Organ Pipe Calculator

The pitch of the pipe, specified as a MIDI note number, where 60 is Middle C (261.6 Hz), and incrementing by one always raises the pitch by one semitone.

False indicates the end of the pipe will be open to the environment, true means it will be closed, or stopped. This affects the length of the pipe, and it more subtly affects the width, mouth height, and windsheet thickness.

The thickness of the plywood you are going to use for the top part (resonator) or the pipe. This also determines the wall thickness of the 3d printed part.

The thickness of the felt you are going to use to line the inside of the plywood tuning slide.

The length of the stem that lets air into the bottom of the pipe. This does not affect the sound of the pipe.

The pipe will be shortened by this many half-steps so that it can be tuned down to the correct value by lengthening. Normally a stopped pipe would be tuned up by shortening the pipe, but because of the restrictions of laser-cutting, here we take the approach of tuning all pipes by attaching an open or closed slide to the outside of the pipe. If you need your pipe to be too long so it can be stopped with the traditional method, you can enter a negative number here.

Width of the kerf of the laser (or router) used to cut the plywood.

This makes the pipe wider or narrower than it 'should' be. Positive values make the pipe narrower, negative wider. Should range from about -10 to 10, with negative numbers having a more string-like sound, and positive having a more flute-like sound, and values near 0 are for principals. +4 means this pipe will be as wide as a pipe 4 semitones higher should be. This page uses a 17^th halving ratio. more info.

This number, together with the air pressure, determines the wind-sheet thickenss of the pipe. 2 will give the pipe maximum efficiency and bring out the fundamental tone. Increasing it will bring out the higher harmonics, and above 3 the pipe will be overblown. more info.

The air pressure, above atmospheric pressure, of the pipe's air supply. Used in determining the windsheet thickness. (See Ising's Number, above.)

The frequency of the pipe in cycles per second.

The inner width and depth of the pipe. Calculated using this.

The height of the opening at the front of the pipe. This is related to the frequency of the pipe, and whether it is open or closed. More info.

The width of the thin slit where air exits the pipe. This has to do with the Ising number and the air pressure of the organ's air supply, which you can adjust. Make sure your 3d-printer has a high enough resolution to make this gap accurately. More info.

The total volume of air that will flow through this pipe in one second, given the supply pressure and the windsheet width. More info.

The outer diameter of the air inlet stem at the bottom of the pipe. This will grow in 5mm increments as the pipe increases in size.

The total length of the functional part of the pipe, from where the air exits the mouth of the pipe, to the top of the pipe (for a closed pipe, the top of the inside of the pipe). This will be the theoretical length of the pipe calculated using this, minus the tuning headroom.

The length of the plywood resonator part of the pipe. That is the Pipe Length (as above), minus the part of the pipe length that is 3d-printed.

The tuning headroom, in millimeters. You can adjust it in semitones in the "Settings" panel. This is approximately how much length you will, in theory, have to add to the pipe to tune it down to the correct pitch.