First, I don't think any Heil mic ought to be taken as a standard. I
view Heil as most audio professionals view Bose -- "better sound through
advertising."
Second, the SM58 is a single-D cardioid, and Shure's published data is
for the mic at considerable distance from the sound source. When used
close to a sound source, there is a LOT of bass boost as a result of
proximity effect, so the "close-talked" response requires a lot more
low-cut EQ.
Third, My standard recommended starting point for TXEQ for ALL mics is
max cut of the three lowest bands, 6dB cut of the 4th (400 Hz) band.
Some mics, including the Shure 444 and some Heil mics have an
intentional boost around 3 kHz to compensate for the rolloff of SSB
transmitting filters, and I view this as a GOOD thing. For mics that
lack this boost, or have have the boost at a much higher frequency (the
SM58 has a boost around 8 kHz), I recommend a boost of 3-6 dB in the top
two bands. All other bands should be set "flat" (no boost, no cut).
After making these settings, adjust COMP to see about an indicated 10 dB
of gain reduction on voice peaks, then get signal reports from a good
listener. These settings are for maximum talk power, NOT for high
futility, and if done right, will multiply your effective power by about
20 (13 dB). That will make you easier to copy on the other end, which,
for me, also makes casual QSOs and ragchews easier on the ears when
you're not booming in on the other end.
73, Jim K9YC
On 10/10/2018 11:07 AM, Joe Subich, W4TV wrote:
If one has a flat "wide band" mic (electret) the typical TX EQ settings
needed to emulate the Heil HC4 (DX)/HC5 elements, a couple classic
"communications" mics and a typical dynamic "vocal" mic (SM58) are:
-- SHURE --
HC4 HC5 D-104 444 SM58
50 -16 -16 -16 -16 -8
100 -16 -16 -10 -16 -2
200 -16 -3 -4 -7 0
400 -4 -2 -3 -2 -1
800 -0 -2 -1 0 -1
1600 +5 +2 +3 +3 +0
2400 +10 +5 +9 +7 +1
3200 +10 +6 +13 +12 +4
Thanks to: <https://owenduffy.net/audio/legend/index.htm> for the
HC4/HC5/D-104/444 response curves. The SM58 data comes from
Shure's data sheet.
73,
... Joe, W4TV
On 2018-10-10 11:29 AM, Don Wilhelm wrote:
As Bob K4TAX has pointed out and K9YC has long advocated, set the
lower 2 bands of TX EQ to the lowest levels and set the 3rd band down
a bit as well - that will increase your "talk power" while not
wasting power trying to transmit those low frequencies which are not
needed for intelligibility. If you are into ESSB, you may differ,
but ham radio is not HI-FI in my opinion, it is about communications
effectiveness.
The typical
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