Flute-O-Matic Problem (Solved)

[raindog1970]

Would any of the more experienced whistle makers please take a look at this screen capture from the Flute-O-Matic Hole Position Calculator, and tell me why my bell note would be flat in both octaves using this formula, while every other note is almost perfectly in tune?
I have to cut 1/8" off the bottom end of the tube to bring the bell into tune with the rest of the 1st octave scale... but doing so ruins the tuning of the 2nd octave.
No amount of tinkering with the Flute-O-Matic has produced a single tube that doesn't have a flat bell note... and I'm using a milling machine with digital read-outs to cut the finger holes, so the error isn't occurring there.
I'm also disregarding the bit about the embouchure diameter and the calculated distance from the end of the flute, as has been recommended in past discussions about the Flute-O-Matic.
Any advice would be greatly appreciated... I'd like to keep the little bit of sanity I still have left!

[AngeloMeola]

When I use the flute-o-matic, I consider the tube length an approximation. I keep trimming until the note is right. Then I measure the hole placement from the trimmed end using the calculated distance.

I have only made a few whistles, but this method seems to get the holes in the right places.

[raindog1970]

When I use the flute-o-matic, I consider the tube length an approximation. I keep trimming until the note is right. Then I measure the hole placement from the trimmed end using the calculated distance.

That's the same approach I'm taking, but I'm still ending up with a flat bell note on every tube I make... there must be some simple little thing that I'm overlooking, but I can't figure it out.
My understanding is that you should never need to trim from the bell end after using the Flute-O-Matic to calculate the hole positions, and experience has showed me that doing so to correct a flat bell note will throw the rest of the scale out of tune.

[brewerpaul]

Somewhere on the Fluteomat site, there is an e-mail address for PeteKosel who wrote the program. Ask him about your problem-- he's pretty good about answering.

[JessieK]

You have to start with an in-tune flute or whistle. It may say the size of an embouchure hole, but that may not be accurate, Do an embouchure hole the way you see fit and THEN check the note that comes out. When you get it to be the bell note you want, or just a touch flat (if the tune is thick, the depth of the holes will make it sharper), THEN apply the hole sizes and locations.

~Jessie

[raindog1970]

You have to start with an in-tune flute or whistle. When you get it to be the bell note you want, THEN apply the hole sizes and locations.

Right... put a mouthpiece on the tube, then cut it to the proper length to play the desired bell note, then cut the finger holes according to the output of the Flute-O-Matic.
But all the notes produced by opening finger holes end up too sharp, and trying to compensate by opening up the tuning slide and shortening the bell end ruins the tuning of the upper notes... it's a no win situation.
The strangest thing is that every note besides the bell note in both octaves come almost perfectly in tune if I just close the tuning slide a bit... even OXXOOO C-Natural comes out right.
I'm not smart enough to figure it out on my own, but hopefully someone will set me straight before I go completely insane!

[JessieK]

Odd. I've always had luck with it. While I have experimented with various hole sizes and locations for an in-tune cross-fingered C natural, when I have ignored whatever flute-o-matic says for embouchure hole size and have followed the procedure I mentioned, it has always worked. Again, try to cut it a little flat, so that the resultant sharpening (because of the depth of the holes) will bring it into tune. Good luck.

[serpent]

What Jessie says regarding the method of final hole placement is pure gospel, and works on all my whistles, but there is one thing that is very important - be sure that your window surface area is the same as the area of the embouchure hole shown in the calculator. If you don't do this, you will wind up with either the situation you describe, or with a Cnat that won't work properly when crossfingered oxxooo
Example:
A 3/8" (0.375") diameter embouchure hole has an area of 0.110 sq. in
A rectangular window 0.475" by 0.25" has an area of 0.119 sq in.
The rectangular window calculates out to an embouchure hole diameter of 0.3888, or just a bit over 3/8".

The dimensions I've just given match those of the Serpent Python, and the calculations work perfectly re. full-scale tuning on that instrument. However, if you use the same embouchure hole in your calculator on a high D whistle such as the Viper, where the window is 0.25" by 0.27", the calculated equivalent diameter is only 0.293", or about 9/32. When I use the 3/8" embouchure in my calcs, I get exactly the same resultant pitch sharpness going up the scale.

