A PORTABLE PVC "BANSHEE" WIND FLUTE Art Hunkins abhunkin@uncg.edu www.arthunkins.com 9/23/2016 with Addendum for A PERFORMABLE PVC WIND FLUTE (2018) INTRODUCTION I've always been intrigued by natural sounds and instruments. My digital music often includes the recording or sampling of water, birds, crickets and bells.[1] I've synthesized many clangorous sounds, and have also worked extensively with acoustic chimes - especially those intended for the outdoors, and activated by the wind.[2] My fascination with wind chimes led me to other wind-activated instruments and installations, including bamboo Aeolian flutes/organs. Two online articles dedicated to these novel instruments directly suggested the current project.[3] A note about terminology: "flute" refers here to an entire instrument; "pipe" refers to an assembly of several PVC components that produces a single pitch. Multiple pipes (each a pipe assembly), plus a supporting structure, comprise a flute. Short segments of "pipe tubing" are the main component of a pipe assembly. My goals for this project were: 1) The materials should be inexpensive and available locally (my target: Lowe's - which carries all items below except the optional flag). Complete PVC parts for a basic 8-pipe flute [detailed below] come to a bit more than $41 plus tax. The optional thin-wall "fine-tune" PVC can cost an additional $3 for each diameter of pipe [1" or 3/4"]). 2) The flute should withstand the weather for considerable periods of time. 3) It should be portable. 4) It should be self-standing, including in considerable wind. 5) Pipes should be readily exchangeable, and reasonably tuneable. 6) The flute should be modestly performable, i.e., pipes can be individually oriented toward (or away from) the wind and their amplitudes varied in real time. THE BASE The most costly part of the flute is the Adams (Manufacturing) Umbrella Base ($13 at Lowe's)[4]. It is a seasonal item that disappears from Lowes' shelves in fall and winter, but is always available online. By itself, it can support the instrument on any flat surface in little or no wind. With any significant wind at all, the base must be at least half-filled with water or sand. The "port hole" is on the top of the base so the base won't leak; its stopper can be removed with a slotted screwdriver. The base is comprised of three pieces: the base itself, the holder for the pole (umbrella) and the pole tightener. The components need to be separated prior to fitting the pole. The base itself is detached for portability. THE POLE Note: all PVC is (thick) SCH40 unless specified otherwise. Several configurations of vertical pole are possible: 1) A single 5' pole of 1" diameter PVC tubing. This pole accomodates up to 8 or so pipes. 2) A lower 3' pole of 1" diameter PVC with an upper 2' pole of the same diameter. The upper pole accommodates up to 6 pipes (the lower pole has none). The poles are joined with a 1" slip coupling. (No cement is required when attaching these components, even the pipe assemblies.) This arrangement separates the pole into two more portable segments. A terminating 1" slip cap is optional. 3) The same as #2 only with an upper 20" pole of 3/4" PVC that accommodates up to six 3/4" pipes. The poles are attached with a 1" x 3/4" slip x thread adapter and a 3/4" thread x slip adapter. A terminal 3/4" slip cap is optional. 4) A combination of #2 and #3 above: a bottom 3' pole, a middle 2' (1" diameter) pole, and a top 20" long, 3/4" diameter section. All 3 couplings/adapters are required, but only the 3/4" optional cap. Here the capacity is 12 pipes. The bottom (or only) pole requires special preparation: wrap 2" duck tape continually around the lowest 2" of the pole until the pole fits loosely (not tightly) into the bottom of the pole holder. (I also place a circular cut of cellulose sponge into the bottom of the holder; this further anchors the pole.) Then screw the pole tightener completely and securely into the pole holder. The pole should now be well (but not permanently) lodged in its holder; for portability it and holder may be treated as a single unit. Desired lengths of PVC can be cut with a miter saw, miter box, or any tool (such as hacksaw and vise) that produces a clean, right-angle cut. THE FLUTES