[TenTec] Audio quality issue in Heil headset with Omni V

[rick denney]

As I have worked through integration issues with my new (to me) Omni
V, I'm finally ready to try and understand an issue I've had all
along.

In my Heil Pro Set headset, the sound from the headphone output of the
Omni is distorted. There is a loud fuzz in the audio.

I have the monitor volume turned up so that my voice in the boom mike
is about the same as the person I'm communicating with when the audio
is where I want it. But at any volume setting of either AF or the
monitor pot, I get the distortion.

I don't get the same problem with these headphones plugged into my
Kenwood TS-430, so it doesn't seem to be fault in the headphones.

The audio does not show clipping on a scope, with the scope lead
connected to the center pin on the headphone receptacle. I mean, I can
MAKE it clip, but that sounds no worse than if I don't, especially
when the processor is enabled. The point is, when I look at a
sine-wave output in the headphones, I don't see the fuzz that I'm
hearing in my ears when I plug the headphones back in. That tells me
that the headphones themselves are part of the problem.

The sound I'm hearing seems like it would be cause the waveform to
glitch with transients, but I don't see that. The waveforms look
smooth.

My ears seem to think it's an impedance mismatch between the
headphones and the audio output. It doesn't seem to be in the
transmitted output, but I haven't had enough signal reports to know
for sure.

Any ideas of things to check?

Rick, KR9D

---
Richard W. Denney, Jr. PE|Iteris, Inc.
Associate Vice President |107 Carpenter Dr. Ste 230 |    703.925.3819
rwd at iteris.com           |Sterling, VA 20164        |Fax 703.471.1757