Slide Whistle (class project)
Instrument type: aerophone, fipple flute
Difficulty to Make: capable 9+ years old
A fun instrument you can play a recognizable tune on... well almost. Children get a real sense of achievement when it makes a whistle for the first time.
How a fipple creates a vibration
As the illustration shows, the air going through the windway reaches the fipple edge and goes either in or out of the tube. This depends on the air pressue difference between the inside and outside of the tube. The oscillating air, switching sides is the sounds vibration. I believe this explains why it is easier to get the fipple to make a sound when the end of the tube is blocked off. And easier to make a slide whistle than a recorder. click on the link for the instructions in a pdf version Make slide whistle pdf
Slide Whistle Instructions
Tube 16mm internal diameter electrical conduit, bamboo or other tube of similar diameter
Plug 25mm length wooden dowel or cork, of the
same diameter as the inside of your tube.
Sliding stopper dense foam
Stick thin wire knitting needle, skewer or other stick
80 grit sandpaper, small hacksaw, hotglue gun, drill/bit, pencil, circle cutter. Note: make circle cutter by sharpening the end wall of the same size tube you are using for the whistle or even the end of the whistle. Sharpen like a pencil from the outside with sand paper or sharp knife.
1 Cut tube 150mm length, fipple plug 25mm length,
2 Make sliding foam stopper with prepared circle cutter by twisting the sharpened end into the foam.
3 Make two marks, one from the end of the tube the same length as the wooden fipple plug, and another mark a further 8mm along the tube.
4 At the plug length mark on the tube, use a saw to only just cut just through the wall of the tube. Saw a cut at the 2nd mark, on an angle back to the bottom of the first cut. Cutting a triangular piece out of the tube. Use sand paper to make a clean edge to the tube wall in the hole (fipple edge). This edge should have an even curve and be free of sawdust.
5 Sand one side of the fipple plug to make a flat ramp.
6 Insert plug into the tube with the ramp pointing upward directly at the cut in the tube.
Note The air hitting the sharp edge of the tube makes the whistle sound. Test for whistle. Blow gently into the tube at the fipple end. Does the fipple make a clear whistle sound? Does it make a sound when you block up the other end of the tube with your hand? It is ok If it only makes a sound when blocked up. Carry on to make the sliding stopper.
No whistle! Try the following.
7 If it feels hard to blow air through the whistle, push the plug out and sand more off the ramp to let more air into the whistle. Test again
8 Make sure the airway is clear of any saw shavings.
9 Look through the mouth piece. Does the ramp point directly towards the fipple edge? push the plug further into the tube, so it is closer to the fipple edge. Test again
10 If nothing works, make a new plug. If it still wont make a whistle you will need to make a new fipple hole in a new tube.
11 When the whistle is making a clear sound the fipple plug should be glued into place with PVA . Make sure the plug is glued in the correct place before leaving to dry.
Make the sliding stopper
12 Push the stick through the middle of the foam stopper and 8mm out the other side. Use a small amount of hotglue touching the foam and stick, on both sides of the foam, to keep the stopper from sliding along the stick.
13 Try sliding the stopper up and down inside the tube. Can you slide the stopper easily? Try a small amount of neutral oil or soap on the sliding stopper.
14 Blow on the whistle and slide the stopper. Does it change the pitch of the whistle? If your stopper is too small or uneven, air is escaping past the sliding stopper and you will need to make a new one
Make an end plug to stop sliding stopper from coming out the end. Make a small plug from foam or dowel. Drill a hole big enough for the stick to slide through easily. Thread the plug onto the stick and insert plug into the tube. Glue end plug into tube if necessary.
If using a wire stick you can bend the stick back up the tube to make sliding easier.
Use thin saw or sandpaper to make mouth piece smaller.
Cover tube with book covering or good quality paint.
• If you can get more than one octave you have done well. The fipple needs to be carefully made to make two octaves.
• The length of the fipple hole makes a difference to the quality of the whistles' tone. A recorder is made with a short hole to produce a clean tone. A longer hole makes a more breathy sound.