From: Steve
To: info@diaural.com
Sent: Tuesday, October 03, 2000
Subject: DiAural got to have it!

Sadly the only dealers that offer speakers with your crossover, ALL except 1 are ridiculously expensive and the 1 that isn't has poor linearity of response of their design. What I need is a (brand name deleted) Studio Monitor optimize for your x-over. They have great linearity, great value, and I just bet with your x- over they would be absolutely superb.

How am I going to survive waiting for this great technology? Not until 2001 are kits available HOW CRUEL! Please tell me there is some way for this radio station to get some good speakers with these x- overs! You got me scanning the old EDN magazines looking for circuits that reflect and selectively pass bands of frequencies. I just got to hear these things!

What about using your circuit as an active crossover and bi-amping, does that ruin the transducer interaction benefits you talk about?

Steve

From: info@diaural.com
To: Steve
Sent: Wednesday, October 04, 2000
Subject: DiAural

Dear Steve,
Thank you for you interest and our shared excitement in DiAural. You should contact (brand name deleted) and inquire as to whether they have any plans to use DiAural in any of their products. Our circuit works best with the transducer interaction. It is pretty much required. Please keep your eyes and ears open for more news about DiAural.

Best regards,

DiAural

From: Steve
To: info@diaural.com
Sent: Wednesday, October 04, 2000
Subject: Re: DiAural

After having done some additional research I am quite embarrassed I was so excited about this x-over. Based on the schematic from the European Patent office freely available on the net this x-over is nothing more than a series x-over that appeared in textbooks decades ago!! Good luck trying to defend a patent in court (I would be really disappointed in US patent office if they do grant a patent on this). My enthusiasm was based on some misguided press I read. These publications really have egg on their face now. (not the first time!). The audiophile newsgroups in the know have really ripped Kimber for this one! Proper active pass over with biamping, triamping would be far superior to this circuit.

Steve

From: info@diaural.com
To: Steve
Sent: Wednesday, October 04, 2000
Subject: DiAural Circuit

Dear Steve,

The series crossover that was described in textbooks, including Olson and others was based on the use of a capacitor and inductor. Using the resistor as the primary element (instead of a capacitor) makes the circuit a very different animal, and we did, in fact, get a patent on it, US patent 6,115,475. The foreign patents are pending but we expect to get those also. The only circuit that even came close was a patent by Sonus Faber (Italy).

We did extensive patent searches and very extensive published material searches, we don't know of any reference to the circuit, all of them use capacitors as the primary element. I am including a short list of reviewed material. In addition we have a complete set of AES Journals, The Journal of the Acoustical Society, The Bell Labs Record and The Bell Labs Technical Journal, these were also reviewed. In short we performed significant due diligence to assure that we were not patenting prior known art. Since you state that the circuit had appeared in "textbooks decades ago" I would sincerely appreciate you providing me the name of any one of them!!

Sheesh, it's not like being in the cable business hasn't gotten me "egged and ripped" before. (And I still have my sense of humor too.)

