After thinking about this for a few minutes I'll take back my recommendation of the W2IHY box and here is why.
On several amateur radios I've interfaced some fairly expensive condenser recording mics from Groove Tubes, a Heil PR
-40, Shure SM-58, an expensive ribbon mic and some other mics I can't remember using a W2IHY box, some outboard recording mic preamps, compressor/limiters, etc. I also used a high quality receiver with wide IF for setup and a recording engineer friend who knows my voice and was patient enough to tweak everything in.
Depending on who I was talking to and what kind of radio they had I got lots of different comments ranging from fantastic to way too bassy if they had a narrow receive filter that did not allow the high frequency content to pass through their radio. Its interesting the well known late night radio host Art Bell commented on my radio sound and said I had finally arrived, which was a nice complement.
In the end, a stock Shure 526T amplified CB microphone with no outboard gear got the most consistent complements from everyone. You can spend a lot of money and time and probably learn a lot about audio equipment setup but I would recommend buying a Shure 526T and be done with it. They also sound exactly the same on every radio and I have used them on probably a dozen or more HF radios.
Originally Posted by prcguy
Stock CB mics usually have a lot of mid range peak and an SM57 will sound very bland without some equalization. A Shure SM57 is fairly flat across much of the voice range with a little rise above 2Kc and a peak around 6Kc, which will not be heard on many if any CBs..
Probably the easiest way to make it sound good on a CB is a W2IHY equalizer which is designed to interface with radios and is not very prone to RFI. Do a search on eBay, the 8 band version can sometimes be had for about $75.