K3 RX Audio
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Good quality transmit audio, be it from outboard processing gear or other
needn't consume excessive bandwidth, though some does. Nor does it need to be excessive in any of its characteristics. I appreciate quality receive audio beyond that of simply 'communications quality.' I routinely run my K3 filters on receive at 2.4 and 2.4 kHz and roll off the high end to avoid sound that I don't care to hear. There are occasions where I open it up to 2.8 or 3.0 kHz when signal to noise ratios are high and the audio I am listening to justifies it. Usually those cases are few. I don't pretend to know all the issues in the receive chain of audio, but I do think improved audio can be found for not a lot of cost in terms of design and components. It seems the dressed down style of Silicon Valley is now near ubiquitous. Dick - KA5KKT - Truth is not a popularity contest ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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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. 73 Mike R ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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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, [hidden email] 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. > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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> 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, [hidden email] 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. >> >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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That could be what it is. The "hissy" sound that some folks are hearing is probably simply a passband that's unusually flat. Those interested should familiarize themselves with the plots on Barry N1EU's page: http://n1eu.com/K3/K3_notes.htm .
So, I am not sure why, if at say, 2.8 kHz you find the "hiss" objectionable, you wouldn't simply limit the upper cutoff frequency to 2.75 kHz??? I find 3.4 kHz too noisy; I leave my HI CUT frequency far below that point, always. That's why that control is variable. There might be another factor involved. I don't recall if I made this point before-- and I apologize if I am repeating myself-- but I find that hams who grew up copying signals buried in QRM on less-than-perfect receivers tend to do much better later in life dealing with the psychoacoustical effects this thread has morphed into discussing. But this is only an anecdotal observation and I think some psychology student somewhere should do their dissertation on this! > 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. For a similar reason, we have hams who dislike copying stations who are less than S9. The 'ear-brain filter' that you hear about is an amazing thing, but especially if the skill to use it has been cultivated from a young age. Al W6LX ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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