I also tried several mics and use the TT 705. I
bought a demo unit from Ten Tec.
I understand the Heil is coming out with a
modification to their mic to enhance its performance
with the Ten Tecs.
The problem with evaluating microphones is the
subjectivity of listening to a transmission and the
misconception that many hams have of what a signal on
single sideband should sound like.
In order to keep a narrow 2-3K bandwidth most Ham
radio manufacturers design their microphones and audio
input circuits to roll off the response below lets say
600hz and above 3000 hz. Most mics have a relatively
flat response in the range of the human voice within
the rolloff. The D-104 is one exception to this rule.
If you look at the response curve of a D-104 it has a
curve that gives low response from about 600 up to
about 1700 hz then flattens out in the upper range
beyond 4000Hz. This is because the D-104 ever since
the CB craze of the seventies, has been and is
designed for CITIZENS BAND radios which use AM not FM.
However many hams feel the D-104 sounds good on SSB.
SSB is not supposed to sound like an AM broadcast. It
is supposed to allow voice communications within the
narrowest bandwidth possible to conserve power and
spectrum. So a microphone that uses as little
bandwidth as possible to allow intelligable
communications is the goal manufacturers shoot for.
Hiel's philosophy is a little different. They offer a
couple of different plug in elements that have two
different frequency responses, one intended for
ragchewing and the other for DXing. Hiel's DX
cartridge peaks up the higher frequencies to give a
crisper sound to the human voice that is supposed to
help in breaking into a pileup by actually making your
voice harsh. The purpose is to penetrate the pileup
and get you noticed. The H-4 is flatter with more mid
frequency response and sounds like a normal and
pleasant SSB voice signal. So Hiel recognizes that
there are advantages to playing with the frequency
response curve for different effects.
So every one of us has a feel for what we consider
good audio and that feel is very subjective. When
evaluating someone's audio consider the goal of single
sideband transmissions, Intelligble Communication in
the narrow bandwidth available to SSB. So if the voice
is clear, not mushy, not breaking up, not distorted
and you understand what is being said then the
microphone is doing its job. Its not supposed to sound
like an AM broadcast or an FM deejay. That defeats the
goal of SSB. To include the full range of human speech
would require a bandwidth from 300 hz to about 7000
Hz. This would waste spectrum and its not necessary
for intelligble communications.
Now another observation I have made is that microphone
choice is especially critical if you are a female ham
(YL). The female voice is on average a full 800 to
1000 hz higher than the average male voice. This
presents a problem if the microphone has a low
response on the low end and boosts the high end of the
curve. If you are a YL or you share your rig with a YL
you may need to evaluate another microphone that has
better low to midrange performance and rolls off the
high frequency better.
OK class, the Lecture's over your reading assignment
is to go to Hiel's websight and read all about
microphone characteristics. For homework tonight I
want you to QSO with some hams and jot down what you
like and don't like about their audio signal. Then ask
them what microphone they are using. We will meet
again next week and compare notes. Maybe we'll all
learn something new about microphones. CLASS
Just as a Postscript I used to have a bookmark for a
company that will take your D-104 and for $125.00 make
it sound like a real ham radio microphone. I heard one
of them on the air and it sounded sweet. If I find
them again I'll post it.
--- firstname.lastname@example.org wrote:
> Mike R. wrote:
> Everyone tells me to try the TT705
> > mic on it (Omni VI+).
> Also heard that Astatic D-104's are popular with
> the TTers, but I
> > experience a RF problem in the D-104 (common
> Hope this helps. I'm satisfied with the TT705 as
> my basic desk mic
> on the Omni 6+. It seems to do everything well.
> Price is reasonable.
> FAQ on WWW:
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