IMN (Idaho Music Notes): What is an AcoustiCoil?
DN (Don Novy): An insert to the bore designed for woodwind and brass instruments to improve their response acoustically.
IMN: It goes inside the instruments?
DN: Yes
IMN: What does it look like?
DN: It's coiled in the shape of a compressible sleeve, made of tough, resilient industrial polyester. This unique design permits a "spring fit" and adaptability to the various bore sizes of instruments.
IMN: Won't something like that "blow-through" an instrument?
DN: No. Actually, contrary to what one would think from the many references to the air "stream" in wind and brass instruments, an instrument's air column moves through it quiet gradually. You can observe this by exhaing smoke through an instrument as you play; it exists several seconds later.
IMN: So there's not much "force" to the air inside an instrument?
DN: No, not in the lateral sense. As soon as sound is produced, the air column is vibrating rapidly, true, but like a solid mass from the point of initial impulse (mouthpiece) to the point of no pressure (bell or tone hole). Also, as the speed of the air column's vibration determines pitch, it divides into long and short longitudinal "standing" waves (alternate regions of high impulse pressure/non-pressure). This rapidly vibrating air column, then, slowly displaces itself.
IMN: Why improve response on an instrument?
DN: WIth improved response, instruments play with better focus, projections, and resonance. It's the difference between "professional" and "student" line instruments. The more expensive professional level instruments invariably play with better response than less costly student models. Difficult articulation, dynamics, intonation, and range problems are elssened and endurance is improved with better response. The player doesn't have to work as hard!
IMN: How does the AcoustiCoil improve response?
DN: By "constructive interference"....That is, this is what happens to waves on water when they intersect each other...they're taller at that point and therefore their interference is said to be "constructive". Similiarly, the AcoustiCoil's patented edge technologically increases the strength of the standing waves in instruments. It's the same thing as an "impedance loop" in electronics, which matches impedance and produces more power.
IMN: What's that....impedance, that is?
DN: In electronics (and acoustics), impedance is the ratio of input to resistance. And...when you transfer this equation to making music with a wind or brass instrument, the player is obviously the input and the instrument the resistance. Now, if we match impedance (add input and resistance simultaneously), as the AcoustiCoil does, up to a certain point the player doesn't have to exert as much input to play his instrument.
IMN: You mean, it makes it easier?
DN: Yes!
IMN: How did you ever come up with this?
DN: Back in 1973 I discovered a way to make interference constructive to the standing wave in horns. I had often wondered why one particular valve combination on my trumpet seemed play better before it was "fixed" with new felt piston pads. Contrary to what every repairman had ever told me, my experience was always that the A-flat (second and third valves down) appeared to lose some of its presence each time I had the valves repaired with new felts. This is routinely done to re-align piston and valve casing ports when the pads become worn, to "return the horn to playing like new.". However, in the case of my A-flat, it played better "like, old!"
   Intrigued, then, by this disparity between a common repair practice and my "old A-flat", I set about to research the whole field of interference in physics and acoustics.
IMN: Did your research then reveal new information?
DN: Actually, it revealed old information! A 1953 research report from the Defense Research Institute at the University of Texas proved years earlier that interference caused by an abrupt change in a cylindrical acoustical system (like that of a trumpet) can produce a matched impedance (added in-put from mismatched ports, as in my "old A-flat!). Knowing this, I then established the "AAIIRR" power custom repair for better response on piston-valved brasswind instruments; the AAIIRR logo derived from Acoustically Adjusted Interference for Improved Reponse through Research, patented in 1976.
IMN: How did the AcoustiCoil come about then?
DN: A friend who is both a trombonist and a doctor of physics suggested that since all wind and brass instruments work the same acoustically, I could improve his instrument by simply designing an insert to the bore containing the same constructive interference as the AAIIRR formula...I did, and it did!
   Subsequent requests from family, friends, and associates to see if I could improve the response on their instruments have now resulted in twenty-one models of AcoustCoil; one for almost every type of brass or wind instrument.
IMN: What has been the response from players to AcoustiCoil?
DN: Most players find it hard to believe at first...but then, afet actually using it, become ardent believers! Surprised, they've said "it's amazing", "I like it", and "How did you do that?" far more than "noticed no difference" or "not for my instrument."
IMN: Are there, then, negatives to the AcoustiCoil?
DN: Positive responses by far outweight the few negatives; the AcoustiCoil and installation area within the instrument have to be kept clean to function well..However, that should go without saying on all brass and wind instruments! Also, not all instruments or players necessarily need response improvement...Some highly competent players view any change as distruptive to their technique...And, the degree to which an AcoustiCoil improves an instrument is of course dependant on how responsive it is to start with. Some instruments respond very well. Overall, however, I've found that most instruments and players can use, and/or welcome the AcoustiCoil's help...For those who don't, it comes with a money-back guarantee...and, in the past year we've had less than a 2% return. This is very gratifying to me in that it shows that the AcoustiCoil does indeed help players 98% of the time!
Packaged as a complete "do-it-yourself" kit including illustrated instructions and a retriever/gauge tool fo adjusting the coil's inner reflective edges, AcoustiCoils retail for $35.00 and may be ordered direct. For a free brouchure and additional information, click here

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Image Courtesy of the AcoustiCoils website. This image was not included with the original article.