[Elecraft] mics

[Charles Harpole]

Ron.... about the time when the famous D-104 was in every shack.... with a vy wide and rather flat response... Astatic also sold a    10-C  (ceramic) and the 10-D (dynamic) elements/mics that were shaped for voice with a peak in the mid VOICE range.  I still have my 10-C and the Astatic paper showing its response curve.  Altho much loved, the "lolypop" D-104 is notoriously broad and flat and is not much good as a communications mic.  To enlarge ur info on mics, please consult Bob Heil's info on his mics that are real communications mics.  The MC-50 generation of mics were not so good.  73, Charles Harpolek4vud at hotmail.com > From: ron at cobi.biz> To: elecraft at mailman.qth.net> Subject: RE: [Elecraft] electronic product standards> Date: Wed, 13 Feb 2008 12:12:55 -0800> > 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 at 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