Kind regards,

Ray Kimber

BUILDING SPEAKER SYSTEMS McComb, Gordon
AUDIO TECHNOLOGY SYSTEMS Cameron, Derek
AUDIO ENGINEERING HANDBOOK Benson, K. Blair
HI-FI LOUDSPEAKERS AND ENCLOSURES Cohen, Abraham B.
THE SCIENCE OF SOUND Rossing, Thomas
RADIO AND ELECTRONICS Morgan, Alfred
AUDIO ELECTRONICS Hood, John Linsley
RESISTIVE CIRCUITS Babb, Daniel S.
SIMPLIFIED PRACTICAL FILTER DESIGN Gottlieb, Irving M.
PRACTICAL ELECTROACOUSTICS Rettingger, Michael
HIGH PERFORMANCE LOUDSPEAKERS Colloms, Martin
LOUDSPEAKER AND HEADPHONE HANDBOOK Borwick, John
DESIGNING, BUILDING, AND TESTING YOUR OWN SPEAKER SYSTEM Weems, David B.
HOW TO BUILD SPEAKER ENCLOSURES Badmaieff, Alexis
THE COMPLETE GUIDE TO HIGH FIDELITY Clifford, Martin
THE COMPLETE HANDBOOK OF PUBLIC ADDRESS SOUND SYSTEMS Everest, Alton BASIC
AUDIO COURSE Hoefler, Donald Carl
THE SOUND OF HIGH FIDELITY Jordan, Robert Oaks
THE RECORDING AND REPRODUCTION OF SOUND Read, Oliver
SWOOPE''S LESSONS IN PRACTICAL ELEC. Hausmann, Erich
THE GRAMOPHONE HANDBOOK Wilson, Percy
RADIOTRON DESIGNER''S HANDBOOK Langford-Smith, F.
AUDIO SYSTEMS Herrick, Clyde N.
GREAT SOUND STEREO SPEAKER MANUAL Weems, David B. 21
HI-FI STEREO SPEAKER CABINETS YOU CAN BUILD Robin, Christopher
AUDIO CYCLOPEDIA Tremaine, Howard M.
ACOUSTICAL ENGINEERING Olson, Harry F.
AMPLIFIER HANDBOOK 1940 1941 Asch, Moe
THE RADIO-ELECTRIC MASTER United Catalog Publishers
ACTIVE AND PASSIVE FILTERS AS LOUDSPEAKER CROSSOVER NETWORKS Ashley, J. Robert
THE ART OF ELECTRONICS Horowitz, Paul''
TEACH YOURSELF ELECTRICITY AND ELEC. Gibilisco, Stan
THE LOUDSPEAKER DESIGN COOKBOOK Dickason, Vance
REPAIRING HOME AUDIO SYSTEMS Ecklund, E. Eugene
LOUDSPEAKER HANDBOOK Eargle, John M.
THE PRACTICAL HI-FI HANDBOOK King, Gordon J.
SOUND AND RECORDING AN INTRODUCTION Rumsey, Francis MUSIC ENGINEERING Brice, Richard
HIGH FIDELITY TECHNIQUES Newitt, John H.
HANDBOOK FOR SOUND ENGINEERS Ballou, Glen
FROM MICROPHONE TO EAR Slot, G. R-C/R-L
TIME CONSTANT Schure, Alexander
STUDIO MONITORING DESIGN Newell, Philip Richard
THE CAPACITOR HANDBOOK Kaiser, Cletus J.
DIVIDING NETWORKS FOR LOUDSPEAKER SYSTEMS Hilliard, John K.

From: Steve
To: info@diaural.com
Sent: Wednesday, October 04, 2000
Subject: DiAural

Thank you for your courteous , classy, and factual reply. I had not checked the impressive list of sources you gave . I was quoting others that I found on deja news search. Do you have any double blind listening tests that you can share results on yet? Also I have consulted a source that has many BIY plans on his site. He says that it is well known that a good x-over will compensate for the "doppler distortion" from the mics. Is there anything then new about your claim with regard to your x-over? There was specific mentioning of the Sonus Faber x-over in comparison to yours and YES they said there was a slight difference. There were MANY folks who all claimed that your x-over was a old design. I think a statement from yourself similar to the below posted to these audio groups would be quite useful. You have done quite a bit of homework in support of the claim that this circuit is different. The resistor in the circuit resulted in controversy. Wouldn't the resistor in parallel with the woofer cause the tweeter to be subjected to unsafe LF content because of the woofer voice coil feeding back to the tweeter?

Thanks again for answering my premature flame.

Steve

From: Robert
To:info@diaural.com
Sent: Thursday, October 12, 2000
Subject: Information

What makes this crossover so uniqe over other crossovers. Does it use caps and coils on a circuit board or is it something new, If it is new what does it look like I see no example on your web site.

From: info@diaural.com
To: Robert Sent: Monday, October 16, 2000
Subject: DiAural

Dear Robert,
Thank you for your interest in DiAural. The uniqueness of the circuit is in the elimination of capacitors as a primary element in a series configuration. As with other crossover designs it is possible to use a circuit board. This new circuit is not something that can be easily added or retrofitted to an existing speaker, it would need to be designed into the speaker system by the speaker designer. The new circuit is also not applicable to all speaker systems, in way of example let me use an analogy. Suppose there are cars manufactured with carburetors. At some point the car maker might make a decision to use fuel injection instead of carburetion. In order to fully exploit fuel injection there might be many small and large changes to the car; timing, location of fuel pump, intake manifold, geometry of valves and so on. As you can see it might not be possible for a customer to retrofit his car with the new fuel injection, or at least not economically or with maximum exploitation of the fuel injection technology. There would also be some models with engines that work better with carburetion. The DiAural circuit has been granted U.S. Patent # 6,115,475 with other U.S. and foreign patents pending.

Best regards,
DiAural

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