A cane whistle is a hollow tube 15-20 cm long with a plug at one end and a rectangular window about 2 cm from it, so that breath squeezed through the narrow gap under the plug splits on the window’s edge and sets the tube sounding. Adjust the plug and the gap until the note is clear, since too wide a gap gives a breathy hiss and too narrow gives silence or a squeal. The note is near v divided by twice the sounding length, and every whistle needs tuning by trial.
Part of Music & Simple Instrument Making
End-blown cane and bamboo whistles with an internal plug, and how the windway and window are adjusted until the tone speaks.
The Gap Under The Plug Does The Work
The parent article describes the build: cut a hollow reed, bamboo, elderberry or willow section 15-20 cm long, carve a rectangular window about 2 cm from one end, and fit a plug from the end to just before the window, leaving a narrow air channel between plug and wall. Blowing sends a flat sheet of air across the window, and the sharp far edge of the window splits it and drives the tube. This is the same principle as a modern recorder.
Despite the name, a “reed flute” here is a tube made of cane, not an instrument with a vibrating reed; the vibration is in the air stream itself.
What You Need
- Hollow cane, bamboo or elder about 15-20 cm long; see Frame Materials, Wood, Bamboo & Salvage for bamboo
- A plug carved from soft wood, wax or clay that fits the bore snugly
- A sharp knife to carve the window; see Sharpening
- A bow or hand drill for finger holes; see Drill and Auger
Method: Make And Adjust
Step 1: Cut the tube with a clean end. Keep the bore free of obstructions; elder needs its soft pith pushed out.
Step 2: Carve the window, about 2 cm from the blowing end, cutting a rectangular opening with its far edge sharp and bevelled to a knife edge.
Step 3: Fit the plug from the blowing end to just short of the window, flattening one side of it so a thin air channel remains. The channel should be about as wide as the window and as thick as a thin card; this is a craft rule of thumb I recall, not a sourced dimension, so adjust by ear.
Step 4: Test. Blow gently. A clear steady note means the channel and window are about right. A breathy hiss means the channel is too thick or the edge is blunt; silence or a squeal usually means the channel is too thin or misaligned. Move the plug, reshave the flat, and test again.
Step 5: Add finger holes only after the open tube sounds. The parent article suggests starting with 3 evenly spaced; drill small and enlarge as in Hole Spacing & Tuning.
Worked Example: Expected Pitch
Take the distance from the window’s cutting edge to the open end as 0.18 m with a bore radius of 6 mm. Treating it as an open tube, f ≈ v ÷ 2L = 343 m/s ÷ (2 × 0.18 m) = 953 Hz. Adding about 0.6 × bore radius = 3.6 mm of end correction at each end (a standard value I recalled and did not verify here) makes the effective length 0.18 + 0.0072 = 0.1872 m and gives 343 ÷ (2 × 0.1872) = 916 Hz. The real note will probably differ by tens of hertz because the window geometry is not a simple open end, so tune against a reference.
Overblowing. An open tube blown harder jumps to its second mode, an octave higher at twice the frequency (here about 1,832 Hz). A tube stopped at one end overblows to three times the frequency, not twice.
Common Mistakes
- A blunt window edge. The air stream needs a sharp edge to split on; sharpen or recut it.
- A tilted plug. The air stream wanders off the edge.
- Expecting a calculated note to be exact. Cut long, test, and adjust.
Safety
Elder wood and cutting
Fresh elder wood and leaves are reported to contain compounds that release cyanide, so let elder dry and do not chew or suck fresh wood (recalled; avoid). Carve away from the body with the tube braced; a slipped knife on a round tube is a common cut. Do not paint the mouthpiece with salvaged paints; old paint may contain lead.
What’s Next
- Learn next: Hole Spacing & Tuning — placing holes to a scale
- Combine with: Panpipes — the other cane instrument