Instructables
Picture of Homemade well tuned pan flute
I'm kinda strange guy. I like really zillions of things, very different one another. For example, I'm studing math, I'm learning to play violin, I like Irish music... I also like making things. To conciliate this last passion with music I made a pan flute, an ancient instrument belonging to various cultures. Here is the process that will bring us to an almost perfectly tuned pan pipes.

This Instructable is splitted in two parts: theory and practice. If you are not interested in all the math and physics behind the project, you can jump directly to the practice section. If you want to know how to retrive all measurement, or even to customize your pipes, then proceed with next step.

 
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Step 1: Theory

The (not-so-)boring part.

As I've aforementioned, you can skip this passage if you don't want (or need) to understand the physics beyond a pan flute.

OK, if you're reading those words you want to know more. I'm here for this!

A pan flute is a mere group of tubes with a closed end (called closed cylinder, even if one end is open). Each tube have a different length but, usually, the same diameter of all other tubes.
The length of the tube influence the pitch: longer tubes produce lower notes, shorter tubes produce higher notes.
The inner diameter of the tube influence the speed of blow needed to make the sound audible: smaller diameter means less blow, greater diameter means more blow.

Pretty simple, uh? No math, no strange formulas...

Now we need to find a precise relation between tube length and note pitch. Luckily, some physician (well, actually a lot of physician) already studied this matter creating and developing a branch of physics called acoustic. So we can "stole" their results to serve our scopes.

The formula we need is the one in the first pic. Here is the meaning of various symbols:

- L is the length of the tube
- v is the speed of sound
- f is the frequency

Fine. Now we need to determine which notes we want to produce, and their frequencies. I'm going to make a full octave pan flute, so I need 13 tubes: C, C#/Db, D, D#/Eb, E, F, F#/Gb, G, G#/Ab, A, A#/Bb, B and C again. Each tube will produce a note a semitone higher than the previous one and a semitone lower than the next one.

Since it's is too generic saying "I want to play an E", we must specify also the octave. In my case the first C is a C4 and the last C is a C5. This make the A an A4, with a frequency defined to be 440 Hz (modern concert pitch). From this we can determine all other frequencies using the second formula (second pic, obviously). The n is the number of semitones between the note we want and the A4. If the note is lower than n will be negative, if the note is higher it will be positive.

Step 2: Theory part II - Calculations

Picture of Theory part II - Calculations
virtual3d.jpg
Now we have the basis to determine the tubes length. First we find the frequencies of all notes we choose. This can be done easily with Excel, Derive, Mathematica, even with Windows' Calc.

As a math student I love Mathematica, so I will use it. However, "my" frequencies are
261.6, 277.2, 293.7, 311.1, 329.6, 349.2, 370, 392, 415.3, 440, 466.2, 493.9, 523.3
rounded to first decimal digit, measured in hertz. Using the first formula shown in the previous step we obtain the list of length:
31.69, 29.91, 28.23, 26.65, 25.15,  23.74, 22.41, 21.15, 19.96, 18.84,  17.78, 16.79, 15.84
rounded to second decimal digit, measured in centimeters.

A "virtual" pan flute made using those length and laying all tubes on a table is shown in the first pic. The external diameter of those pipes is 2 cm, maybe too wide (and bigger than the one I've realized).

The disposition of tubes, in my opinion, is not so good, because of my lack of memory. If you ask me where is a note on a piano I can find it almost instantly, but if you ask me the same thing on this arrangement I will need at least two seconds, a really long time if you are playing something. So the disposition I chose is similar to that of key on a keyboard, but the accidentals (black keys) are nearest to the player and have been lowered. The second image is another virtual model of the pan flute made this way.

Later I will explain how to dispose everything even better.

Theoretic lessons are gone, now let's do something more practical!

Step 3: Materials and tools

We cannot start making something if we don't have anything to start with.

Materials we need:

- about 3 m of metal or plastic pipe (if you use metal try to avoid copper)
- duct tape of any kind
- strings/shoelaces/yarn/whatever you want to keep tubes together
- 13 pieces of whatever you can use to close one and of a pipe (coins, metal or plastic scrap, wood, cardboard... remember that it will cover the end from outside, and cannot be inserted like a cork on a bottle because this will shorten the air column and change the note produced).

Please make sure that you can cut all pieces from your pipes because it may be difficult to join two pieces together without compromise the sound. My local store sells only 1 or 2 m long tubes, and with 3 short (1 m) tubes you can do every pipe. The inner diameter should be not too big nor too small: a 1-1.5 cm of inner diameter is fine.

