manufactured at Meyer Sound's Berkeley headquarters. This approach eliminates the added bulk and costs of designs that require a second active driver.

The hypercardioid coverage pattern, combined with excellent voice intelligibility and wide-bandwidth reproduction, makes the MM-4XPD well-suited for demanding applications such as the virtual reality environments at the new King Abdullah University of Science and Technology (KAUST) in Saudi Arabia. Audio systems for these leading-edge, immersive AV environments were designed and prototyped at the California Institute of Telecommunications and Information Technology (Calit2) at the University of California, San Diego.

"We needed to solve two big problems," observes Peter Otto, head of Calit2's Sonic Arts Group. "First we needed to control audio leakage from one area to another in a large, open space. We also wanted to control reflections from hard surfaces, including the video displays and a large nearby window. The MM-4XPD proved to be the perfect solution."

Other loudspeaker systems were investigated for the KAUST installation, but involved unacceptable compromises. "We tried other approaches to restricted coverage but found the digital signal processing introduced unacceptable delays," adds Otto. "Also, they did not provide the robustness we're accustomed to with Meyer Sound products." Sound equipment installed at KAUST also includes Meyer Sound's MM-4XP miniature loudspeakers and UMS-1P subwoofers.

Like the MM-4XP miniature loudspeaker and the MM-4XPV miniature loudspeaker with volume control, the MM-4XPD utilizes a remote 48V DC power supply. Because the amplifier and signal processing circuits can store DC and tolerate voltage drops, installers can use light-gauge cables over long runs. Installation costs are greatly reduced while preserving the clear performance advantages of self-powered systems. A single MPS-488 rackmount eight-channel power supply provides balanced audio and DC power for up to eight MM-4XP family loudspeakers, with connections over a single cable terminated with a five-pin connector (Switchcraft EN3).

February, 2010





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