An Interview With AcoustiCoil's 
Inventor, Don Novy

IMN (Idaho Music Notes): What is an AcoustiCoil?

DN (Don Novy): An insert to the bore designed for brass and woodwind instruments to improve their response acoustically. 

IMN: It goes inside the instrument?

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 quite gradually. You can observe this by exhaling smoke through an instrument as you play; it exits several seconds later.

IMN: So there's not much force to the air inside an instrument? 

DN: No, not in a 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, projection and resonance. It's the difference between "professional" and "student" line instruments. The more expensive professional level instruments invariably play with better response than the less costly student models. Difficult articulation, dynamics, articulations, intonation and range problems are lessened 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." Similarly, the AcoustiCoil's patented edge technology 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/her 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 trumpets. I had often wondered why one particular valve combination on my instrument seemed to play better before it was "fixed" with new felt piston pads. Contrary to what every repairman had told me about this situation, my experience was that A-flat (second and third valves down) appeared to lose some of its presence each time I hadthe valves repaired with new felts. This is routinely done to re-align piston and valve casing ports when 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 report from the Defense Research Insitute at the University of Texas proved years earlier that interference caused by an abrupt change in a cyindrical acoustical system (like that of a trumpet) can produce a matched impedance (added input from mis-matched ports, as in my "old A-flat")! Knowing this, I then established the "AAIIRR" - Power custom repair for better response on piston-valved brass/wind instruments; the logo derived from Acoustically Adjusted Interference for Improved Response Repair, patented in 1976. 

IMN: How did the AcoustiCoil come about then?

DN: A friend who is both a trombonist and 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 AAIRR formula.... I did, and it did! Subsequent requests from friends, family and associates to see if could improve the response on their instruments have now resulted in 20 models of AcoustiCoil: one for almost every type of brass or wind instrument. 

IMN: What has been the response from players to the Acousticoil?

DN: Most players find it hard to believe at first... but then, after actually trying one, 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 out-weigh the few negatives... The AcoustiCoil and installation area within the instrument must be kept clean to function well..... However, that should go without saying with all brass and wind instruments! Also, not all instruments or players necessarily need response improved... some highly competent players view any change as disruptive to their technique.... and, the degree to which an AcousticCoil improves an instrument is of course dependent on how reponsive it is to start with. Some insruments 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 30 day money-back guarantee.... during the past seven years that they've been available, we've had only less than 2% returned, which is very gratifying to me, as it shows that the AcoustiCoil repair does indeed help players 98% of the time!

From Ted Hadley, Editor, Idaho Music Notes: I ordered AcoustiCoils for all the instruments in my family. I'm still experimenting with mine (for lack of time to really give it a fair shot), but my flute playing daughter has really used hers. She reports improved upper note response and better focused intonation. She's won the State Solo Gold Medal twice! If you are at all curious, you ought to take advantage of Don's money back guarantee and give it a try!

Page 28, Idaho Music Notes, Fall 1994