**TIME STAMPS IN THE COMMENTS**
I took a break from my studies to do a comparison of the entire Chieftain Thunderbird whistle lineup, with my other model whistles, so you can get an idea of how they sound relative to one another. Each has its own character.
Soprano D/C - Robust whistles with low-whistle character, but are harder to control, and certainly loud. I played the D at my session, when things got loud, and you could definitely hear it, though it doesn't seem to blend. If I wanted to lead some tunes, I might use it so I could be heard over the din.
Bb - Want a Bb that is stronger than a Generation, but still sounds nice? This is that Bb.
A - Surprisingly mellow, you can't lean into it like the Bb, but it's got a nice tonal characteristic. **Update** Someone asked me about playability of this one verses the MK, saying they struggled with the Chieftain. I think the primary reason for this, aside from the sensitive breath requirements, is that the Chieftain has some massive holes, particularly L2 and R2 (OXOOOO and OOOOXO). I found that my fingers weren't always covering them. Switching from the piper's grip to playing with the pads of my fingers helped, but I ended up sanding the largest holes (simulating years of play wearing slight finger depressions into the metal. I think Phil Hardy calls them "scalloped" on his V5. It's been helpful, though it still takes some getting used to, and if you have very thin fingers (mine are long and slender), it might be better to get another make.
G - This is an alto G that really plays like a low whistle. Full, complex tone, kind of fuzzy, but really nice. I think this reminds me of the Reviol with the G body, but it backs off the power just a bit, in exchange for more haunting goodness. I'd agree with Phil Hardy when he asserts that it's one of the best alto Gs on the market, especially if you're looking for low whistle character in a G.
F - Needs a more delicate touch than the G. Less robust, but very smooth and lovely when you settle into the breath requirements. This is a lullaby whistle. Beautiful and smooth.
D - For some reason, I think of a French horn with this whistle. Kind of a nasally, but muted quality. There's some complexity, like the MK has, but also a muffled, smoothed sound, like the Goldie. I haven't quite gotten the hang of this one. It takes more force to push into the second octave.