Tools we need:

- a saw or a tube-cutter
- a measuring tape/long caliber/big printer (I will explain this later)
- something to write on tubes
- needle files
- tuner/good ear (optional)
- clear glue (optional)

If you don't have one, I suggest to buy a tube-cutter: I've bought a small one, suitable for tubes from about 0.5 to 2.2 cm, and it costs me only 2 € (less than 1.5 $). If you don't know how to use a tube-cutter and you cannot figure out by yourself feel free to ask.
The caliber will allow you to make more precise measurements, but you can use a measuring tape with a sign every millimeter without loosing too much tuning. Only a really good ear can sense a difference of a few cents. If you have access to a printer that can use large formats (at least 35 cm on one side), you can print out a schematic with precise measures made with any CAD software. This is my favourite method, but this time I cannot follow this way because my printer is incapable of such dimensions.
The tuner (or a good trained ear) can be useful to test each tube once cut and cleaned. It shouldn't be necessary, but it's a further warranty.

For finishing (optional):

- sandpaper of various grit
- a Dremel-like tool (optional but very useful)
- a lot of patience, a googolplex tons of patience if you want to do everything by hand

Step 4: Measuring and cutting

filing.JPG
tubes.JPG
Now we have to start measure things.
We need 13 tubes with various length, from slightly more than 15 cm to slightly less than 32.
To optimize the space and to use only three 1 m pipes, we will cut each pipe as follow:

1st pipe: 31.69 cm + 29.91 cm + 22.41 cm + 15.84 cm (low C + C#/Db + F#/Gb + high C, about 2 mm left)
2nd pipe: 28.23 cm + 26.65 cm + 25.15 cm + 19.96 cm (D + D#/Eb + E + G#/Ab, almost nothing left)
3rd pipe: 23.74 cm + 21.15 cm + 18.84 cm + 17.78 cm + 16.79 cm (F + G + A +A#/Bb + B, less than 2 cm left)

As you can see, I wrote also the note corresponding to each section. Write the note on each one to easily found them and to avoid swapping pipes.

If you use an handsaw make sure it can cut the material or you will be ruining it. Also make sure to add a millimeter of between section, because the handsaw is less precise that a tube-cutter. If you have a tube-cutter, try to put it with the blade exactly where it should go and use a working glove to turn the knob: it's very tough.
If you cannot print a life-size plan or you don't have a caliber with a tolerance of 0.01 (and big enough to measure 32 cm), you can round to the first decimal digit, but make sure to round properly (for example, 31.69 will become 31.7, 29.91 will become 29.9. The general rule is: if the discarded part starts with a digit less than 5 then you left all unchanged; if it starts with a digit greater or equal than 5, then add 1 to the last digit of the remaining part).
The best way to cut the tube almost exactly (unless you use the printer) is to measure only one section and cut, then measure the next one and cut, and so on.

Every time you cut a piece of pipe, file down all burrs, inside with a rounded needle file, and outside with a flat side. File also the section to make it planar, especially if you use an handsaw.

Step 5: Cleaning (optional)

If you like the finiture of your tubes you can skip this step.

I've brought aluminium pipes (light and good-looking), but they have a paint I don't like. For another project (a tin whistle) I've started to sand them by hand with a medium grit sandpaper. How boring!!!
With a Dremel tool you can speed up the process, unless you prefer doing it by hand, but be aware that you will change the sandpaper bit many, many times.

This time, since the whistle was less than 40 cm long and the sum of lengths now is more than 295 cm, I've decided not to sand it. Maybe I will decorate my pan pipes in another way.

So, the image of this step is from my previous instrument, a six-holed pennywhistle made of aluminium, wood (juniper), and electrician tape. I'm very sorry that I haven't take any picture... Maybe I will do another tin whistle, and use the project for another Instructable.

By the way: the tin whistle sounds good, is well tuned, and it's a C-whistle. The next one I will make will be a D-whistle, the traditional Irish tuning for this instrument.

Step 6: Closing the tubes

Take one tube. Take the thing you want to use to close the end and close the end. Then repeat for another tube, until you have no tube open.

Do you want some more directions? OK, then.

Since the process depends also on what you have choosen as cap, those can be only general directions. I choose to use light cardboard.

File slightly the end surface of the tube to create something the glue will adhere to. Then put some glue on the edge, avoiding the internal of the tube, take a square of cardboard slightly larger than the tube and glue both things together.
When the glue is dry remove the external carboard with a knife, a scalpel or a pair of scissors. With some duct tape, maybe a colored one, cover the edge to avoid any air fugue.

That's all, folks!

Well, for this step...

Step 7: Putting everything together

Picture of Putting everything together
Now we have a set of 13 tubes. We need to arrange them in a practical way, so we start by taking all "white" tubes, e.g. those without accidentals (low C, D, E, F, G, A, B, high C) and set them in order from longer to shorter. Obviously open ends will go on the same plane. Start lying a strip of duct tape on the table, then add one tube at time on the tape, following the right order.
Take the yarn and wrap 6-7 times around all the tubes, then wrap 2-3 times between tubes (see images). Knot the end when you are done.

