I’ve had a nice, sturdy piece of bamboo about 5.5 foot long staring at me for a couple of months now, begging to become a flute. I input my numbers into Flutomat, and it seemed that even with my large hands a D flute was not practical. (In retrospect, this should have been a sign that I was not using the tool correctly)
A flute in G seemed more doable, leaving me with a good sized chunk of bamboo should I want to make another. (Or screw up my first attempt, which is more likely)
Well, I seem to have screwed it up. I measured the wood, cut it to length, cleaned up the node in the middle, determined the position of the embouchure hole, and carefully drilled and sanded the hole.
Time to play my first note…
C - Soft, and a little flat but definitely a C. First harmonic, a very sharp B. (Flatter C?) Second harmonic, a flat G. Next, a flat C.
I’ve obviously put garbage into the Flutomat, but I think I can salvage this, and get that D flute I had originally planned.
The flute as it stands is similar in proportion to my Travis King D flute, though with a more or less cylindrical bore.
Can anyone help me discover my error before I start cutting tone holes? No doubt after trying so many variables on Flutomat I inadvertently missed a key variable, leaving me in an unexpected key.
Flutomat is applying the “key of G” to the XXXOOO note, not XXXXXX. I don’t know enough about Flutomat to know how you got there, or how to correct that misinterpretation.
If that was in the documentation, I certainly missed it. I don’t understand it, but it agrees with the pitches I have so far.
I purposely cut the blank a little long so that I had some wiggle room to get to the desired pitch. it’s looking like I should be able to trim it down to a D if I don’t mess up the other calculations.
But not today… I’ve already made my quota of mistakes for the day, and I still have a rehearsal to attend this evening.
It’s not very obvious, but if you click the red “i” by the logo it explains the reason. Quote:
“N.B. I mostly play the North Indian bansuri style of flute, with large finger holes and key note played with three finger holes closed. Western folk flutes tend to use six fingers down (a perfect fourth down, or fifth up) as the key note. So what I call a C flute, others will think of as a G flute, etc. This may be worth considering when viewing the following examples.”
Got it. Does this mean that the note 000 000 is a C-natural or a C#? I’ve got a feeling this is something I don’t want to mess up
I have enlarged the embouchure hole to the recommended 10mm and the pitches are… better, but not great. (Probably because I guessed at the position of the “stopper” node… I can elongate the embouchure hole in the right direction, but that will likely give the tiniest of improvement) I’m not cutting any tone holes until I get a good fundamental D, and recalculate the rest from there.
I think it’s calculating for C#5 for all open fingering. If you click the “Frequencies” checkbox, it shows you predicted frequency for the fingering that first opens that hole and it lists 554.7 Hz.
My understanding is that Bansuri players half hole the top hole when playing the solfege. The frequencies also seem to suggest flutomat is calculating with just intonation which I believe is typical for that instrument.
I had the calculator set to mm, and it was not lining up with the same points when set to inches.
As it turns out, Flutomat sets end of flute at 456.1 mm, but when switched to cm it’s 52.09! The latter is correct when compared to inches.
This sounds like wise advice.
[EDIT] Except for the fact that my “nice flute” has a conical bore, tapering 4.3mm from the start of the upper joint to the end of the flute. I should not be surprised that some of the measurements are as much as 1.5cm different from the calculator.
Then when I compare to my 19th Century small-hole flute, it’s a whole different story.
As @david_h points out, your other flute probably has tapered sections of the bore, which your bamboo won’t match. Additionally, it probably has different wall thickness and bore diameter, so a straight copy probably won’t work. Bamboo is very irregular, so I’ve found a purely analytical approach rarely works.
When I make a bamboo flute, my method is to first make the embouchure, then trim the foot of the bore until it plays at the fundamental note I’m looking for.
From there, if I were using using flutomat, I’d adjust the embouchure diameter and/or lip cover % until flutomat predicts the same note I’m getting, for the same length of bore.
This gives the other tone hole locations the best chance at being correct. I then burn out the foot-most hole in the smallest diameter I can, gradually increasing the diameter until the first note matches (let the flute cool down between burning, and blow out any hot air or smoke which will change the pitch).
Once the first hole is close to being in tune in the first octave, I’d check it against the flutomat prediction and see if it’s under-predicting or over-predicting. Whatever error I get is used in adjusting the next hole up the bore.
