> The audio LPF that was added to the DSP board has a cutoff frequency
> somewhere near 3.4 kHz if I recall.
The cutoff is 4.2 KHz - the same as the high limit of the DSP.
The K3 does have a very flat passband with steep skirts out to the
hi-cut value. I am guessing that the flat passband is what is
bothering you.
I'm convinced of that ... the vast majority of rigs I've tested over
the years have a low-pass roll off characteristic to their audio -
generally in the 3 to 6dB per octave range from about 5OO Hz up.
This can be simulated in the K3 by setting 400 Hz at 0, 800 at -3,
1600 at -6, 2400 at -8 and 3200 at -9 (3 dB per octave - double
for -6 dB per octave). If one couples the 6 dB/octave roll off
with a bandwidth of 2.6 KHz (200 - 2800 Hz) there is very little
difference in the audio "sound" between the K3 and other mainline
rigs.
I prefer to keep my RX EQ flat from 400-2400 Hz, set 3200 at -16
and bring the bandwidth in to 2.4-2.6 KHz. The "flat" setting at
2400 effectively provides a little intelligibility boost compared
to the other rigs for those times I have to use SSB.
73,
... Joe, W4TV
On 7/21/2013 7:43 PM, Don Wilhelm wrote:
Mike,
If that 'hiss' is reduced when the bandwidth is reduced, then it is
atmospheric noise that you are hearing, not any internally generated noise.
The audio LPF that was added to the DSP board has a cutoff frequency
somewhere near 3.4 kHz if I recall. There is little falloff at
frequencies lower than that.
The K3 does have a very flat passband with steep skirts out to the
hi-cut value. I am guessing that the flat passband is what is bothering
you.
73,
Don W3FPR
On 7/21/2013 7:18 PM, mikerodgerske5...@yahoo.com wrote:
I think the audio voice quality has been remedied long ago.
What lingers is the high end hiss that I and a few others hear.
Apparently this only bothers a minority.
On my 5047 it occurs with hi cut of about 2500 and gets worse to 3000.
If you run bandwidth 2.1 or below you will never hear it. 2.4 probably
hear it some.
It's most prevalent scanning a vacant band 6-20. Not as noticeable
when people are talking.
On the noisier bands I'm not sure you hear it at all. I was on 40 the
other night using NR and didn't hear it.
This issue in general comes up frequently on other groups and is
negative press. It's usually called something like fatigue factor like
during a contest. I think some of this is holdover and bad press
before the dsp upgrade several years ago. I don't see anything wrong
with the audio itself, just the high end hiss. My top 3 eq bands at
-16 by the way.
Something that comes up also is how well the k handles lightning noise
spikes in agc and why can't others do it? That's positive press.
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