Topics

Soft mute disable


Ken Kizer
 

On Sat, 10 Oct 2020 15:22:10 +0200, Rémy Friess via groups.io
<rfriess=rfnet.fr@groups.io> wrote:

OK, now I see what you mean by soft-mute. But mind you, on the PL380 it
can be deactivated relatively simply. Here's how to go about it:

1/ press VF

1 [2]/ tune the receiver to an unused SW frequency.

2 [3]/ press and hold VF

4/ when the receiver starts scanning tune down. The background noise
becomes stronger, which shows that this "soft-mute" is no longer active.

Unfortunately it becomes active again when you switch the set off, and
so you have do it all over again when you switch it on again.

It might work with other Tecsun models, I don't know. Maybe you could
try it with the PL-330. It might also improve the action of the synch
detector.

Regards,

Rémy.
Brilliant. The only thing I've seen that works with the PL-390, the
model I own.


Gord Seifert
 


   I have a PL-310et and I do not notice any change when trying these soft mute disable proceedures. But then, I don't notice any soft mute at all on this radio. Turning it off and on does not reinstate soft mute. Is there a way that soft mute could have been locked off? As it is I have no complaints, it is a very good radio. Just trying to understand.

   Regards,
   Gord S


Paul S. in CT
 

AM-BCB and SW bands are handled differently IIRC. My proceedure was for AM-BCB w/10kHz spacing.
I will check SW usiing AM-BCB proceedure on the PL330.

Paul S. in CT FN31nl


Paul S. in CT
 

Update: the PL-330 does not defeat Soft Mute by tuning +/- 1kHz on the SW bands. Checked 9690 Spanish and it did not work. I know my PL-310 (before the 'et') also did this. One does need a reletively strong SW station. For example 9690 was 42:19 on frequency and when offset.The indication Soft Mute is defeated is the double zero on the right of the strength display. I get xx:00 on AM-BCB, not on SW

Regards
Paul S. in CT FN31nl


gordrstaples
 

When I was referring to defeating soft mute, I meant particularly on the AM band, not the SW band.  If you try to tune a station on say AM 760 and then retune to 759 or 761, this gets rid of the soft mute action and the station audio then does not 'pump' with increasing or decreasing signal strength.  The audio level however does drop a bit when retuning +- 1Khz but can be compensated by increasing the volume level.  This technique works well on the Tecsun PL380 and PL390 radios. Note that the soft mute "feature" is not as aggressive on some Tecsun models as on others and also depends on the manufacture date. I have a PL380 from the year 2010 which soft mute is not nearly as aggressive as another which was manufactured in 2016.  😷


On Sun, Oct 11, 2020 at 3:50 PM Paul S. in CT <dxrx@...> wrote:
Update: the PL-330 does not defeat Soft Mute by tuning +/- 1kHz on the SW bands. Checked 9690 Spanish and it did not work. I know my PL-310 (before the 'et') also did this. One does need a reletively strong SW station. For example 9690 was 42:19 on frequency and when offset.The indication Soft Mute is defeated is the double zero on the right of the strength display. I get xx:00 on AM-BCB, not on SW

Regards
Paul S. in CT FN31nl






mediumwavedx
 

Hi Guys,

Interesting this subject comes up on soft mute. I've been working on a blog post about soft mute and just what it is and its technical parameters.

Here's the data on soft mute:

What is soft mute?
 
Soft-mute is a further lowering of the audio level of the received signal when it drops below a prescribed signal-to-noise ratio. It was implemented in consumer grade DSP radios to provide a more "comfortable listening experience" for the casual listener and not the DXer. The idea is to relieve the listener from all that nasty low level "static" and "interference", or as Silicon Labs states: "....to attenuate the audio outputs and minimize audible noise in compromised signal conditions."
 
Soft mute attenuation is available in the Si473x digitally-tuned series of chips as well as the Si483x analog-tuned series of chips. The soft mute feature is triggered by the SNR (signal-to-noise) metric. The SNR value is directly readable by the chip's software when you tune to a station. The SNR threshold for activating soft mute is programmable, as are soft mute attenuation levels, attack/release rates and attenuation slope.
 
The Tecsun PL-380, PL-310, PL-330, and other radios all may set different soft mute values than the chip's default values shown below. Settings for soft mute are initialized during the power up sequence.
 
The 4 soft mute parameters: Rate, Slope, Max Attenuation, Threshold.
 
Rate (default): 278 dB/second (range 1-255, actual figure 278 = setting * 4.35)
Determines how quickly soft mute is applied/released when soft mute is allowed (enabled). 
 
Slope (default): 2 dB (range 1-5 dB per dB of SNR)
The attenuation slope for soft mute application - in dB of attenuation per dB SNR below the soft mute SNR threshold. Translated: how much audio attenuation to applied as the SNR and signal quality decreases. A setting of 2 will lower the audio by 2 dB for each 1 dB reduction of SNR below the starting threshold at which soft mute kicks in. An example: soft mute starts to kick in when the SNR decreases to 10 dB. At 10 dB, there is 0 dB of soft mute. When the SNR decreases to 9 dB, soft mute reduces the audio level by 2 dB. When the SNR decreases to 8 dB, soft mute reduces the audio level by another 2 dB (4 dB total). By the time the SNR hits 2 dB, the soft mute has reduced the audio level to a max of 16 dB. It will go no lower as the max soft mute has been applied. Note that every 6 dB of audio reduction is a halving of the audio voltage level. 12 dB of reduction is then 1/4 of the original audio voltage level. 16 dB (max soft mute) is a reduction of 84.2% (0.158).
 
