I have trained Tessa on the whistle, using the T.E. Scott dual whistle (one end beadless, one end beaded). I really needed a second one so I ordered it through Gun Dog Supply - looks identical but I noticed that the tone is definitely different - not quite as sharp, and the thrill from the beaded end is not as "thrilling" as the one I have.
How will that affect her response to it? Does it matter what whistle you use once the dog is trained to it?
I know some people have mentioned that during hunt tests or trials a dog may get confused with all the whistles going, but I never had that problem with her, and I should think that a dog's sense of hearing is able, to some extent, to distinguish between the different whistles and pick out theirs. Or do they tune in to the actual command (how it's whistled, how many blows, length, etc)? Or both?