Conclusion: Calculate the equivalent embouchure hole diameter for the Flutomat to match the area of the window you're using. It's easy on any calculator that has pi and square root.
2(sqrt((Length X Width) / pi)) gives it to you in decimal, which you then plug into the Flutomat embouchure number.

The next mystery, of course, is that of hole diameters - both absolute, and relative to position on the tube. That is almost a black art, and all I've managed to do so far is come up with a few rules-of-thumb, rather than calculated ratios. These absolute diameters and ratios, are needed to maintaining desired temper, and (especially) to give proper tuning on crossfingerings, with special emphasis on OXXOOO.

I leave that particular mystery to the ingenuity of the readers. Let me know if anyone puts some science behind it. I sign off now, knowing that I have thoroughly bored some, thoroughly confused others, and had a few lightbulbs appear above a few heads!
Cheers,
serpent

[raindog1970]

be sure that your window surface area is the same as the area of the embouchure hole shown in the calculator. If you don't do this, you will wind up with either the situation you describe, or with a Cnat that won't work properly when crossfingered oxxooo

OK, but changing the embouchure diameter only changes its calculated distance from the end of the tube... it doesn't change any of the finger hole positions no matter how large or how small you tell Flute-O-Matic it is.
I'm using 1/2" CPVC pipe with a tuning slide made into it similar to that of a Water Weasel, so I can adjust the overall length enough to get the bell note in tune... as long as my tube isn't too long or too short for the tuning slide's range of movement to compensate for it.
I've also checked to make sure that the inside diameter and wall thickness are both correct, and they are.
I'm afraid that I'm still as much in the dark as ever, but surely the light bulb will eventually come on!

[serpent]

Every hole in the whistle has an effect on tuning, including the embouchure, or, window, if you will. The chimney diameter and height affects the effective length (and to a smaller degree, the diameter) of the tube. CPVC tubing is typically thick, 0.070" or greater, so this effect is much more pronounced than in tubes with thinner walls. I had the exact same problem as you, with my prototype Serpent Polly whistles, until I remembered to factor in the windway. The problem immediately vanished.

Chamfering the underside of the finger holes helps, too, esp. on thick tubes. The Coanda Effect increases the velocity of the air escaping from those holes when they're chamfered. There was a lengthy discussion of this a few months back; might be worth a look-up and read.

More than any other thing you can do, though, that will make a difference, is to experiment! Make a head that works, and play with a bunch of bodies.

A question: Are you machining in a slide, as I do with the Viper and Polly, or are you inserting brass or other tubing as a slide? If the former, how thick is the wall of the male part of the slide. If the latter, how thick of tubing are you using? Or are your slides external? Remember, as you change the base tuning of your whistle, you also have a longer or shorter length of varying-size tubing to contend with!

Whistlesmithing isn't rocket science, but some bits of it are real close!
Cheers, best of luck to yer!
serpent

[Jerry Freeman]

Serpent,

Please explain what you mean by "factor in the windway."

Best wishes,
Jerry

[raindog1970]

I feel really stupid now, but I finally figured out that the tuning problem was with me, and not Flute-O-Matic... although that should come as no surprise to those who know me!
My whistles have very low breath requirements, which is intentional on my part because I don't have the greatest set of lungs in the world.
I was simply blowing the whistle out of tune... even I am surprised at how little breath my whistles require!
I made a tube from thin-walled brass earlier today to see if somehow the thickness of the PVC was throwing off Flute-O-Matic's calculations, and it worked perfectly... but it was the wider bore that did the trick, since that made it require a bit more breath pressure.
After tuning the PVC whistle to the proper 587.33.33Hz with all holes covered, I just decreased my breath pressure and it came perfectly into tune!
I've played along with several recordings, and no longer detect any tuning problems... maybe I'll actually be able to get some sleep tonight since that issue is no longer gnawing at my brain!
Bear with me fellow whistlers, I'll get all my ducks in a row eventually!

[Daniel_Bingamon]

You may notice on thick bored wood instruments that the upper toneholes tend to go out of tune - the area created by tuning coupler can play havoc with it.

[Jerry Freeman]

the area created by tuning coupler

If you don't mind, could you also explain what that means?

Thanks!
Jerry

[Daniel_Bingamon]

When you you have a socket/tenon tuning coupler made of wood, as the coupler opens up, the void created by the thick tenon being moved out creates an area increase much like a tonehole chimney. PVC whistles also experience this.