Each pipe assembly consists of four pieces of PVC: a snap Tee, a thread x slip adapter, a short piece of PVC tubing, and a slip cap. Pipes can be either 3/4" or 1" in diameter. Cut both types to the following lengths: 2 1/2", 2 3/4", 3", 3 1/2" and 4". For each diameter, pipes will vary *approximately* 1/2 tone one to the next (e.g., B to C). Depending on the diameter of the pipe and of the vertical pole, three assembly configurations are possible: For 1" pole, 1" pipe: 1" x 3/4" snap Tee, 3/4" x 1" thread x slip adapter, 1" diameter PVC tubing, 1" slip cap. For 1" pole, 3/4" pipe: 1" x 3/4" snap Tee, 3/4" thread x slip adapter, 3/4" diameter PVC, 3/4" slip cap. For 3/4" pole, 3/4" pipe: 3/4" snap Tee, 3/4" thread x slip adapter, 3/4" diameter PVC, 3/4" slip cap. For each pipe, cut the above lengths of 3/4" and/or 1" PVC that you intend to use. Now comes the tricky and potentially dangerous part. I recommend it be accomplished with hand tools: a fine-toothed saw, flat or square file, and a vise or similar. (The operation would be much simpler with a table saw, but *this is hazardous* due to the possibility of kickback.) With two cuts, create a lengthwise slit in each segment of PVC tubing, that measures 1/4" wide *across the opening*. If possible, cut toward the inner side wall to produce a 45-55 degree angle on either edge of the opening. While doing so, *do not enlarge the opening of the slit*. If such a cut is not possible, complete the cut by filing to the correct angle.[5] The width of the slit is a crucial factor: it can be anywhere from 1/8 to 1/4 inch across, but *not more than 1/4"*. (Pitch is unstable beyond 1/4".) 1/8" slits produce a pitch 1 1/2 tones lower than do 1/4" (e.g., C down to A). Those between 1/4" and 1/8" in width will produce intermediate pitches. Once the lengths of PVC are prepared, place a strip of 3/4" vinyl electrical tape around each end, but *not* including the slit. Fit one end into the adapter, the other to the cap. If either end is loose, apply another inch (or less) of tape at the approximate midpoint of the initial layer. The connections should be finger-tight, yet the parts easy enough to insert and move. Pitch and amplitude of the pipes vary according to these factors: 1) Narrower slits give lower pitch; their pitch is more focused but amplitude is softer, and they require precise placement into the wind to sound at all. Wider slits, up to the recommended limit of 1/4", have the opposite effect. 2) Shorter PVC segments produce lower pitches than longer ones. 3) 1" diameter PVC produces a pitch one tone lower than 3/4" (e.g., B down to A). 4) 1" diameter PVC sounds louder than 3/4". 5) Higher pitches are somewhat louder than lower ones. Given the above variables, I recommend the following for best results: 1) Use 1" PVC for most of your pipes; 2) Use 3/4" PVC only for pitches *above* the 1" PVC range (i.e., above C5); 3) Use narrower slits - with 1" PVC - for pitches *below* the normal 1" range (i.e, below A4 - "tuning A"). A BASIC INSTRUMENT My basic 8-pipe, single-pole flute implements the above recommendations. It also spans the entire useful pitch range - a perfect fifth from G4 to D5 (middle C = C4). My lowest pitch, G4, progresses in approximate half-tones up to D5 - with pipes in inverse placement on the pole. From low to high pitch (high to low pole position), the pipes are: [the first 6 are 1" in diameter] 1) 3" in length, with narrow 1/8" slit (G4) 2) 3 1/2", with narrow 1/8" slit 3) 2 3/4", normal (1/4") slit (A4) 4) 3", normal slit 5) 3 1/2", normal slit 6) 4", normal slit (C5) [the last 2 are 3/4" in diameter] 7) 3", normal slit 8) 3 1/2", normal slit (D5) FLUTE "PERFORMANCE" An important caveat: You cannot in any sense "perform" this instrument except in a stiff, steady wind. Gusts will only elicit intermittent whispers. Pipes respond to the wind when facing it, with slits either directly up (recommended) or down and slightly turned into the wind. Pivot individual pipes on the pole, in or out of the wind, for it to play or not. (Turn the pipe from the cap and hold your other hand on the center pole, away from the pipes; otherwise you can pinch your hand.) For somewhat more control of volume in a steady wind stream, you can slowly turn an individual pipe on its axis (again holding the cap), more into the wind or not. For the greatest precision in "live performance", you may want to PVC-cement the cap to the pipe, so it will not slip as you rotate. (Don't tape the cap end of the pipe if you use cement!) Standing behind the instrument (and facing the wind) will keep your body from impeding the wind flow and minimizing the sound. "PRECISE" TUNING Though the total pitch range of the flute is limited, it is possible to tune its pipes to some degree. 