[CQ-Contest] Boom for Bose Headset

Jim Brown k9yc at audiosystemsgroup.com
Tue Mar 3 19:44:03 EST 2015

On Tue,3/3/2015 12:12 PM, donovanf at starpower.net wrote:
> This is a relatively inexpensive microphone that can be easily
> attached to most headphones
> http://www.modmic.com/collections/frontpage  

Looks nice, guys. One caution when you get around to using it. The data 
sheet says it's unidirectional, meaning that it's a cardioid, and it 
seems to be an electret condenser mic. Cardioids have proximity effect 
-- bass boost that increases as it gets closer to the sound source. This 
emphasizes the low end of the voice, AND it emphasizes breath pops and 
handling noise. Also, condenser mics are sensitive to breath pops.

For these reasons, it's important to do two things.

1) Don't use it too close to your mouth, and don't talk straight into 
it. I adjust my Yamaha CM500 so that it's a few inches above and to the 
side of my mouth. (This yields the added advantage of allowing us to 
drink and munch).

2) Use settings in your rig to get rid of as much low frequency content 
as you can. The lows burn TX power, but make no contribution to speech 
intelligibility. I set up my K3 TXEQ for max cut of the three lowest 
octave bands (50, 100, 200 Hz) and 4-6 dB cut of the 400 Hz band. When I 
ran FT1000MPs, I set the audio bandwidth for 400-2,600 Hz.

IMO, ALL mics and radios should kill those lower three octaves, and what 
is needed for the 400 Hz band and on the high end will depend on the 
voice and the mic. From the earliest days of SSB, the hams at Shure 
designed a mic with an HF peak around 3 kHz to compensate the rolloff of 
the SSB filter, and most ham mics do that to some degree. When I used a 
pro mic with my radios, I had to add that peak with EQ.

73, Jim K9YC

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