[Elecraft] : K3 receiver noise questionable test results

[Joe Subich, W4TV]

> If that's the case, then the K3's receiver equalizer can be set up 
> to mimic a pink rolloff which is -3 dB per octave.
> 
> 50 Hz : + 9 dB
> 100 : + 6
> 200 : + 3
> 400 : 0
> 800 : - 3
> 1600 : - 6
> 3200 : - 9

If one is going to attempt to mimic the "pink noise" behavior, 
there is no need to bother with the low frequency boost.  It 
simply puts more strain on the audio amplifier, increasing the 
amount of IMD products, with little or no aural benefit.  A 
better RX EQ configuration with essentially the same perceived  
sound: 

  50:  -16 dB (reduce sub-vocal noise and hum) 
 100:    0 dB 
 200:    0 dB 
 400:    0 dB 
 800:    0 dB 
1600:   -3 dB 
2400:   -5 dB 
3200:   -6 dB  

Note: the K3 RX EQ would be more useful (and more intuitive to 
adjust) if the 8 bands had a constant Q response and were based 
on 2/3 octave frequencies - specifically: 

  1   100 Hz 
  2   160 Hz
  3   250 Hz 
  4   400 Hz
  5   630 Hz
  6  1000 Hz
  7  1600 Hz
  8  2500 Hz

Additional controls at 63 and 4000 Hz would be worthwhile if 
a 10 band configuration were possible.  However, since audio 
below 100 Hz and above 3000 Hz is generally not used for 
communications purposes and the K3 DSP response is limited 
to 4200 Hz, making bands 1 and 8 "shelving" instead of peaking 
responses would be a usable alternative to the additional bands.  

73, 

   ... Joe, W4TV 
 




> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Luis V. Romero
> Sent: Saturday, December 19, 2009 12:50 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] : K3 receiver noise questionable test results
> 
> 
> Kudos to Al for supplying these settings that make my K3 
> #3192 sound almost identical to my TS570D (albeit, into 
> different speakers, but lets not open up THAT can of worms)!
> 
> -Lu-W4LT-
> 
> From: "Al Lorona" <alorona at sbcglobal.net>
> Cc: <elecraft at mailman.qth.net>
> Sent: Saturday, December 19, 2009 3:40 AM
> Subject: Re: [Elecraft] K3 receiver noise questionable test results
> 
> 
> > But a few of the K3 owners that have pro-audio  
> instrumentation have 
> >reported that the K3 audio  response is more like 'white 
> noise' (a flat 
> >response), as opposed to other receivers which have a 'pink
> > noise' audio spectrum.
> 
> If that's the case, then the K3's receiver equalizer can be set up 
> to mimic a pink rolloff which is -3 dB per octave.
> 
> 50 Hz : + 9 dB
> 100 : + 6
> 200 : + 3
> 400 : 0
> 800 : - 3
> 1600 : - 6
> 3200 : - 9
>