[TenTec] 2.037J Speech Processor

Thomas Jednacz tjednacz at ieee.org
Mon Sep 11 15:54:46 EDT 2006


> I agree with Ron.  With 2.034, it sounded pretty distorted 
> with SP settings 
> higher than 3.  Now I can go up to 4 or 5 with acceptable results.
> Another problem I had with prior firmware, one that I haven't 
> seen written 
> about here, concerned the DVK.  The output level was much 
> lower than it should 
> be.  That has been fixed in 2.037j.
> 73,
> Ray W2RS

Ray - I don't understand. Did you reduce the mic gain as you increased the
speech processor? I have absolutely no distortion running the speech
processor up to 9. During this past weekend WAE SSB contest I got multiple
reports of outstanding audio and very strong audio. It is unusual to get
reports like this in a contest because it slows down the DX fellows. The
fact that they took the time to comment is impressive. This was running SP
at 6 and Mic Gain at 44 with a Heil headset using the 5 microphone module
and TX EQ at 0 for my voice.

Version 2.037j has dramatically improved the speech processor and the
interaction with VOX. As you increase the SP you have to reduce the Mic
Gain. Reducing the Mic Gain necessary to run SP of 8 places the gain so low
that the VOX does not have enough sensitivity to trip. Example: SP=9, mic
has to be set at "4" and at this level the VOX does not trip even set on
"1". It appears that the speech processor is somewhat linear from 1 to 7 but
increases in processing power non linearly from 7 to 9. Rechecking how it
sounds at SP=9, it now sounds as clean at 9 as it does at 4 - just set an
appropriate Mic Gain.

In detail tests I found that I have to really overdrive the audio to get
distortion with the speech processor. The algorithm used in the speech
processor plus the software filter that follows the compression allow for
some overdrive without splatter or distortion. You have to really push it to
get distortion in my tests.

73, Tom, W7QF

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