A long time ago I got a Susato D/C set, one head, two barrels. As a C whistle, it plays beautifully and sounds great. I feel no need, or temptation even, to get another C whistle. But as a D whistle, it has a raspy sound that sucks. So the difference must be in the barrels, right? Any thoughts or explanations?
Air leak perhaps? I’d try taping the joint with electrician tape to see if that makes a difference.
I don’t think electrician tape would be my first line of action. Those whistles should have come with a tube of joint grease. If you haven’t lost it or tossed it, slather some on the joint. While you have it apart, check the o-ring. If it’s broken or missing, that would affect your seal, too.
There is an optimal ratio of diameter to bore length. The Susato C is closer to it than the SB D.
even still, a normal susato D shouldn’t sound like raspy poo.