1) Note that pitch (as well as amplitude) changes as you rotate the slit into the wind. With 1/4" slit on a 1" diameter pipe, pitch can vary as much as a whole tone as you gradually turn the pipe. 2) You can tune the pipes reasonably well with short segments of *thin-walled* 200PSI PRSR PVC that match your pipe's diameter. Cut multiple segments of 1/8", 1/4", 3/8", 1/2" and 5/8" lengths for the diameter(s) of tubing you are using. Then, with a pair of snips, remove 1/4 of the circumference of each segment. To adjust pitch downward (upward is not possible), snap an appropriate length of thin-wall onto either end of the exposed pipe, over the slit. The longer the thin-wall segment, the more the pitch lowers. Again, pitch is adjustable by a tone or more. (It's also possible to use a piece of thin-wall at *both* ends; the pitch lowering is additive.) WHICH WAY IS THE WIND BLOWING? You may find it difficult to determine precisely which way the wind is blowing. Wind direction can change frequently, and greatly affect how (and whether) the flute responds. A small flag inserted into the top cap can help. I used an 8" x 5 1/2" hand-waving flag ordered online, rather than the more commonly available 6" x 4" size. (I was afraid that a smaller flag wouldn't flutter sufficiently; I now believe it should work fine.) Be sure to obtain a flag that *slips onto its pole*, rather than one that is stapled to it. (You want the type where flag and flagpole are packaged separately - not when they are already attached.) Drill a hole for the pole vertically in the cap (it's important for the hole to be precisely vertical). Suggestion: start with a slightly smaller bit and increase the size until the pole barely fits. If the fit is loose, you'll need to glue the pole to the cap (I used superglue). ALTERNATIVES - part sources, larger pipe diameters? Home Depot, another local source for PVC, unfortunately carries only about half of the required parts. The real show-stopper is their lack of snap Tees. Home Depot also does not stock an appropriate umbrella base. The Adams Umbrella Base ia additionally available from a number of online sources. The Semco (Plastic Company) Umbrella Base is an identical (or near-identical) product that sells for a comparable price. I'm unaware of any other bases that come close either in features or price to meeting the requirements of this project. It's important to note that the Adams base will accommodate *only* a 1" diameter pole. (1 1/4" is barely too large.) As a result, our snap Tees must be either 1" or 3/4" (the latter for an upper 3/4" diameter pole). Probably the most fruitful alternative feature here would be to extend our total pitch range higher with 1 1/4" diameter pipes. These pipes should also produce sbstantial volume. (1 1/4" pipes are the largest diameter practical on a 1" pole.) They would require a 1" (x 1") snap Tee, however, which Lowe's does not carry. Lowe's *does* offer the other parts for a 1 1/4" pipe assembly: 1" x 1 1/4" thread x slip adapter, 1 1/4" diameter PVC tubing (in a 5-foot length), and 1 1/4" slip cap. Here is where FlexPVC.com comes to the rescue. FlexPVC carries absolutely everything PVC you could ever want - including the 1" snap Tee (FPT - Female Pipe Thread) we'd like. I highly recommend this company for all PVC accessories. (FlexPVC's only downside is that shipping is a bit high, though the company compensates by generally lower unit pricing. Turnaround is fast.) When buying from FlexPVC, you can save a little money by making the following Tee substitutions (doing so will eliminate the thread x slip adapters in these cases): For 1" pole, 1" pipe: 1" snap Tee Spears (463-010S), in place of 1" x 3/4" snap Tee (FTP) and 3/4" x 1" thread x slip adapter. For 