I have never had a D-104M6B mic before. I have and do have D-104 desk mics. I would like to know what some of you think about the D-104M6B mic. I hope i did the right thing, because i went ahead and order a new one to go on my Cherokee Nightrider or my Uniden Grant. I do know for a fact that the Astatic AST-878DM is a great sounding mic. I bought me a new 2950DX and i went ahead and got the Astatic AST-878DM mic also. I have had nothing but great reports on how loud and clear it is. My silver eagle i just put up and i am only running my Astatic AST-878DM. So if anyone is looking for a good desk my get the Astatic AST-878DM, You will be glad you did.