So I have a generation that I at first didn’t like because it sound extremely out of tune to me. However, it plays really smooth and easy (though still out of tune) in the second octave and I’ve decided that I kind of like it. I also recently got a Mellow Dog that I love and which is wonderfully in tune (both whistles are D). Thing is, if you line the both up such that the open end of the horn is even and the finger holes match up, the lip of the labium ramp is about 2cm further away from the horn in my generation then in my MD (this is with both heads pushed in as far as they will go). I’m thinking that if I lop 2cm off of the top of my gen tube it might bring it in to tune and make it geometrically similar to the MD, but what I am wondering is does the wide bore of the MD alter it’s length in any way? Is it a good model to use for figuring the length of a whistle of normal bore?
Yes, length and hole placement are based on bore size.
The Waltons Mellow D is pretty wide compared to most
other mass-produced D whistles (which is why Jerry
Freeman can fit a Feadog C head on there).
If you remove any of the tube, it will allow you to push
the head on further and therefore sharpen the tuning.
The result on the relative tuning of the notes is pretty
negligible, but you might see some difference. I’d start
with small changes.
You might also just need to work on breath control to
get each note properly in tune.
I try to allow a little room so the whistle plays in tune with the whistlehead pulled out just slightly.
When I do tweaked generations, I shorten the tube (at the whistlehead end!) 1/8 inch. (I haven’t always done this. It’s one of the details I’ve picked up over time.) I find tweaked Generations play reasonably well in tune with 9 5/16 inches of tube exposed below the whistlehead socket. You can try this as a starting point with an untweaked Generation and adjust from there.
You commented that the Generation’s out of tune in the second register. There’s some player control involved in getting these whistles reasonably on pitch throughout the range.
A good thing to do is set the whistlehead in a position where the difference between registers is averaged across the upper and lower registers. That is to say, get it so that one register is slightly sharp and the other is slightly flat. Then, as you become more accustomed to the whistle and as your ear becomes more attuned, you’ll tend to blow the notes more on pitch by the amount of force you blow each note.
Best wishes,
Jerry
Yikes! 
I just lined up a couple of my stock Generation Ds and my Mellow Dog D, all tuned to A440. And the whistles are all dead even: 265 mm from blade to bell end. That’s 9 5/16 inches (238 mm) of exposed tube on the newest Gen head, exactly as Jerry said. And 9 3/16 inches (234 mm) exposed on the Mellow Dog.
jstomel, if your Gen head is 2 cm too far out, you simply need to push it in 2 cm. No need to start cutting tubes! In its current position, the head is sitting right on the very tip of the tube*. Your Gen will be a semitone flat (Db), and way out of tune with itself. And the head might fall right off if you play it!
- The Gen tube is 260 mm long. Your current position is 238 + 20 = 258 mm of exposed tube. That leaves only 2 mm of contact!
I you were to actually cut 2 cm, the head would end up on the tip of the tube again. Not good! Just push it onto your existing tube until the blade lines up with the Mellow Dog, then use a tuner to check the tuning. Done. 
Just re-reading this:
(this is with both heads pushed in as far as they will go)
This makes no sense to me, unless something has changed drastically in Gen manufacture.
jstomel, pull the head off your Gen D tube and measure just the tube. How long is it?
I’ll do some measurements when I get home, but I thought it was somewhat weird. I assume that the generation manufacturing process is very standardized, but sometimes you never know. Incidentally, my sweetone matches up with my mellow dog to within a few millimeters, both are shorter than the Gen. It sounds out of tune throughout it’s register, but I can force the bottom notes into something like tune with breath control. The top notes of the lower octave are definitely out of whack, though. It falls back into tune with itself in the second octave (it’s not necessarily in tune with D, but it still sounds OK).
Sounds good. We’ll figure it out!
The Gen tube is a smidge under 10.25 inches. The mellow dog is a smidge under 10. With the whistle head attached and seated as far as it will comfortably go in it is 10 13/16 in from the labium ramp to the bell on the Gen. The mellow dog measures 10 1/4 in from the labium to bell. So the gen is a bit over half an inch (about 1.3 cm) longer. The length from the centre of the last key hole to the tip of the bell is 1 8/16 in. on the Gen and 1 10/16 in. on the mellow dog. The length from the labium ramp to the centre of the first key hole is 5 in. exactly on the Gen and 4 11/32 in. on the mellow dog.
Hope that helps.
Oh and my gen has 9 and 10/16 of tube below the whistle head. Despite the tube being only 260mm long. I now think that there may be a problem with how the whistle head fits on. Perhaps it has become warped and will not fit all the way in.
Yes, that is what I’m thinking, too. It may not even be warped. Sometimes Gen heads are pretty tight, so a bit of gentle force is required. Make sure there’s no glue residue inside the head or on the tube. Then try twisting the head down onto the tube firmly but carefully, trying not to wiggle the head sideways, lest you crack the plastic collar. If you need extra traction, wearing a pair of latex kitchen gloves can provide a better grip.
You should be able to push around 2 cm of the tube into the head.
If that works, you can use a bit of lubrication to make future adjustment easier. Cork grease, vaseline, chap-stick all work. Smear some inside the collar and around the end of the tube. You can also sand out the inside of the collar a bit with a fine grade sandpaper (Jerry does this on his tweaked Gens).
With any luck, you’ll end up with a really nice Generation. Let us know how it goes!
After making sure any remaining globs of glue have been scraped off, take some acetone or nail polish remover on a tissue and wipe the end of the tube that goes into the whistlehead. This will remove the lacquer in that area and make the tube fit more easily. I find I have to do this with all Generation tubes to produce an acceptable adjustable fit.
Best wishes,
Jerry
Jerry, that’s only for a lacquered brass Gen, right? Wouldn’t make any difference on a nickel tube. jstomel doesn’t say which one he has.
That’s true. In my experience, it’s usually the brass ones that are too tight. Because the plating doesn’t add any appreciable thickness, the nickel plated tubes usually aren’t problematic. There could be an occasional exception, of course.
Best wishes,
Jerry
My generation is nickle and I tried forcing it on with greater force. It went in about another 1/4 inch or so. I don’t think I could force it further without using tools or banging it against something. But it now is reasonably in tune when I pay careful attention to breath control. I think that I shall widen the bore of the whistle head slightly with sand paper and get some gel to lubricate it. When I get around to it I will probably cut 1/8 to 1/4 inch off the top so that it has some tuning range.
Thanks all for your help
I’ve had to do that with all my Gens (nickel
included). Be really careful when sanding
that you avoid the underside of the ramp.
I’ve just gotten the head to slide nicely
and suddenly realized I’ve ruined the ramp
from underneath.
Good advice, fearf.
With Gen heads, there sometimes seems to be a “stopping point” short of full insertion beyond which it doesn’t want to go. But if you work on twisting it past that point, it will eventually give way. And once you work the tube into the head a few times, it gets easier.
Again, be careful not to crack the collar. I’ve seen quite a few whistles with electrician’s tape around the bottom of the head - including one of mine. Oops. 