Right; you cannot get 16kc's out of 2.8kc's. Many radios aren't that narrow, as 6db/octave filters aren't all that steep and the real width is often 3.3-3.5kc's. But you can get more out of the available bandwidth you do have by using better audio gear. And FWIW, Heil's best mic for audio quality is the PR-40. The rest are just so-so. You won't find too many of their mics in any studio or live application with the exception of the PR-40.
What W8JI says, I don't know and therefore cannot say. I'll match my audio background in what he does with his Ham background though. Studied in school/studio and have done live sound for the pro's.
The human ear gets 90% of its info from 100hz to 4khz range. So, making the best of the available range can be done easily if one knows how. Not that hard to do and can be done by any radio operator. Mic sensitivity/db change with freq/overall freq response can make a vast difference when picking a mic.
Pivotal.
For that reason, large capsule condenser mics are best. Since Eastside is a musician, the chance of him owning a Shure SM-58 are fairly high. He can use that mic and do much better than the Heil he has - IMO. Might not be the best choice, but a very nice choice all the same.
Perhaps you should listen to a eSSB radio that is TXing just 4kc's wide if you haven't already. Mind blowing for a Ham radio. Or CB for that matter. I think there is resentment and resistance in the Ham community to new things - even modest ones such as audio improvements. For a hobby built upon the principle of growth and learning/using new things, at times it is anything but. There is no harm done whatsoever to running 4kc's wide. Ridiculous.
As far as Eastside's mic cable, I would have to say that the 4 wire plug to his mic can be rewired to a 3 pin plug. The extra wire for the 4 pin plug/mic is to allow for the +8v from a Ham radio to power the electret mic element (a kind of condenser element). That's a guess; but a fair one. So, one of the radio/plug wires is to feed this voltage to this element. Eastside will either need to re-wire his existing cable, or sell it and the mic to someone and get another cable. Since he doesn't get involved in soldering and wants everything 'plug and play' he may need to start over. Or just keep what he has until he is ready to go for it.