Once done the first row, we need the accidentals row. So take the C#/Db and D#/Eb tubes, and follow the same process as before. Then repeat with F#/Gb, G#/Ab and A#/Bb tubes.

Now you should have three partial pan flutes: one with 8 tubes, one with 2 tubes and one with 3 tubes.

Take the 8-tubes and the 2-tubes pan flutes and lye the latter on the first (see first image), lowering the accidentals by 1-2 cm. Try to play some notes. If you hear 2 notes when you play the C, D or E tube, then lower the 2-tubes group. If your nose touches the open end of the C, D or E tube when you try to play a C#/Db or a D#/Eb, then raise the 2-tubes group.
When you find the right place, take a piece of yarn and wrap it around the ends of the first group of five of tubes (C, C#/Db, D, D#/Eb, E). Make 2-3 turn, then knot the end and trim the exceeding yarn. Do the same on the top.

Finally repeat with the 3-tubes pan flute.

You can use some glue to the yarn to fix it in place.

The result of those operations should be similar to the one depicted in the last two images.

Step 8: Further improvement: adding an higher octave

Picture of Further improvement: adding an higher octave
The pan flute have a problem: each tube can produce a single note, so if you want a full 3 octave flute you have to make 36 different tubes.

But we can take advantage of physics!

OK, maybe there's the need of some other explanations. Two tubes of equal length, but one closed at one end and the other completely open, produce the same note within two adjacent octaves. For example, a closed tube that produce an A4 (440 Hz) is 18.84 cm long. The same tube opened will produce an A5 (880 Hz). We can see this fact from two formulas in the first image.

Actually, an open tube requires a correction factor that depends on frequency and inner diameter, but the difference should be barely noticeable.

So, finding a way to open and close the tubes at wish will give us an extended range: for example, if the original range is C4-C5, the final range will be C4-C6. Without even adding a single tube!

Step 9: Further improvements: adding another higher octave

But what if we want a note higher than a C6?

Again, the answer came from physics. How we can do that? Simple: creating an hole in the tubes.

Wait, don't take your driller too soon. We need some calculation, obviously.

First, if we make a single hole, its size doesn't matter. If you want to add two or more holes for each tube, than the things became complex. So we'll drill only one hole.

We can calculate the distance of the hole center from the open end using the same formula I've shown in previous step (see first image). This time we know the frequency (if you don't then go to the second step). All we need to do is take the frequency of the pipe, double it two times and calculate the value of L. For example, the D4 has a frequency of 293.7 Hz, so the D6 has a frequency of 1174.7 Hz. So the hole center must be 7.06 cm from the open end. If you make a large hole (like 5 mm of diameter), the approximation will be better than a smaller hole.

However, reaching the central tubes with your finger can be difficult, so again finding a way to keep closed all holes and open them simultaneously is a great idea. I'm thinking about the key system of a flute (or sax, or similar systems), but I'm not so good in making such precise works...

This method only works when you can also open the ends, because the note produced is noticeably different if the end is open or closed. This is due to harmonics produced by the section behind the hole. So, the best thing (maybe it's only a dream) is a mechanism that open both ends and holes with a single lever, and only the ends with another lever. This way you can have a pan flute whose range is, for example, C4-C7, three octaves!

RyanKranz1 month ago

Hey buddy, your calculations are all a little off, by like a cm. Did you take the speed of sound as something funny? Press a wrong key?

34029 = speed of sound in cm/s

34029/(4)(261.6) = 32.52cm, not 31.69cm.

Drako84 (author)  RyanKranz1 month ago
As I said in a previous reply, the speed of sound can vary greatly based on air pressure, air temperature and even air composition. Basically, any source you look into for the "real" value reports a different number: for instance, Google says 34029 cm/s (your value), but Wolfram|Alpha says 34320 cm/s, Wikipedia says 34300 cm/s, and so on.

I'm sure there is a way to cope with those differences, but remember that just by playing in a room with an air conditioner can change the pitch compared the outside because of the lower temperature and humidity.
chikengirl5 months ago

I am going to try making one of these. Hopefully it works well. :)

demiperson6 months ago

For the panflute I need a F4 to F5 instrument please help.

Drako84 (author)  demiperson6 months ago

You can obtain the data you need from the formulas in step 1. However, I made those calculation for you.

I assume you need a full chromatic pan flute, so the notes will be F4, F#4/Gb4, G4, G#4/Ab4, A4, A#4/Bb4, B4, C5, C#5/Db5, D5, D#5/Eb5, E5, F5.

The frequencies you need are 349.2, 370.0, 392.0, 415.3, 440.0, 466.2, 493.9, 523.3, 554.4, 587.3, 622.3, 659.3, 698.5 hertz.

