Yamaha CM500 Headset

Yamaha CM 500 headset setup for K3

You set up the microphone to match your K3. The settings will depend on how you talk into the mic, so this is an individual setting.
First turn the compression to zero, then increase the mic gain until you
see 6 to 7 bars on the ALC meter.
Then add compression as you like.

You can do all that in TEST mode.  When adding compression, you can
listen to yourself on the monitor.

“I have my CM-500 that arrived yesterday directly to the radio rear mic input and the BIAS enabled at “rP.L bIAS” and it works great.”

“I just received my CM-500s and am using the rear mic jack. Works fine that
way with lo gain, bias on…. the mic has a lot of gain. It’s quite bassy compared to the
Heil but the EQ takes care of that.”

“I cut the lows with the EQ and my audio goes now from 150 to 3100hz,its easy to EQ any mic wiith the K3.”

- Set the mic gain to the high range.  That’s in the MAIN:MIC SEL
menu.

- Make sure the bias is turned on; it probably is or you wouldn’t hear
anything.

- Start with MIC gain set to about 20 and see how that works.  Adjust
CMP and MIC according to the instructions in the manual, watching ALC
- etc.  FWIW, I found the MIC gain set to about 30 is right for my
voice here.  YMMV.

- If you need to adjust the MIC gain up, be sure and listen to
yourself using a MON setting that allows you to hear your TX audio. TX
TEST mode works well for this; there’s no need to do on-air tests at
first.  Plus, if it sounds good to you it will probably sound good for
everyone else.

I just got CM500′s working here this afternoon.  The little electret
power box is handy in my case, because I use the rear panel MIC/SPKR
for room audio and the front panel MIC/PHONES sockets for the CM500. I
just replaced the 3.5mm cable/plug with a shielded cable with
MIC+/BIAS/GND signals and it all works fine.

TXEQ settings

BEFORE setting front panel mic gain, go to TXEQ and turn down the two lowest octaves as far as they go (-16dB). Leave all the other octave bands set flat (OdB), or set them to 0dB if you have changed them for some other mic. Set the Mic Gain in the menu to Low. NOW, follow the instructions in the K3 manual for setting mic gain (the proper ALC reading when you talk with Compression turned off), then turn up Compression to get the desired amount as indicated on the front panel meter (but don’t go more than 10dB of compression on peaks). THEN, get some on the air reports from a “good listener” who has his/her radio set for wide SSB RX bandwidth (a wide IF setting), and tweak the TXEQ settings if needed for YOUR voice. If you have a deep or muddy voice, you might want to roll off a bit of the third lowest octave and/or increase the two highest octaves by a few dB.

BTW — the only difference between setting up this mic and any other
mic is the TXEQ settings that correspond to the response of THAT mic
and YOUR voice, and the Mic Gain setting for that mic.

The K3 transmit equalizer has eight bands. Per the K3 manual, “The center frequencies of the 8 audio EQ bands are 50, 100, 200, 400, 800, 1600, 2400, and 3200 Hz.”  Clearly, the lowest band is irrelevant for human speech and can be knocked down to -16 dB without losing any speech.  The second band, centered at 100 Hz, will partially cover the low end of the human male voice range, especially for males, but as stated above, you can knock out the primary frequency and still transmit intelligible speech because of the harmonics of the primary frequency. It might sound a little “tinny”, but it will be fully intelligible. A female user of the K3 might want to knock the third equalizer band all the way down to -16 dB as well as the first two. These would be typical settings for SSB contesting where you want to maximize the modulated signal in the frequency band where it will have the most effect.

If you’re a fan of “broadcast quality” AM rag-chewing, you’d definitely want to use different settings, probably “flat” except for the lowest band for males and the lowest two bands for females.

I just re-checked my K3, and I am set to “MENU/MIC SEL=rP.l biAS”, MIC Gain knob is 17, CMP is 22.  I have the first 3 sliders in the TX EQUAL most of the way down (-12 to -16) and the top 2 up maybe +3.

I get 7-8 bars of Audio/ALC and 10+ on the Compressions scale.  I’m getting good audio reports from contacts.