Though I have not tried the 58A yet, the CM-311-A is equal to the Sennheiser 855e and the SM58. As for the Shure 54 headset mic, I have only talked with someone that had one, and he said he wished he had purchased the CM-311-A instead.

Good Luck,

Gary
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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!

K+E=W (Knowledge Plus Experience = Wisdom.)