TromboneChat

Has anyone ever used a Greg Black 6C? If so how does it compare to bach 6 1/2

Did you mean Bach 6.75 aka 6 3/4C? I think the Greg Black 7C is more in line with a Bach 6 3/4C in terms of rim size. Note that a regular weight GB is heavier than a Bach by a fair bit.

I had a GB small shank 5c and it was just a weird piece, it didn’t really feel like it did anything that well, and I lost the typical small bore sound. The rim was also uncomfortable for me too, from memory (as was the GB 7c). 6c may be different and the main difference with a 6.5AL is the AL has a much deeper cup and more open throat/blow.

If you’re wanting to experiment with wider rims on shallower cups, I’d highly recommend Doug Elliot mouthpieces, where you’ll have much greater control over rim/cup/shank.

^Most people use a 5C for alto. I believe it was designed for one.