I have a brass Burke high D session whistle and love it. Now I’m going to purchase a narrow bore high D and want to know the difference to expect in brass vs aluminum whistles. I’m not sure which to order. (I’ve tried emailing the Burke Whistles site, but haven’t gotten a response as of yet.) Any observations, comments, preferences, or biases that will help me make up my mind will be appreciated.
Thanks.
This video from Doc Jones might help:
http://www.youtube.com/watch?v=D_P9GYVKNqQ&feature=channel_page
Jason
It’s subjective and impressionistic (and synaesthetic) IMO. Some think that brass gives a mellower sound than aluminum or nickel, but I never hear a consistent difference. Geometry is far more important than the material. So it’s mostly your preference for the look and feel of the metal and how it ages (or not) over time.
And welcome to the Chiffboard. 
Doc’s video linked above pretty much demonstrates my impressions from playing them. All Burkes are pure, the aluminum whistles have a sweeter sound, brass a bit warm and complex compared to the aluminum, and the composite material does sound and feel more like wood than metal.
I’ve had all three, The one I kept longest was the brass. It met my personal preference by a small margin more than the others. Altogether very nice instruments.
But preference is subjective and personal as MTGuru asserts. Have fun.
I own and play all three - aluminum, brass and composite. And I agree with the previous posts. It may be a matter of how much you want your whistle to weigh. The composite whistle is so light you may forget to hold onto it. The brass whistle feels substantial, you know it’s there. The aluminum whistle is in between those two. The all sound good and have the same playing characteristics. I’ve recorded with all three and the brass and aluminum are indistinguishable from each other in a mix (although I feel a difference when playing them). The composite whistle is just more mellow. You can’t make a bad decision here.
I’ve offered this opinion before, it’s merely one opinion though. If I had to live with just one whistle (shudder!), I’d probably choose the Burke narrow bore brass. And yet I play the heck out of the aluminum one too. Buy all three just to make sure.
Feadoggie
I want to thank you folks for the thoughtful responses to my question. Still not sure, but like you said, I can’t go wrong either way.
I own a brass Burke high D session.
It’s not a narrow bore, but I can tell you what a pain it is to polish it as it always tarnishes.
I assume that aluminium still tarnishes, but unlike brass which results in a matt finish aluminium will still retain some lustre. Am I right, aluminium whistle owners?
Yes. If you’re a shiny whistle fan (like me) … With its gloss finish, the aluminum Burke will show some wear at the fingerholes and thumbs, which can be more or less polished out. Otherwise it retains its shiny appearance with only very occasional polishing.
How shiny are you? 
oh, he’s very shiny!
and he’s got three speeds!!!
But the wheels fell off a long time ago … 
I’m a shiny whistle fan too i was really leaning towards the brass, but then, i remembered how brass tends to develop patina really fast (especially when i’m living near the equator, with crazy high humidity), and i want my whistle to still have that shine with little effort. i wonder though, what makes brass that much more prone to tarnishing than aluminium?
Aluminium oxidises way faster than the metals in the brass alloy (copper and zinc), but aluminium oxide forms a thin hard, almost invisible, layer. The patina on brass is much darker and therefore much more noticeable. I think the patina on brass is more porous, and so becomes thicker before it throttles the corrosion.
I like patina. I’ve also always liked carbon steel knives that developed a nice patina over time.
When you polish, aren’t you removing a microscopic amount of metal? Over a couple of decades, you’ll polish your whistle away! 
after a couple centuries, yes! 
ack!!! ya’s got new wheels!!!