I’m trying to learn “Mairseail Ri Laoise” out of the “Ireland’s Best Slow Airs” book, but it has a low C which sort of rules out playing it straight on my D whistle. I’m trying it on my C whistle, for which I don’t have a fingering chart, and I can’t seem to figure out how to get this C-natural that keeps coming up. Should I just go back to my D whistle and fudge the low C, or forget about it and take up the fiddle??
Try playing it in the key of G positioning.
Then you can go out and get an A whistle and play it as written.
Laura
My suggestion would be to stick with the D whistle and replace the C-nat with either the (high) c-nat, a D, or a G. Give it a try to see which you like best.
If you switch to C whistle you’re going to have to half-hole the F#, which is a bit of a nuisance.
And by the way, there are no “idiot beginner questions”, only “idiot beginners who don’t ask questions.”
That would be a perfect excuse, er, reason to pick up yet another whistle, wouldn’t it? Someday I’m gonna have to quit buying 'em and really learn to play… 
Thanks, Bloomfield. I’m sure I’ll have bunches of non-idiot questions as I progress. I found that half-holing that F# is, indeed, a nuisance; especially when trying to put that ornament in at the same time. First learn to walk, eh?
At least one person on this board has one of the Overton “modal” whistles that will let you hit the low C. And one fellow has made a D whistle that will play the low C. Do a search of the board for the messages.
-Patrick
Silkstone also has a new modal D whistle that’ll play the low C note..i was --><-- this close to picking one up.
Greg
Learning the song and then transposing it to G as has been suggested isn’t a bad idea. All those C naturals in the song then become F naturals which have to be played by half holing but at least the song then falls within the range of the whistle. F natural is a good note to learn anyway because it does occur in Irish music and you have a nice song to practice it with! Another possibility would be to leave it in D and replace those low e,c,e notes with a roll on e, which might be a lot simpler!
Best wishes, Tom