That looks correct. The numbers in the Cents column point to a diatonic scale from the bottom note as you open the holes, with a B that’s a hair flat of ET.
To be clear, initial measurements are from the CENTRE of the embouchure hole, correct? (Closed end to centre, centre to end of flute)
After that, I assume you work your way up the flute, fine tuning as you go.I would not think it’s like a guitar, where you can start with a rough tuning, and adjust later.
I don’t know if anyone is particularly interested, but I made a bit of a botch on my first attempt at making a bamboo flute. It’s a bit of a comedy of errors, of which I own at least 90%, but my tools and technology definitely played a part in my downfall.
Long story short, (too late, I know) my first cut was sharp, even though I purposely aimed low so as to give myself room for fine tuning. From there, all my calculations were off. Tone hole 6 was flat,(!?) and nothing I could do would bring it up to pitch. I should have quit there, but I wanted to see what I could learn from the experience.
From there on, it was pure guesswork as to what the Flutomat was telling me. I tried to overcompensate, but each pitch remained flat. When I hit hole 5, my Dremel sanding bit said goodbye. (If you’ve never seen a Dremel sanding bit explode into fiery bits, it’s a sight to behold!) I switched to a router bit, but they’re not great handheld.
What can I take away from this? Well, the flute itself has a really nice tone. Though it’s missing some of the more complex harmonics, it’s not nearly as hollow sounding as I expected. The tone holes themselves were easy to drill, if only I could position them correctly.
I’ve got enough bamboo for another attempt or two. (one in D, and another smaller flute)
I’ve also got an order in for some new Dremel bits, so I hope to be back in the shop in the very near future.
The thing that confounds me is that the first (6th) tone hole was flat. As the measurements are from the end of the flute, I thought the holes would have been sharp, or by the happiest of circumstances, IN tune.
I’ll be inputting all new numbers for my next attempt, so hopefully I’ll get more consistent results.
I’m also considering offsetting the 3rd and 6th holes, much as I dislike offset holes. The stretch for a D flute is pretty big even for large hands.
In that position I would first make a trial one in low cost, reproducible PVC tube to get the hole position calculations sorted out. (I am less experienced at the practical side of things than you - I only took delivery of assorted PVC pipes yesterday). I put the measurements of a Generation whistle and a Tipple flute in G into Hans Bracker’s calculator and got sensible (but not identical) results.
One challenge you will face in getting the tuning spot on in a bamboo flute is that the bamboo itself is not uniform. Every piece is slightly different. Specifically, the bore profile of each piece is different, and the bore profile has a big influence on the position of the tone holes. So its a chicken and egg kind of problem.
Flute makers have long known that you can adjust the tuning of a note either by changing its tone hole position or size, or by changing the bore profile, by introducing constrictions or cavities at specific points that are relevant to that frequency (pressure nodes and anti-nodes).
Since the bamboo is not a uniform cylinder, every piece has certain constrictions or cavities built in. One way you could try to reduce the variation is by trying to shape the bore before you start. But to do this well you’d probably also need some way of accurately measuring the bore at various points inside, for example with a set of long handled T-gauges. Unfortunately, the standard ones are not only expensive, but also don’t have handles long enough for single piece flutes.
Another approach is trial and error, where you just accept up front that 90% of the flutes you make will either not have good tuning, or will have to be discarded due to the bore profile not being consistent with the tone hole lattice layout that you are trying to use. And it may be more than 90%.
My process is generally denial and error, so I’m well on the way to making whole families of unsatisfactory flutes.
I have a long-shank 1/2” boring bit for clearing nodes, and it goes a long way towards evening out the bore. To smooth things even more I use a dowel with varying grades of sandpaper furled around the end. When attached to a drill, the centrifugal force polishes the bore, and reduces some of the irregularities. This also gets rid of the downy inner “skin” inside the tube, which to my mind sucks up some of the higher harmonics. (I gave myself a pat on the back for that one.)
That’s what I was trying to do with my first attempt, but it was more guesswork than science. I’m curious as to how far I can adjust the hole size and position to make the spacing more ergonomic while still providing even tonal response in the flute. I imagine it is an exercise in diminishing marginal returns.
I checked this out. I understand that it’s based on Flutomat, but it seems easier to follow. (Except for the window/embouchue entries… I just know I’m going to get those wrong!)
