Re: Slightly OT
Putting an SM58 screen on a Beta57A essentially gives you a Beta58A. As mentioned already in the thread, the on-axis response may be the same, but the off-axis will be different (narrower at high frequencies for the 57), which helps with the singing drummer problem.
I have a number of old Beta57s (not the A version) with 58 grills, and I don't hear a significant difference between the modified B57s and the real B58s. On the parts list, the two capsules have different numbers, but physically, they appear to be identical. I do hear a difference between the B58s and B58As however. Unfortunately, original Betas are made of unobtainium, so I've been modifying old 57s to add to my stock.
One other factor that may be worthy of noting: You may find that Beta grills cost considerably more than the SM version. It's not just the blue rubber band you're paying for, they are significantly more resistant to denting.
GTD