3/4" pole, 3/4" pipe: 3/4" snap Tee Spears (463-007S), in place of 3/4" snap Tee (FTP) and 3/4" thread x slip adapter. Note: Numbers/designations in parentheses are FlexPVC identifiers, and the "Spears" labeling is essential. In addition, these Tees are of the "pressure," rather than "slide" variety. (FlexPVC offers lots of choices! Thankfully, their website is well organized and informative.) CONCLUSION A final word of advice: It takes *at least* a steady 15+ mph wind to produce any sound whatever from this flute. To date, the instrument has only been successfully tested at the seashore. It is no coincidence that all projects described in the referenced articles are located on a beach or in the mountains - in either case, in a large, open, wind-swept area. So, "May your flag fly high, and your banshees cry!" [1] A complete list of my recent acoustic and electronic works is @ www.arthunkins.com . Brief descriptions are included, as well as demo performances of selected compositions. [2] My two articles relating to wind chimes are found at www.arthunkins.com/articlesother.htm . One is entitled "Making a Portable Windchime Rack"; the other, "Varying the Pitch of Tubular Aluminum Windchimes." The latter incorporates one of the fine-tuning methods described here. Both articles are also posted to the Yahoo WindChimeForum group. [3] Uli Wahl's "The Bamboo Aeolian Organ," http://www.windmusik.com/html/bamborgl.htm , and Bruno Tondellier's "Aeolian Flute/Organ," http://www.ventcourtois.com/flute_plastique/pg_flute1.htm . Both articles are treasure troves of inspiration and creativity. (The latter is in French only and is not auto-translatable.) Wahl's article gives all sorts of cultural and historical information, while Tondellier's is a detailed guide to construction. Both are filled with marvelous links and additional relevant material. My project is deeply indebted to Tondellier's flute/organ. (You can see and hear his "banshee" flute/organ @ http://www.ventcourtois.com/flute_plastique/pg_flute2.htm .) [4] An alternative "base" option is available for a sandy or loose/garden soil environment: various models of beach umbrella *anchors* or stakes. Highly recommended is the Mainstays Sandgrabber Beach Umbrella Anchor from Walmart ($10). It is made of steel and purports to withstand 30 mph winds. One reviewer suggests that it works best when you dig a hole first, then screw it into the sand or earth. Obviously, this option is not readily portable and is only appropriate for semi-permanent installation. (Photos are included in the PerformanceFlutePhotos.zip archive.) Though the anchor requires considerable effort to install, it is simple to remove. [5] This procedure is well illustrated by Tondellier ( http://www.ventcourtois.com/flute_plastique/pg_flute1.htm ). Note that unless you can manage to cut the PVC at an angle, you'll be in for a great deal of filing. (The recommended angle is also illustrated by the WindFlute9 photo.) THE PHOTOS (WindFlutePhotos.zip) WindFlute1: Basic 8-pipe, single-pole flute complete with optional flag. Slits slightly tilted into wind. Bottom 2 pipes are 3/4". WindFlute2: Detail of top 6 pipes of basic flute. Slits face forward, showing that the top 2 pipes have narrow (1/8") slits. Three of the pipes have small pieces of thin-wall PVC for fine-tuning. WindFlute3: Two-section pole with 3/4" diameter upper section. All pipes 3/4" diameter. No flag, optional top cap. WindFlute4: Detail of WindFlute3, with slits tilted into wind. Note the larger pieces of thin-wall PVC on all pipes, and two-piece adapter joining the poles. WindFlute5: WindFlute3 2-section pole disassembled. Note bottom pole firmly imbedded in holder and tightener, for easy insertion into and removal from base. WindFlute6: Base disassembled, and bottom pole. Pole tightener screws onto pole holder. Bottom of pole wrapped in duck tape for tight fit in bottom of holder. Note position of water/sand port on top of base, and cap (removeable with slotted screwdriver). WindFlute7: Three varieties of pipe: at top, 3/4" pipe for 3/4" pole; middle, 3/4" pipe for 1" pole, narrow slit; bottom, 1" pipe for 1" pole (with detail of snap Tee). WindFlute8: The 3 pipes of WindFlute7 disassembled. Note electrical tape on each end of pipe