K3 RX audio on voice modes <oh no here we go again>

[pd0psb]

Hi fellow Elecrafters,


The K3 is the best & pleasant radio I ever had, but it also is one of the
most ear fatiguing I've ever listened to on voice.

I'm very surprised about this because Wayne's brilliant design should be
able to sound like the very finest sound equipment. The DACs and audio
stages are all top-notch.


I did a couple of tests in my audio studio and came up with the following
(ridiculous?) idea:

-The white atmospheric bandnoise (we all love her) should somewhere down the
line be converted to (near) pink audio noise before it hits our ears. In the
K3 and maybe many other receivers this doesn't happen, white RF noise is
linearly translated to white audio noise, sounding "high emphasized" to the
human ear.

I have a feeling in older receivers this was "mildened" by the electronics
that somehow gave a natural roll-off up the spectrum.


Too simple,right?  I thought so too.


So I built an accurate 3db/octave downsloping filter (in software) and fed
it with the K3's RX audio.

A -3dB/octave downslope converts white noise (equal energy per Hz) to pink
noise (equal energy per octaveband)

For our ears pink noise sounds "flat" since we listen to frequencies in a
logarithmic manner.


How did it sound with or without ?To me, like night and day.

-K3 in "pink mode" sounds round,smooth and balanced out. RX EQ now works
correctly and is able to really shape the sound to many different
"flavours".

-K3 in "white mode" to me sounds mean,agressive and sharp.RX EQ can hardly
correct this.


Could anyone else give this a try? There are quite a lot of software EQ's
able to make a -3dB/octave slope. Or milder slopes if you wish as long as
it's quite precise in dB/oct.

I wouldn't like a new discussion about different tastes of
audio/speakers/headphones/etc but I would be very interested in other people
able to copy this experiment and comment on it.


I have a feeling the K3 can do way(ne) better then it does in the audio
department.


Please excuse my english

73'

Paul

PD0PSB
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[wayne burdick]

paul bijpost wrote:

> The white atmospheric band noise (we all love her) should somewhere
> down the
> line be converted to (near) pink audio noise before it hits our ears.

Band noise is filtered three times before it gets to the AF amp: at the
crystal filter, the DSP I.F. filter, and the DSP A.F. filter. It is
most definitely "pink" by the time you hear it.

However, it seems that we have some customers with such good hearing
that they could benefit from additional rolloff at the output of the
DAC driving the AF amp. Lyle and I are exploring ways to do this. We've
added you to the short list to test anything we might come up with.

73,
Wayne
N6KR

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[pd0psb]

Wayne, I'm sorry to disagree.
White noise will remain white within a restricted bandwidth.
The better/steeper the filters (and the K3 has those) the more the noise character will remain "white" within the chosen bandwidth.
73'
Paul
PD0PSB

Band noise is filtered three times before it gets to the AF amp: at the
crystal filter, the DSP I.F. filter, and the DSP A.F. filter. It is
most definitely "pink" by the time you hear it.
73,
Wayne
N6KR

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[Doug Turnbull]

Where would anyone get such service and attention to detail?   The K3 is a
product whose design is ever being improved!   I truly hope the good people
at Elecrafter prosper for all their good works.   My fear is that as worthy
as government work is that if this gem of a company ever gets out of the
consumer sector then we will have lost one amazing experience.  Owning a K3
and following its development is an exciting trip.   We have serious
technical correspondence between great engineers and intelligent users. The
engineer is happy and able to make changes.  My K3, this forum and
Elecrafter bring additional happiness!
           Thank you Doug EI2CN


paul bijpost wrote:

> The white atmospheric band noise (we all love her) should somewhere
> down the
> line be converted to (near) pink audio noise before it hits our ears.

Band noise is filtered three times before it gets to the AF amp: at the
crystal filter, the DSP I.F. filter, and the DSP A.F. filter. It is
most definitely "pink" by the time you hear it.

However, it seems that we have some customers with such good hearing
that they could benefit from additional rolloff at the output of the
DAC driving the AF amp. Lyle and I are exploring ways to do this. We've
added you to the short list to test anything we might come up with.

