For all you flute makers... Emouchure hole location?

justbarak · Post by **justbarak** » Wed Sep 10, 2003 8:39 pm

I'm refining my flute making techniques, and I suppose the bane of every flute maker's existence is octave tuning (among other banes). Typically I get fairly good tuning all the way up until the top two holes and the all holes open note (C# on a D instrument), and they become flatter than all get out, the C# especially. Smaller embouchure size and larger finger holes helps alleviate this, as does a conical bore if you are that fancy which I am not (yet). However, the embouchure distance from the stopper (closed end of the flute) also effects octave tuning. Is there a particular direction that sharpens or flattens, or is it erratic? I believe it affects pitch as well. Since I'm using bamboo at this point I don't really have an easy way to experiment with these variables reliably.

Any other tips for improving octave tuning?

Also a general question - how to instrument/flute/whistemaker's start out? School or formal training, reading lots of books, talking to flute makers... I'm sure all of the above, but what is normal? How guarded are professional flute maker's of their 'secrets.' Do they ever apprentice?

Thanks
Barak

Jayhawk · Post by **Jayhawk** » Thu Sep 11, 2003 5:29 am

I've not made a bamboo flute in nearly a year now, but basically the further the emb. hole is from the end of the flute (the closed end) the flatter the higher notes will be and the nearer the emb. hole to the closed end of the flute the higher the higher octave will be. Optimal distance is about one bore diameter from the middle of the embouchure hole to the back end of the flute or the cork.

BTW - check out your local harware store. Mine has a good selection of cork pieces and I often would leave the end of the flute longer and use cork instead of precisely figuring out how to use the node of the bamboo as the end. After all, wooden flute makers COULD decide to leave the end section of the wood and not bore all the way through, but they don't and I don't see why a bamboo flute maker can't use a cork just like a wooden flute maker does.

Eric

justbarak · Post by **justbarak** » Thu Sep 11, 2003 1:22 pm

Sweet - I just took a flute I'd recently finished except that the top two notes of the second register were rather flat, and stuffed a 1mm wad of tissue dampened with a bit of oil into the closed end, and voila - it's in tune. Is still have to roll out a tad, but even on my Olwell bamboo I have to roll out on the 2nd register all-holes-open note.

So what is the difference between a whistle and a flute in regards to the stopper/plug. For a whistle, the plug is right at the edge of the "embouchure" hole, whereas for a flute it is a small distance back. Why doesn't a flute stopper just automatically stop right at the edge of the embouchure. Though the plug in Irish whistle stops at the window, native american flutes (whistles technically) don't [always]. Any explainations?

Barak

"He who joyfully marches in rank and file has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would suffice."
-Albert Einstein

Jayhawk · Post by **Jayhawk** » Thu Sep 11, 2003 1:41 pm

I'm clueless why there's a difference...but I'm sure a much more theoritical person than myself probably knows the answer. I do know on fife's you generally set the cork right up against the embouchure hole - does that confuse things enough for you?

I'm glad your flute is in tune now. I think you always have to roll out a bit on the second octave unless your piece of bamboo is really more conical than cylindrical (some pieces are a tad more conical). Bamboo is great for flutes, and luckily for me it's dirt cheap so I can screw up lots of times before I make one I like and all I've really wasted is about $2 and my time.

Eric

selkie · Post by **selkie** » Tue Sep 16, 2003 10:23 am

Seeing your comment that bamboo is cheap has set me off again on thinking about using a piece of Bamboo to slot onto the end of the mouthpiece to extend it to go to my left shoulder. I'm now using a bicyle pump short tube on foam. I'll be off to the garden centre tomorrow.

Thomas-Hastay · Post by **Thomas-Hastay** » Tue Sep 16, 2003 2:08 pm

The formula for calculating the "compromise" position of the cork for good matching between the 1st and 2nd registers is

<b>7 (D/6) where,
D = The bore diameter at the embouchure.</b>

Seven times the product of the Diameter divided by 6 will give the distance between the center of the embouchure hole and the plug face. Moving the plug closer to the embouchure will favor the 1st (low)register. Moving it away will favor the 2nd (high)register. The reason for this is a phase-shift(flatter)in the second register due to increased air column velocity.

Cylindrical Whistles do not have a tunable cavity above the embouchure so they must correct the exponential phase shift by embouchure bending(blowing harder to sharpen)in the 2nd, 3rd and 4th registers. The 4th is the most flat.

Recorders compensate for a lack of a tuned cavity to match registers by using a precisely tuned(angled)conical bore. The conical bore's "backpressure" at the higher velocity 2nd register, slows down the air column just enough to correct most of the phase shift. The "drawback" of a conical bore is limitation to only 2 registers with difficult notes at the top of the scale(ergo Recorder weakness).

I recommend reading Lew Paxton Price's "Secrets of the Flute" and Bart Hopkin's "Air Columns and Toneholes" books. You can find them in the "craft manuals" area at...
http://www.shakuhachi.com/TOC-CM.html