tubing. Flag slipped onto flagpole (not stapled); flagpole drilled through cap (to bottom of cap here, since pole is glued in). WindFlute9: Detail of 3 pipe tubes showing how slits are cut (and filed). Two 1" pipes flank a 3/4" pipe. The left pipe has a narrow (1/8") slit, the others, 1/4". Addendum for A PERFORMABLE PVC WIND FLUTE (2018) The Performable PVC Wind Flute is a variant of the above Portable PVC "Banshee" Wind Flute, in which tube pitch can be interactively changed during performance. It is identical in construction to the "Banshee" flute except for the flutes themselves; these substitute 1" *thin-walled* (200PSI) PVC and 3/4" SCH40 PVC "sliders" for the short piece of (SCH40) tubing and slip cap. (Adapters are of the 3/4" x 1" thread x slip variety.) The instrument requires only the single 5' pole of 1" diameter SCH40 PVC tubing, and consists of a maximum of 4 flutes. (The available pitch range is only modestly more than an octave; the flutes play chords, and more than a 4-note chord moving within this range is likely impractical.) The Performable Flute is somewhat more involved and expensive to construct. The 10' length (shortest available) of 200PSI thin-walled PVC tubing for these flutes costs under $3. To *slit* the tubes, however, requires a *fixed router with a 1/8" straight bit*. In addition, the sliders that determine pitch need custom-fit felt pads on one end to seal the inner flute chamber[1] and to keep the sliders from slipping. To customize the felt pads I recommend the Scotch 2-Felt Pads package ($5) from Lowe's (alternative: Waxman $3 2-Felt Blankets package from Walmart). The 1/8" bit, unfortunately, is exorbitantly priced at Lowe's ($18); I'd try on-line or at Harbor Freight, where an all-metal 1/8" bit is part of their Solid Brass Router Inlay Kit ($9). In any case, be sure to get an all-metal bit; one that is part plastic will break. (The length of the actual bit is relatively unimportant.) THE FLUTES: Tubes I suggest two 12 1/2" tubes and two 13" tubes. The 13" tubes will be pitched 1/2 to a full step lower than the shorter ones, and will be more responsive to lower pitches. (Tubes longer or shorter than these lengths offer no advantage; they do not speak as well over a wide range of pitches.) On each tube a 1/8" slit needs to be cut by the router. The cut starts 1" from tube end, and runs for 2" (stopping 3" from the end). The slit needs to be at as sharp an angle as possible, without its top slicing into the inside tube wall. The *acute* cut must face into the wind for the flute to sound. (Unlike the "banshee" flute there is no sound when the opposite edge fronts the wind.) Here, the angle of slit to wind direction is crucial for sound to occur. Keep the cut in a straight line, and stop the cut by turning off the motor rather than lifting the tube from the cutter. Clean the cut with a utility knife and a fingernail file (optionally assisted by fine sandpaper). Smooth the cut as much as feasible while keeping the leading edge fairly sharp. Don't forget the inside of the cut either. A photo (PerformanceFlute5) of the important acute angle of cut is included in the PerformanceFlute.zip archive. (The actual cut is made starting 1" into the the tube, not at the end as illustrated.) Higher notes generally require more wind, and slit directly into the wind. Lower notes respond to less wind, with slit only partially into the wind. So pitch change entails slightly rotating the tube clockwise as pitch lowers). THE FLUTES: Sliders One 5' length of 1" diameter (SCH40) PVC (< $3) will make pitch sliders for four pipes. Cut each slider to 11 1/4". Next, a "snugging" felt tip for each slider must be attached. On one of the felt blankets, trace the circumference of the *outer (thin) tube* and, with a pair of shears, cut out the resulting circle. Peal off the back of the pad and *carefully* center the sticky felt on one end of the slider. (The pad is difficult to remove once attached.) For maximum adhesion, hold it down firmly for a short period of time with the palm of your hand. Now, while centered, push the felt end of the slider into the tube, then move it around in all directions short of the slit, assuring a secure fit. (The edge of the pad should now fold over the end of the slider