73,
Wayne
N6KR


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[pd0psb]

<quote author="Doug Turnbull">
Where would anyone get such service and attention to detail?   The K3 is a
product whose design is ever being improved!   I truly hope the good people
at Elecrafter prosper for all their good works

Fully agree!

The guys (and ladies!) at Elecraft show the greatest courage being such an open company.
We should always consider our input to be constructive to the K line products and community,
so the makers will be having as much fun as us (very lucky!) users.

73'
Paul
PD0PSB

[Barry N1EU]

pd0psb wrote

-K3 in "pink mode" sounds round,smooth and balanced out. RX EQ now works
correctly and is able to really shape the sound to many different
"flavours".

I've been playing with the K3 RX EQ and watching the audio passband response on a spectrum analyzer.  It's not very difficult to configure RX EQ settings to provide 3dB/octave rolloff if that's what you want.  Using a 3.2Khz ssb bandwidth and 1.45Khz center freq, the following RX EQ settings did a good job of approximating the 3dB/octave rolloff on my K3 in USB, although results will vary somewhat depending on your roofing filters:

RX EQ settings for rolloff above 200hz:
0  +8  +2  -3  -5  -10  -16  -16

RX EQ settings for rolloff above 500hz:
0  +8  +2   0  -3   -4   -7   -10

N2BC's K3_EZ software makes it easy to manipulate and save RX EQ settings: http://home.roadrunner.com/~n2bc/SW.htm

73,
Barry N1EU

[Barry N1EU]

pd0psb wrote

-K3 in "pink mode" sounds round,smooth and balanced out. RX EQ now works
correctly and is able to really shape the sound to many different
"flavours".

I've been playing and listening some more.  I have to admit to at first being somewhat dismissive of Paul's suggestions, but not any longer.  I think many listeners will prefer a downward sloping passband response.  I've posted some results and preferences at http://n1eu.com/K3/K3_notes.htm  (scroll down to RX EQ Settings - Pink Noise Rolloff).  

73,
Barry N1EU

[pd0psb]

Thanks Barry!

It's indeed possible to approach the -3db/oct roll of with the RX EQ, but it's not very accurate.(I tried this as well) In the audioworld it is very uncommon the make such drastic correction with EQ to make a source sound "flat"

To have an accurate straight slope of -3db/oct (or a bit less) before the RX EQ and than make (small) EQ corrections to personal taste I'm sure will sound VERY good to everybody and make the K3's audio really shapable for the ear.

73'
Paul
PD0PSB




I've been playing and listening some more.  I have to admit to at first being somewhat dismissive of Paul's suggestions, but not any longer.  I think many listeners will prefer a downward sloping passband response.  I've posted some results and preferences at http://n1eu.com/K3/K3_notes.htm  (scroll down to RX EQ Settings - Pink Noise Rolloff).  

73,
Barry N1EU

[pd0psb]

What about:
TECH MD >> NSE CHR (rx noise character) >> WHT (white) // PNK (pink) ?  ;-)

73'
Paul
PD0PSB

[wayne burdick]

You're right, Paul -- I skimmed right past the "pink" idea (oops) and  
interpreted the poster's concern as a more common one that customers  
have brought up, namely that they can hear higher-order products (above  
the nominal communications passband).

Sloping the response is a very simple thing to do, and we've added that  
to the list. But we're also pursuing the high-order product issue.

Interesting discussion!

73,
Wayne
N6KR

On Apr 25, 2009, at 12:47 AM, pd0psb wrote:

>
> Wayne, I'm sorry to disagree.
> White noise will remain white within a restricted bandwidth.
> The better/steeper the filters (and the K3 has those) the more the  
> noise
> character will remain "white" within the chosen bandwidth.
> 73'
> Paul
> PD0PSB
>
> Band noise is filtered three times before it gets to the AF amp: at the
> crystal filter, the DSP I.F. filter, and the DSP A.F. filter. It is
> most definitely "pink" by the time you hear it.
> 73,
> Wayne
> N6KR
>
> ---
>
> http://www.elecraft.com
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> --  
> View this message in context:  
> http://n2.nabble.com/K3-RX-audio-on-voice-modes-%3Coh-no-here-we-go- 
> again%3E-tp2699273p2702000.html
> Sent from the [K3] mailing list archive at Nabble.com.
>
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[pd0psb]

IMD LPF and "countersloping" combined will make K3 the best sounding radio up to now, trust me.
Let's make music ;-)

73'
Paul
PD0PSB


<quote author="wayne burdick">
You're right, Paul -- I skimmed right past the "pink" idea (oops) and  
interpreted the poster's concern as a more common one that customers  
have brought up, namely that they can hear higher-order products (above  
the nominal communications passband).

