Frank Gilliland wrote:
On 29 Nov 2007 02:22:22 GMT, Steveo wrote in
:

Frank Gilliland wrote:
On 28 Nov 2007 23:22:25 GMT, Steveo wrote in
:

Jay in the Mojave wrote:
Steveo wrote:

Hey Jay I just picked up an mc-60 cheap for this kenwood, dude
dropped it off for test and tune. It ain't an electro voice or a
heil but i'm getting good audio reports from it at any rate. (i
hit the up/down switch by mistake if i'm not careful) instead of
the key.

Hello Steveo:

Yeah those MC60 mics are good mics. I had one and it sounded like
broadcast quality audio. If you can get our hands on a Sure 444
those also great mic's.


Hi Jay, yeah I've heard those Shure mics on the air and they have a
nice sound too. Microphones are a strange bird, what sounds good on
one radio may sound like crap on another. Heil makes a good sounding
mic too imo. I'm happy with this mc-60 so far..but I'm always looking
for better audio, you know how it goes..

The two things to watch are impedance and output level. You need a mic
with an output impedance that is equal to, or lower than, the input
impedance of the radio. The Shure 444D and some other mics let you
switch between low and high impedance outputs to better match the
radio. As for the mic's output level, if it's fixed then you need to
adjust the mic gain to match the mic. Note that high impedance mics
generally have high output levels, and low impedance mics have low
output levels. So if you want to use a low impedance mic with a radio
that wants a high impedance mic, you may need either an impedance
transformer or a mic pre-amp to get the level high enough for the
radio to use.

Sometimes I don't explain things very well, so if you got lost then
let me know and I'll try to explain it better.

Hello Frank

Yeah you explained it just fine man. I understand the impedance part and
mostly high z with tube rigs and low z with transistor's.

Unfortunately, that's not the case. Tubes are often fed at the cathode
which requires a low impedance mic, and transistor mic preamps are
usually in a common-emitter configuration requiring a high impedance
mic. And -then- it depends on whether the input is run through an
input transformer, converting low-Z to hi-Z or vice-versa. Ya just
gotta read the manual and know the radio.

This mc-60 is
switchable to either but like I said before mics are a strange bird and
will vary from transmitter rig to rig and brand. You never know until
you hear it on the air.

That was the point I was trying to make -- a lot of those variations
are due to differences in impedance and mic output levels. The mic
preamp gain for one radio may have been set for one specific mic,
while the preamp gain for another radio of the same model may have
been set at a different level for a different mic. And sometimes there
are even significant variations between mics that are the same model,
especially with crytal mics. My point being that if you can adjust the
mic's output level and match the impedance to the transmitter, the
sound can be fairly predictable.

BTW, I used to have a setup with a small 4-channel mixer board. Ran
the mic on line 1 and the cassette deck on 2 (never used the other
two). Worked great, I could plug almost any mic I wanted into the
board although it was usually occupied by the Shure 57. Used a foot
switch for keying. Best setup I ever ran. I really should look for
that old mixer board.....

Gotcha that time, Frank. As for me..I'm as close to broadcast quality audio
as I can get so far and that is -not- without experiments with gain and
impedance.

It's like I said last year, I wish you lived down the road from me so you
could keep me on the right track.

I'm still looking at those electro-voices too.

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