somewhat.) If the adhesive gives way or loosens at any point, secure as needed with some super glue. You may want to mark the following distances around the circumference at the further end of each slider: 1 1/4" and 2". These indicate the longest length that should be inserted into the tube: 1 1/4" for 13" tubes, 2" for 12 1/2" tubes. You might also make a comparable 2" mark at the felt end, to indicate the outer extreme of the slider's useful length (and so it won't readily fall out). PERFORMANCE As with the "Banshee" flute, this variant requires a stiff wind - in this case, a fairly even and continuous one. The individual tubes can be made to start and stop sounding in two ways: 1) by moving them around the pole, in and out of the prevailing wind; or 2) by rotating them - tube and adapter as a unit - within the snap tee. For this second method (preferred), you should loosen the adapter within the tee, and firmly secure the tube into the adapter (making it immobile). As mentioned above, slight adjustments in rotation will also need to be made as pitch is changed, in order for notes to continue to be heard. While working with the pipes in performance, you will probably want to use one hand (or an assistant) to steady the vertical pole, preferably from the top (and for an assistant, from the opposite side from the pipes). Suggested performance procedure: Preselect and set an opening chord; from silence, bring in one note at a time until all are sounding; change single tubes by a half- or whole-step to another desired chord; repeat as desired. At the end, remove individual notes until silence. I envisage this process moving slowly and evolving over time, with each new chord given substantial opportunity to be heard (especially taking into account variation in wind speed). Indeed the "performance" could be set up as an "installation", with only occasional changes of single tones over a long period (even hours). Performances can be improvised or planned in advance. Planning could consist of a series of specific chord changes and "parts" specified for designated tubes. To assist in pitch change, sliders could be marked at specific pitch points, associated with specific tubes. With such coding of the flutes, chord changes could be made whether or not the wind was blowing at the time, or only when the flute was turned into the wind (pitch change heard immediately). These possibilities especially apply to "installations", where listeners (as well as wind!) may not always be present, or may come and go at random. Thus a "performance" could occur whether or not wind or listeners were present at a particular time - a semi-environmental "happening." In preparing such performances, I have found the use of a large circular fan (a consistent wind source) to be invaluable - especially where beaches and mountains are not readily available! The fan also greatly facilitates demo recordings; such a recording is a companion to this article. [1] I'm indebted for inspiration and practical advice to Bruce Yeany's YouTube video on Slide Whistles (my Performable PVC Wind Flute is essentially a special case of slide whistle). The URL: https://www.youtube.com/watch?v=2-A2_A_k2fE . Near the end of his video he crafts an ingenious whistle largely from a single carrot! PERFORMANCE FLUTE PHOTOS (PerformanceFlutePhotos.zip) PerformanceFlute1: Overall view of Performance PVC Wind Flute Important Note: I no longer use wood dowels (here illustrated) as sliders; I use the 3/4" SCH40 PVC described above. (When wood dowels are left outdoors in the rain, I find that they can swell and seize up inside PVC pipe!) PerformanceFlute2: Detail of pipes, slits into wind PerformanceFlute3: Even more detailed view PerformanceFlute4: 12 1/2" and 13" pipes with dowels (now PVC sliders) PerformanceFlute5: View of important *acute angle* of slit. (Actual cut begins 1" from end of tube) PerformanceFlute6: Recommended felt tip on Left (the felt more prominently folds over the end of a PVC slider); the alternative packing foam tip on Right no longer applies (it only works with wood dowels). PerformanceFlute7: Overall view of Performance PVC Wind Flute with alternative Sandgrabber Anchor PerformanceFlute8: Closeup of Sandgrabber Anchor in loose garden soil