(Updated 3/2/12: An earlier version of this article incorrectly credited the images to Sievers Audio. The images were created and supplied by the writer.)
We have all heard this, “Come see the newest or greatest gadget. It slices, it dices it…” Well, you get the picture. Sometimes these things are a hit out of the park, and sometimes they are just great marketing.
Loudspeaker companies are notorious for making something very subjective seem like an innovation of a lifetime. Still we need to keep an eye on new innovations and try to sift through the hype and get to the real deal.
That's why when we hear a buzz about something fantastic --- something said said to redefine physics “as we know it” --- we are met with two options: skepticism or hope.
Audio is all about compromises. If you know anything about the true nature of audio you will not be surprised. It comes down to who can make the best-sounding compromise per size and price.
Which brings us to the subject of this article. A new audio company is putting some “out-of-the-box” technology together as a package, and it's generating quite a buzz in the pro audio industry. Sievers Audio is the name of the manufacturer, and it's their new speaker design that is creating quite a stir. The company held private demos in during the Winter NAMM Show in Anaheim. According to those who attended, the performance was quite impressive. Still, the claims from the company seem outlandish. A company brochure states that a modest sixteen-box system --- four powered mid/high boxes, and four subs per side can run off a single 120-volt, 20-amp circuit. Even more interesting is the claim that the system can fill a 5,000-seat room with 124 dB peak output while producing no dead spots, and eliminating the need for acoustical treatment.
Skeptical? Us too.
Let's start by looking at the technology driving the speaker. Most conventional speakers use what we call a pistonic movement of a diaphragm so that the whole unit pumps back and forth at the frequency that we want to reproduce.
The Sievers is using what is called a Distributed-Mode Loudspeaker (DML) for the mid-frequency range. DML, developed years ago by NXT, is a very complicated mathematical conundrum as it uses the resonance modes of a panel that combine in order to produce the frequencies without the normal piston action. This technology produces a large, thin, light-weight driver system that has some special characteristics; among them being that it operates in a very wide dispersion pattern (170 degrees in this case), with close-to-line-source drop off in level at distance.
For the high-frequency speakers Sievers is using line-array-style ribbon drivers with a twist. This is what is called an Air Motion Transformer designed by Dr. Oskar Heil. Instead of having a stretched flat ribbon that can great deal causing a lot of stress on the diaphragm at higher levels, the ATM uses an accordion-like set up that squeezes the air as the folds shift back and forth. This style of driver has a lot of benefits; mainly the lack of stress based on the reduced movement needed to generate a given SPL. Like DML, this technology gives a very wide pattern with close-to-line-source drop off in level at distance.
This type arrangement is designed to give the Sievers loudspeaker an extended range --- beyond 20 kHz. Anyone who knows the truth of audio knows that most line arrays don't produce much above 10 kHz without a bunch of break up.
Subwoofers, not just bass speakers, but those that produce true sub frequencies usually require a very big cabinet and a lot of excursion to pump air. Even so, the Siever's system claims to produce 20 Hz of concert-level output from a box the size of a microwave oven? 13”x24”x13” are the specified dimensions for the subwoofer that comes with the Sievers Audio system. The last thing I remember that played like that was the old Servo-Drive speakers.
The Sievers Audio subwoofer is based on Linear Array Transducer technology developed by Tymphany. This transducer is unusual in that it acts as a pump designed to move air using several discs attached to rods that are connected to an electric motor.
So the new Sievers Audio system is not made up entirely of new technologies. The company claims it has done thorough testing and evaluation, with supporting documentation on all the physics. So what are the compromises? In my opinion, they have made some to make the system sound more musical. For example, flat panels are known for not sounding real musical in the high frequencies. So Sievers added the ribbons to fix that. And the small size of the woofers may produce impressive frequency range, but smaller boxes mean less output. Conventional wisdom would tell you that you need to buy more boxes to get the concert-level SPL.
Of course, the bottom line is “How does it sound?” Well I have heard from some trusted friends that it sounds fantastic. And as I write this I'm getting ready to travel to the West coast to hear them for myself.
When I get back, I'll report my findings.
- BIO -
David McCauley is director of design development for AE Global Media, an audio, video and lighting systems integrator based in Charlotte, North Carolina
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