Vixen I think you have just been very lucky with your whistles. I too have played the woodwind instruments you have mentioned for many years (therefore have good breath control).. and consider myself to be a very good whistler (oh dear... that doesn't sound awfully modest.. ah well *grin*)... and I just can't use them although I have used a low A for playing slow airs that stay mainly in the low register (sounds great)..... but I wouldn't trust a D for a fast jig or a reel..

However... my theory about the problem is that I play the whistle out of the side of my mouth.... the susato mouthpiece is too short for that... but even straight out (like a recorder)doesn't work.... do you play yours to the front or the side? just curious...

slainte

alison