With a speed of sound set at 342.2 m/s, the lengths you need to cut are 24.5, 23.1, 21.8, 20.6, 19.4, 18.4, 17.3, 16.3, 15.4, 14.6, 13.7, 13.0, 12.2 cm, or 9+21/32, 9+3/32, 8+19/32, 8+1/8, 7+21/32, 7+7/32, 6+13/16, 6+7/16, 6+1/16, 5+3/4, 5+13/32, 5+3/32, 4+13/16 inches.

Hope this helps!

Thank you, you helped a lot, friend! But since taking the opportunity, would you please make a tutorial of these teaching to make a tin whistle?

Drako84 (author)  RICARDOMILITAO7 months ago

I know it's taking a lot of time. A tin whistle is surely harder to make than a pan flute, because you must have all the holes with the right size and in the right position. For not to speak of the mouthpiece and the embrochure hole!

However, reading your kind comments make me want to try again as soon as I can. I don't have much time, now that I'm not a student anymore, so please be patient.

Thank you, you helped a lot, friend! But since taking the opportunity, would you please make a tutorial of these teaching to make a tin whistle?

Very good tutorial. But how do I produce them in those different diameters you used here? There is some calculation that allows to know which length tubes of other diameters?

Drako84 (author)  RICARDOMILITAO7 months ago

Thank you!

The pitch of the note doesn't depend on the diameter, only on the tube length. However, tubes with small diameters can be hard to manage (a small difference in blow force can cause a big difference in tone), and tubes with large diameters can require a lot of blow.

Think of a bottle and a glass: with the bottle is easy to produce a sound by blowing on the opening, but with a glass it's almost impossible.

The diameter counts only when you try to make some holes for fingering, but this will make things very complicated...

Hope this helps!

Jonas.B2 years ago
Superb instructable! :)
I have one question though:

On wikipedia the speed of sound in room temperature is said to be 34320 cm/s, but when i check your calculations, it seems the used number was 33150 cm/s. Which one of us calculated wrong?
Drako84 (author)  Jonas.B2 years ago
Thank you!

I think none of us calculated wrong, simply because the speed of sound depends not only on temperature, but also on a lot of other things, for example on altitude or density of the air. Since the pan flute cannot be tuned once made, you must adjust the blow speed and force to raise or lower the frequency.
Very good and educating instructable!! Thanks!!!

One advise: Maybe it would be "safer" to cut the tubes a little bit longer (a few mm). Then, using the needle file and a good tuner you can tune each tube at the exact pitch. ;-)
I think you meant physicist, not physician.
Daftehh3 years ago
One more thing added to my to-do list
also, you could use epoxy to bind the tubes together
arami3 years ago
Great place to start for making wind instruments! I would like to point out that physicists (not physicians) are the ones that acoustics... But other than that, great basic explanation on how pan flutes work.

Thanks :)
trubshac4 years ago
Brilliant instructables.  I like the theory as well as the practical explanation.  We've just made one out of the plastic coated mild steel handles of 3 floor brushes that we got from the poundshop!
Our first attempt just used insulating tape to close one end of the tubes - this didn't work at all.  We then tried stiff cardboard held in place with insulating tape which worked perfectly.

AndyGadget4 years ago
Neat Instructable, but a video of you playing them would really add to it.
I only found out recently that the way they're played in the Andes is for two players to blow alternate notes on the pipes, so each player is only playing half the tune with the notes bouncing back and forth between them.
Drako84 (author)  AndyGadget4 years ago
Thank you! Well, I haven't posted a video mainly for 2 reasons: videos my camera can take have a very poor quality; and I'm not so good in playing...
After all, Stradivari was an excellent violin maker, but a poor violin player.

The way Andes performers play their instrument is very interesting, I'd like to see them in action.
Good point about Stradivarius.  I've never seen a video of him playing anywhere ;¬)
I can't find a video of the alternate blowing either.  We get a few Andean bands busking in the High Street during the year and one of them explained and demonstrated the technique once.  Since then I've seen others do it.
Doctor What4 years ago
 Lovely!  My family used to participate in Renaissance Faires (well, they still do, but I don't!).  Using instruments was incorporated heavily into our character designs.

My stepmom played the fiddle and a mouth harp.

My dad played the Tabor Drum, the fife, the flute, and a dozen other random instruments.

I also played the flute.  (I liked juggling better than musical instruments)

We performed with an Irish Stepdancing group.  It was quite fun!

This would be great for those who can't find a pan flute.  (I'm also excited for your tin whistle!)

Very nice job!
Drako84 (author)  Doctor What4 years ago
Great! Renaissance Faires! I love them!
Sadly, I've seen only one... and desolate...

However, I hope I will not make you wait too long for the tin whistle. Stay tuned!