Even the valves on instruments such as the trumpet do not change this: they alter the length of the pipe, but they don't allow air to escape before the end is reached. All the pipes we have considered before - whether open at one end or both, whether cylindrical or conical, and whether made from wood or brass - have boasted continuous bores. Given that the longest open pipes are typically 32' long, this means that an organ with stopped 16' pipes can produce the same, deep pitches as larger instruments).įigure 4: Blowing a note on the Shakuhachi with all but the lowest hole closed.Thirdly, the Shakuhachi has holes.
Too big aperture flute series#
These generate the odd-harmonic series discussed last month, and offer a significant advantage to the organ builder for any given pitch, they need only be half the length of their open brethren. There is a class of organ pipes called stopped flutes that are closed at the top using wooden plugs. it's the only flute that generates no even harmonics (this is not strictly true, although it is true for orchestral flutes. Indeed, all the instruments of the flute family are 'open' if they have holes, so the pan flute proves to be an oddity. Therefore, as explained in part 24 of this series (see SOS April 2001), the standing wave within it contains both odd and even harmonics. and so on, as the increasingly rapid up/down motion excites higher modes of oscillation in the pipe.įigure 3: Blowing a note on the Shakuhachi with all holes closed.The second difference between the pan flute and the Shakuhachi is that the latter is open at the bottom. how hard you blow), which explains why, when you blow harder into an instrument of the flute family, the note jumps from the fundamental to the second harmonic, and then the third, and the fourth. It turns out that the speed of up/down oscillation is roughly proportional to the speed of the air stream (ie. Now, the net atmospheric pressure is downward, and we quickly move back to the situation shown in the first diagram.įigure 2: The pressure exerted when air passes over a sharp edge placed in the stream.If the edge is connected to a pipe of some sort, it doesn't take much of a leap to realise that, at some frequency, the up/down vibration of the airflow will match the pipe's resonant frequency, and a standing wave will result, generating a sustained note. If the upward pressure in Figure 1 is sustained for a fraction of a second, the jet is pushed upward, and we soon reach the situation shown in Figure 2. Figure 1: The pressure exerted when air passes under a sharp edge placed in the stream. The net effect is therefore an upward pressure that lifts the machine off the ground. This is the principle that keeps aeroplanes in the sky: air moving faster over the top surface of the wing generates less pressure than that moving more slowly along the shorter underside. At that moment, the part of the stream shown in orange is moving minutely faster than that shown in red, so the air pressure on the flow tends to press it upward. If you consider Figure 1 (below) you can see an instance when a jet of air blown against such an edge is deflected downward. Made from a single piece of bamboo, this is another instrument that requires you to blow over an aperture, but it differs from its more primitive cousin in three ways.įirstly, you excite the air by blowing over a sharp edge at the mouth of the pipe. This month, we'll look at another of the flute family, and see whether we can synthesize it using something rather simpler.īut first, I want to take a look at the Japanese Shakuhachi.
Too big aperture flute Patch#
Successful though it was, the patch was a monster, and not one you could create on any basic (read. Last month I discussed the sound of the pan flute, leaving you with a diagram that showed how you could use a large modular synth to create a remarkably accurate simulation of the instrument. The Monty Python team once famously claimed that being able to play the flute was a simple matter of 'blowing here, and moving your hands up and down here'.
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