Bill, NY9H wrote:
a $1.59 electret mic element from radio shack works GREAT with all my icoms and my K2s and K3. ----------------------------------- Yes, those Radio Shack electret elements are excellent. I have one mounted in an scavenged hand-held mic housing that works FB. The element has a very wide frequency response, since it's designed for general purpose audio work, but that's not a problem with modern rigs with filters such as the K2 or K3. Back in the "old days" of vacuum tube A.M. rigs, the modulators tended to "broad as a barn", passing all audio put into them with only minimal shaping provided by the values used for coupling and bypass capacitors in the speech amplifier stages. There were some microphones produced for the "communications" market back then such as the famous Astatic D-104 which had a microphone element with a shaped response showing a distinct hump around 3 kHz, rolling off slowly at lower frequencies and somewhat faster at higher frequencies. That hump helped with "articulation" by emphasizing the mid-range speech frequencies. Astatic even published a frequency response chart showing exactly what it looked like, but back in those days most microphone element manufacturers provided frequency response charts with their various mics. I don't know if anyone is doing that today for mainstream communications microphones. Even the "high end" Ham mics only offer general and uninformative comments about "shaping" and "clarity" that say much and convey little. Interestingly, one of the big exceptions is the inexpensive little Radio Shack electret element. It comes with a frequency response chart showing a very flat response across the audio spectrum. But all is not lost: the SSB filters in modern rigs prevent excessive audio band passes and the K3 goes farther yet, offering a transmit equalizer with which one can shape the audio response to suit one's voice. When doing that, it's good to start with a wide range "flat" microphone element response like the Radio Shack electret. I rather expect, although they don't say as far as I can see, the "high end" Ham mic manufacturers are using elements with a flat response and perhaps doing some sort of shaping in design of the enclosure. If so, then choosing a Ham mic today is really a matter of cosmetics: choosing what looks "nice". Another list member here asked what, exactly, is the best response to provide the best intelligibility under all conditions and how can that be seen unambiguously on a display like spectrogram? That's a good question. Sometimes we get too many choices. I'm happy to record my rig using a wide-band auxiliary receiver and adjust the equalizer for a sound that I'd like to hear from the other end in a rag chew. But then I don't spend long hours yelling into the mic in a contest or trying to shout down the others in a DX pileup ;-) Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
