DiAural Demo Converts Skeptic

Advances in audio reproduction typically proceed with tiny steps that, in time, add up to major systemic improvements. In this industry, quantum leaps in basic technology rarely happen. DiAural Doppler decoding may be one of them.

Five weeks ago we reported that Ray Kimber, of Kimber Kable fame, and his financial partner, Bruce Bastion, were in the process of bringing a new loudspeaker technology to market. DiAural, as they've named the technique, is claimed to eliminate what Kimber calls Doppler-encoding distortion---the modulation of high frequencies by low frequencies of higher amplitude.

According to Kimber, this encoding takes place in the microphone, survives intact throughout the recording and playback chain, and, if left undecoded, seriously detracts from any audio system's verisimilitude. The DiAural technique, developed by designer Eric Alexander, performs decoding at the speakers themselves, using a couple of common parts configured in a novel way that enables a woofer and tweeter (or woofer, midrange, and tweeter) to "talk back" to each other, freeing them to jointly produce sounds more like those that originally impinged on the microphone. The DiAural circuit replaces the traditional crossover network, which means the drivers are connected directly to the amplifier. All of which made for an interesting telephone discussion I had with Kimber before writing this story.

Hearing the technology in person is quite a different experience. Last week, I was privileged to be the first of a string of journalists to visit Kimber's plant in Ogden, Utah for demonstrations. An impending patent approval---Kimber was expecting the call the day I was there---has prompted him to line up reporters to get the word out. Gene Pitts, Corey Greenberg, and Ken Kessler, among others, are all scheduled for auditions.

The word is this: DiAural is for real. No mere marketing hype, the technique enables otherwise ordinary loudspeakers to deliver unprecedented musical dynamics, detail, imaging, and clarity in a way I would never have thought possible. It also enables them to fill an enormous space with seemingly effortless sound.

In a partially walled-off area in the back of his cavernous building, Kimber had set up a temporary auditioning space. (A dedicated listening room is under construction.) A nice system---Denon DVD-5000, and Mark Levinson No.380S preamplifier and No.335 power amp---delivered the signals through Kimber Select interconnects and speaker leads to a pair of unimposing two-way speakers mounted on steel stands. The drivers were 6.5" Dynaudio woofers and 1" dome tweeters---pretty generic stuff---and the unfinished enclosures, built of MDF right there in the shop, had horizontal ports near the bottom of the front baffles. The roughly 2-cu.-ft. boxes were built to Thiele-Small parameters, Kimber told me, but the resemblance to normal loudspeakers stopped there.

For all of one morning and most of an afternoon, we rocked the place with every imaginable type of music, including delicate vocals and chamber pieces, huge, bombastic symphonic works, incredibly rhythmic Latin tunes, and war-horse rock recordings. Imagine, if you will, the delicacy and shimmer of the best electrostatics, the pinpoint imaging of the best minimonitors, and the drive and slam of the biggest dynamic systems. Imagine localizing instruments in space as if they were really present---and sustaining that localization as you got up, turned around, walked away, and went to the other end of the building. The whole affair was quite extraordinary.

But it didn't end there. Just inside the plant's wide industrial door was a pair of large three-way professional horn loudspeakers, of a type that might grace the rafters at any arena rock show. Eric Alexander had also worked his magic on these, bypassing a disturbingly complex crossover network and ignoring the manufacturer's admonition to use the speakers only with the recommended processor. Instead, an old Technics SL-P1300 CD player was connected to an even older BGW power amp, which in turn was hooked up to the speakers through maybe 30' of 8TC cable. Kimber rolled open the door, popped a disc in the player, and motioned for me to go outside.

We walked away from the building about 50 yards and turned around to hear Jethro Tull's Thick as a Brick with more clarity and fidelity than I have ever heard. The midrange was especially lucid, something that took me completely by surprise. Pro loudspeakers tend to sound raspy, nasty, and congested, but these were clean and clear as the Utah air. It was exactly the sound audiophiles wish for when they attend large concerts, and it demonstrated to me that it is entirely possible to move vast quantities of air without sacrificing sound quality. Kimber even turned it up loud enough to bounce the sound off a building 100 yards away, and the echo was also startlingly clear. So was the reflection off the inside of the door when he closed it.

I have long believed that improving transducers---microphones and loudspeakers---is the next frontier in audio. Eric Alexander and Ray Kimber have validated that belief for me. DiAural will work for almost any variety of dynamic loudspeaker, Kimber says. Transformer-coupled electrostatics and hybrids probably aren't suitable for the technique, but he claims Alexander is near completion on a line-level analog circuit and a digital signal-processing technique that will duplicate what they have done with two ordinary speakers. Were I a loudspeaker maker, I'd postpone any urgent business until after I got in touch with Ray Kimber. DiAural is the real deal, in this reporter's opinion. License inquiries can be made by fax at 801-627-6980.

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