Sloping the response is a very simple thing to do, and we've added that  
to the list. But we're also pursuing the high-order product issue.

Interesting discussion!

73,
Wayne
N6KR

[pd0psb]

For whose's interested:
http://en.wikipedia.org/wiki/Colors_of_noise

<quote author="pd0psb">
What about:
TECH MD >> NSE CHR (rx noise character) >> WHT (white) // PNK (pink) ?  ;-)

73'
Paul
PD0PSB

[Geoffrey Downs-2]

Thank you Paul - the Wiki entry was new to me and very interesting. It
demonstrated well to a non-expert such as myself the less aggressive nature
of pink noise compared with white. The red/brown noise sounded even better
to my ears but maybe its spectrum is not as suitable for voice
communication. Anyone care to comment?

73 to all

Geoff
G3UCK

----- Original Message -----
From: "pd0psb" <[hidden email]>

>
> For whose's interested:
> http://en.wikipedia.org/wiki/Colors_of_noise
>
>
> What about:
> TECH MD >> NSE CHR (rx noise character) >> WHT (white) // PNK (pink) ?
> ;-)
>
> 73'
> Paul
> PD0PSB

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[pd0psb]

Geoff,

Pink tends to sound most flat to our ears.
That's why it's widely used to calibrate audio equipment.

Red/brown may sound nice as well, but are relatively "dark"

Funny thing about "white" is that it keeps that agressive nature in a restricted bandwidth, because the high flank will grab the most attention of our ears. I think that may be a reason to cause ear fatigue in the long run.

In analog DIY radio's I've allways tried to maintain a "pinkish" character with a gentle low slope and a steep high.

73'
Paul
PD0PSB

Geoffrey Downs-2 wrote

Thank you Paul - the Wiki entry was new to me and very interesting. It
demonstrated well to a non-expert such as myself the less aggressive nature
of pink noise compared with white. The red/brown noise sounded even better
to my ears but maybe its spectrum is not as suitable for voice
communication. Anyone care to comment?

73 to all

Geoff
G3UCK

----- Original Message -----
From: "pd0psb" <[e-mail]>


>
> For whose's interested:
> http://en.wikipedia.org/wiki/Colors_of_noise
>
>
> What about:
> TECH MD >> NSE CHR (rx noise character) >> WHT (white) // PNK (pink) ?
> ;-)
>
> 73'
> Paul
> PD0PSB

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[Dave Hachadorian]

I have a friend who is considering buying a K3, and last
Saturday I brought one of my K3's over to his house to
compare with his FT-1000 Mk V. We were able to switch an
antenna back and forth between the two rigs and just listen
to snr on weak signals, while playing with NB, NR and
shift/width. We were listening on the rigs' built-in
speakers. Neither rig had a decided advantage in our little
test. He also has heavy line noise from a nearby HV line,
and neither rig was able to help much with that problem.

However, I was astounded at the difference in audio
characteristics between the two radios. The K3 had much more
accentuation of high frequencies. One person might call that
"crisp," while another might call it "harsh." In contrast
the Mk V might be labelled by one person as "mellow," or by
another as "muffled." I tried to get the two radios to sound
the same by playing with their shift/width, but was not
really successful.

I'm not sure which sounds better, especially for long-term
listening, but they sure do sound different.

Dave Hachadorian, K6LL
Yuma, AZ

















.

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[AC7AC]

CONTENTS DELETED

The author has deleted this message.

[pd0psb]

All true Ron!

