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According to John Kreskovsky, first order series crossovers with a zeta of 0.5 are quasi second order filters: http://www.geocities.com/kreskovs/Series-1.htmlAre the VMPS speakers with a series crossover really QSO ("quasi second order")?I am asking this question because I made a computer simulation of the crossover (woofer to mid panel) using the capacitance and inductance found in my single wire QSO 626R. I have found that the calculated zeta is 1.35 using the formula zeta = sq ...
"Sawtooth" Chris Regan, my patent attorney, has advised me to release no more technical details about the invention until the patent is granted in about 18 months.
Off axis problems have been solved by the new technology. I am reconfiguring my measurement bed for wider range use and the results should be up shortly. You will see improvements in linearity from the "new tech" as well.
BrunoYou dear sweet naive man..... I have established the only authorized VMPS pool for the date the specs appear. You can take either odd or even days, $100 per bet, or you can go as low as $1 per square for the actual calendar date the specs appear. All profits go to the tax-exempt 503 charity approved by the pool betters, but the charity must foward at least 31% of their revenues toward the actual charitable work (thus excluding the Shriners). To all VMPS fans: You are hereby deputized ...
Having received the go-ahead from "Sawtooth" Chris Regan, my patent attorney, I invite you to join me on a lengthy description and account of the US patent filed 10/13/05, with yours truly inventor and applicant, originally entitled:"Planar Loudspeaker with Constant Directivity Full Range" Background of the Invention:It's Jan 10, 2002. James Bongiorno and I sit at his favorite Italian restaurant in LV basking in the glow of the RM 40's winning the "Best of CES for High End Audio". He doodles on a cocktail napkin and reveals the rough shape of a speaker enclosure. "Build this", he rasps, "and you will win again!" The cabinet is that which I will spend the next year turning into the RM/X speaker system, and James is proven a true prophet in 2003 as the VMPS Alexis Park booth takes the big prize a second time.Course you know this story since I've only told it a dozen times here and everywhere on line.Matters did not conclude that evening with but a single napkin, there followed another.This sketch was of a tall, narrow curved baffle covered with interlocking triangular planar mid/tweeters, placed apex to base. There was also a unique arrangement of small woofers which would produce a hemispherical launch pattern for the bass. "Build this", James intoned," and you will win again in 2004." Well again as you already know, that didn't happen. After the second win the Tech TV judge told me in confidence we would never threepeat regardless of what I came up with. Our 2004 entrant, the RM 30, finished 8th in the competition that year.Still, the idea of a triangular planar driver intrigued me and would not leave my mind. I went looking for a manufacturer and a partner. In June 2003 we pitched Mark Shifter on the idea of Constant Directivity in loudspeakers generally and the trianular planar magnetic panel inparticular, and while Mark was most enthusiastic, further meetings did not lead to the hoped-for collaboration. John Casler reported extensively on the initial contact on this very board. The curious can search the archives from the summer of 2003 and find the threads.The triangle is a great shape for a driver (and a cabinet for that matter, but for different reasons) because it narrows to zero width. If it is made slender and long enough it will maintain excellent directivity with frequency over the range it covers--I was hoping for 300Hz to 20 kHz. It would have to be a few inches wide at the base so that the panel could start at that width. It is the nature of planar panels that their excursion is essentially zero at the edges and maximum in the center of the diaphragmmuch like a plucked bowstring. There isn't any pistonic motion so paradigms that strive in that direction don't work with planars. As it turns out, the ideal shape for a planar from the standpoint of linearity(flat amplitude response) is a large square, say 10x10", which is great for low distortion and LF extension but terrible for directivity. I would not arrive at constant directivity with a driver which became rough and beamy at 900Hz.Other shapes than the triangle would approximate the requirements for CD (I'll use this abbreviation for Constant Directivity henceforth, since it's the industry standard). A diamond, particularly a double diamond, would do well; back to back double-D's (like the Dolby logo) and other wasp-waisted forms which begin wide and narrow to about 2/3" get the job done too.I found a prototyper and made sample panels of various shapes and configurations. Things did not go well. It turns out asymmetrical traces on a rectangular diaphragm do not produce smooth FR or low distortion, and I was getting tons of both problems. 6% THD was typical, and linearity was poor below 2 kHz. The undriven portions of the diaphragm undulated and flapped antiphase to the driven part where the triangularly shaped traces were etched into into the film (I used PEN). It would do no good to have evenly dispersed sound no one would want to listen due because of roughness and high THD.Over two years had gone by and I had nothing to show for them except rejects. (end of Part the First. In Part Deux, I commit Ritual Harikiri in atonement for my failings).
