Jun 22, 2010 2:13 PM, By Bob McCarthy
Large Loudspeakers (Greater than 8in.)
We can take any installation or touring box, stick it in the ceiling, and call it a “ceiling loudspeaker.” A big ballroom with high ceilings and high SPL requirements favors such an approach, but we are going to limit our discussion here to those models designed exclusively for ceiling applications. This limits the maximum driver size to about 12in.
Moving up to an 8in. loudspeaker extends the bass response. Adding a high excursion woofer and expanded enclosure volume take it even further. All of these are found in the Boston Acoustics VSi 5830. This is a three-way, 8V unit for home or short-distance applications. The pivoting tweeter is a 1in. aluminum dome, and the midrange is handled by a 3.5in. stamped steel copolymer driver. The LF extension reaches down to 48Hz and can be equalized with an integral switch to compensate for the loudspeaker’s position relative to corners. When driven at 100W, this loudspeaker should be able to produce 109dB SPL at 1 meter, making it competitive in the home theater or loud retail market.
No name in our industry is more synonymous with coaxial than Tannoy. Unveiled at InfoComm 2010, the new CMS 1201 ceiling loudspeaker is built around a 12in. high-power Dual Concentric driver with a ferrofluid-cooled Neodymium magnet and a new HF waveguide for smooth, uniform response over a 90-degree coverage area. To simplify implementation, Tannoy’s free Ease Address design software can calculate optimum spacing and performance from a few simple parameters. The CMS 1201 is offered in low-impedance (CMS 1201DC) and a 70V/100V transformer version (CMS 1201DCt). Various standard transformer taps are configurable before screwing the driver assembly into the backcan. Later, if a level change is required, the hinged baffle leaves both hands free to make adjustments. While this does not look or feel like the traditional ceiling loudspeaker/backcan assembly, a great deal of engineering has gone into ease of installation for applications having very high ceilings or high SPL requirements. The CMS 1201 has enough power to pump disco into retail clothing stores so parents will hand the kids their credit card and run.
Not every loudspeaker fits in the standard mold. Here are a few specialty items that merit attention.
All the loudspeakers featured above tout their capability to have wide coverage. But what about those cases where we want narrow coverage from above? Do we have to stick a large format box with a horn into the ceiling? Enter the Holosonics Audio Spotlight, an entirely new approach to ceiling loudspeaker design. This is a specialty product that provides highly controlled directionality from a flat surface. The loudspeaker is a 1/2in.-thick flatpanel, and the directional control comes from ultrasonic soundwaves that combine in the air to create audible sound. The signal that drives the loudspeakers is beyond our hearing (but quite popular with bats), yet these waves modulate the air to create audible sound in a very precisely controlled area. This allows for directional control without the depth of horns or multiple drivers to do the shaping. Naturally your standard power amplifier won’t be driving this. The loudspeaker system consists of the easily installed flatpanel and a small specialized controller. Just add line level audio and mix.
Applications for such a system include any place where you want sound in a small area that does not spill into others. Examples might include museums or exhibitions where attendees can hear audio where they are standing and then walk out of it to the next station. Don’t look for it to rock your world. This design is limited in frequency range and can reach only 85dB SPL at 1kHz, although a new version, just released, can generate an additional 6dB.
Two versions are available in black and white or custom print finishes. The AS-16 provides the more narrow coverage, and the AS-24 can be used at longer distances and has more spread.
The Martin Audio CS10 is a specialty product that we can expect to become more commonplace in the future: the ceiling-mounted subwoofer. OK, it’s not for the dentist office, but it definitely will be found in home theaters, retail, bars, and commercial entertainment applications. The CS10 enclosure is made from a fire-retardant MDF that mounts on three convenient brackets. You will need some advance planning for the extra real estate, but it will fit in the opening of a single 24”x24” ceiling tile with 9.5in. of vertical clearance. A single 10in. driver in a reflex enclosure runs from 32Hz to 150Hz (-10dB) and can generate up to 115dB SPL continuous. If the client wants to shake the rafters, the CS10 is in a great position to do it.
If you’re standing on the floor, the Meyer Sound Stella-8C looks like every other ceiling loudspeaker. From up in the ceiling, it still looks like a standard backcan, but inside the can is a very different animal: a self-powered two-way loudspeaker, driven with a balanced line and powered from an external DC supply. The Stella-8C is an actively crossed, phase-aligned two-way loudspeaker (8in. to .75in coaxial tweeter). The onboard electronics contains the signal processing to optimize the loudspeaker’s response and bi-amplified driver protection. The loudspeaker is fed both a balanced audio signal and a DC power feed from a dedicated power supply (the Stella-188). The 12VDC-to-18VDC line is classified as low voltage so that conduit is not required. The sonic advantages to amplifying your loudspeakers locally, avoiding transformers and reducing noise through balanced lines, are substantial. The Stella-8C (and sister 4C) were engineered primarily for use in Meyer Sound’s Constellation electroacoustic architecture, which sends unique signals to each loudspeaker. In cases where multiple channels of audio are desired for different ceiling loudspeakers, the independent channels capability of the self-powered approach makes it more economically competitive.
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