Fact remains that by law of physics / psycho-acoustics "pink" is perceived by average human ears as flat.
Therfore (I think) it would be nice to start off with a flat noise character, and adjust that per individual by the RX EQ.

You will also notice that the range of the EQ by ear will become larger if it's fed with pink.
So it will still be possible to counter-adjust your personal curve.

73'
Paul
PD0PSB


<quote author="Ron D'Eau Claire">
It's important to note that the spectrum of the noise each of us hears is
*not* the spectrum presented by the source.

Everything we hear is filtered by our ears. In the past youngster's ears
were considered rather 'flat' from perhaps 20 Hz up to above 16 kHz.

It's no wonder there are as many opinions about the "sound" of a rig as
there are people listening...

Ron AC7AC

[Steve Ellington]

One thing I look for is audio stage hiss. Disconnect the antenna, turn down
the AF gain to minimum and listen using hi-fi headphones. You should not
hear anything. The K3 is dead silent. The FT-7000 has some hiss. I use a
headphone attenuator on the FT-7000 to drop the hiss out of my hearing
range.
Next, with the antenna still disconnected, turn down the RF/IF gain to
minimum and increase the AF gain. The K3 is silent. Most Yaesu's, FT-1K
series, tend to have a "milky" hiss coming from the last IF stage. Changing
the RF gain has no effect. I had an FT-1Kmp and that IF stage hiss drove me
to sell it quickly. There is a mod that reduces the gain of that IF stage
but that seems like a poor solution.
With the ant. still disconnected,  turn up the RF gain. Most receivers will
present some noise. This is generated by the RF amplifier. The K3 will
provide plenty of this. Turn on the pre-amp. Now you'll really hear some
noise. I believe the quietest overall I've seen for this test is the
IC-7800. That thing is really quiet.
In the end, being able to hear weak signals is what matters but hearing them
with no noise generated by the radio makes it even better.
Steve Ellington
[hidden email]
----- Original Message -----
From: "Dave Hachadorian" <[hidden email]>
To: "Elecraft reflector" <[hidden email]>
Sent: Tuesday, April 28, 2009 10:08 AM
Subject: Re: [Elecraft] [K3] K3 RX audio on voice modes <oh no here we
goagain>

>I have a friend who is considering buying a K3, and last
> Saturday I brought one of my K3's over to his house to
> compare with his FT-1000 Mk V. We were able to switch an
> antenna back and forth between the two rigs and just listen
> to snr on weak signals, while playing with NB, NR and
> shift/width. We were listening on the rigs' built-in
> speakers. Neither rig had a decided advantage in our little
> test. He also has heavy line noise from a nearby HV line,
> and neither rig was able to help much with that problem.
>
> However, I was astounded at the difference in audio
> characteristics between the two radios. The K3 had much more
> accentuation of high frequencies. One person might call that
> "crisp," while another might call it "harsh." In contrast
> the Mk V might be labelled by one person as "mellow," or by
> another as "muffled." I tried to get the two radios to sound
> the same by playing with their shift/width, but was not
> really successful.
>
> I'm not sure which sounds better, especially for long-term
> listening, but they sure do sound different.
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> .
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
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[pd0psb]

Also true Steve!

The K3 is the most silent I've ever experienced.
Pull the antenna out and you're virtually left with nothing.
That's why I think the "hiss" complaints are caused by its noise character...

73'
Paul
PD0PSB





<quote author="Steve Ellington">
One thing I look for is audio stage hiss. Disconnect the antenna, turn down
the AF gain to minimum and listen using hi-fi headphones. You should not
hear anything. The K3 is dead silent.

[pd0psb]

BTW gentlemen, shall we put the lid on?
We've been occupying quite some (pink) bandwidth!

Thanks for the discussion!
Paul
PD0PSB




<quote author="pd0psb">
Also true Steve!

The K3 is the most silent I've ever experienced.
Pull the antenna out and you're virtually left with nothing.
That's why I think the "hiss" complaints are caused by its noise character...

73'
Paul
PD0PSB

Steve Ellington wrote

One thing I look for is audio stage hiss. Disconnect the antenna, turn down
the AF gain to minimum and listen using hi-fi headphones. You should not
hear anything. The K3 is dead silent.