Max Attenuation (default): 16 dB (range 0-63 dB, max attenuation of soft mute)
If set to 0, soft mute is disabled entirely.
 
Threshold (default): 10 dB (range 0-63 dB, SNR at which soft mute starts to engage). Silabs states, "for a tuned frequency".
 
Note that the Threshold setting is applicable only "for a tuned frequency". I take this to mean that soft mute is dis-engaged totally when not tuned to an exact 9 or 10 KHz channel, which is apparently why the 1 KHz off-tuning hack works.
 
What you're hearing when a signal's SNR lowers below the threshold and the soft mute kicks in is the Slope factor in action. The Slope factor is lowering the audio volume accordingly.
 
Two other interesting parameters effecting tuning and seeking.
 
AM Seek/Tune SNR Threshold.
SNR Threshold which determines if a valid channel has been found during Seek/Tune.
Specified in units of dB in 1 dB steps (0–63). Default threshold is 5 dB.
 
This tells us that when you do a scan, only stations with >5 dB SNR are elegible to be stored.
 
AM Seek/Tune Received Signal Strength Threshold (RSSI).
RSSI Threshold which determines if a valid channel has been found during
Seek/Tune. Specified in units of dBµV in 1 dBµV steps (0–63). Default threshold is
25 dBµV.
 
This tells us that when you do a scan, only stations with >25 dBµV RSSI are eligible to be stored.

Bill
RADIO-TIMETRAVELLER
https://radio-timetraveller.blogspot.com


Paul Blundell
 

Thank you for that excellent post with such good and interesting information, it explains a lot of what people have been experiencing.

Paul

On Mon, Oct 12, 2020 at 8:20 PM mediumwavedx <desertbilly@...> wrote:
Hi Guys,

Interesting this subject comes up on soft mute. I've been working on a blog post about soft mute and just what it is and its technical parameters.

Here's the data on soft mute:

What is soft mute?
 
Soft-mute is a further lowering of the audio level of the received signal when it drops below a prescribed signal-to-noise ratio. It was implemented in consumer grade DSP radios to provide a more "comfortable listening experience" for the casual listener and not the DXer. The idea is to relieve the listener from all that nasty low level "static" and "interference", or as Silicon Labs states: "....to attenuate the audio outputs and minimize audible noise in compromised signal conditions."
 
Soft mute attenuation is available in the Si473x digitally-tuned series of chips as well as the Si483x analog-tuned series of chips. The soft mute feature is triggered by the SNR (signal-to-noise) metric. The SNR value is directly readable by the chip's software when you tune to a station. The SNR threshold for activating soft mute is programmable, as are soft mute attenuation levels, attack/release rates and attenuation slope.
 
The Tecsun PL-380, PL-310, PL-330, and other radios all may set different soft mute values than the chip's default values shown below. Settings for soft mute are initialized during the power up sequence.
 
The 4 soft mute parameters: Rate, Slope, Max Attenuation, Threshold.
 
Rate (default): 278 dB/second (range 1-255, actual figure 278 = setting * 4.35)
Determines how quickly soft mute is applied/released when soft mute is allowed (enabled). 
 
Slope (default): 2 dB (range 1-5 dB per dB of SNR)
The attenuation slope for soft mute application - in dB of attenuation per dB SNR below the soft mute SNR threshold. Translated: how much audio attenuation to applied as the SNR and signal quality decreases. A setting of 2 will lower the audio by 2 dB for each 1 dB reduction of SNR below the starting threshold at which soft mute kicks in. An example: soft mute starts to kick in when the SNR decreases to 10 dB. At 10 dB, there is 0 dB of soft mute. When the SNR decreases to 9 dB, soft mute reduces the audio level by 2 dB. When the SNR decreases to 8 dB, soft mute reduces the audio level by another 2 dB (4 dB total). By the time the SNR hits 2 dB, the soft mute has reduced the audio level to a max of 16 dB. It will go no lower as the max soft mute has been applied. Note that every 6 dB of audio reduction is a halving of the audio voltage level. 12 dB of reduction is then 1/4 of the original audio voltage level. 16 dB (max soft mute) is a reduction of 84.2% (0.158).
 
Max Attenuation (default): 16 dB (range 0-63 dB, max attenuation of soft mute)
If set to 0, soft mute is disabled entirely.
 
Threshold (default): 10 dB (range 0-63 dB, SNR at which soft mute starts to engage). Silabs states, "for a tuned frequency".
 
Note that the Threshold setting is applicable only "for a tuned frequency". I take this to mean that soft mute is dis-engaged totally when not tuned to an exact 9 or 10 KHz channel, which is apparently why the 1 KHz off-tuning hack works.
 
What you're hearing when a signal's SNR lowers below the threshold and the soft mute kicks in is the Slope factor in action. The Slope factor is lowering the audio volume accordingly.
 
Two other interesting parameters effecting tuning and seeking.
 
AM Seek/Tune SNR Threshold.
SNR Threshold which determines if a valid channel has been found during Seek/Tune.
Specified in units of dB in 1 dB steps (0–63). Default threshold is 5 dB.
 
This tells us that when you do a scan, only stations with >5 dB SNR are elegible to be stored.
 
AM Seek/Tune Received Signal Strength Threshold (RSSI).
RSSI Threshold which determines if a valid channel has been found during
Seek/Tune. Specified in units of dBµV in 1 dBµV steps (0–63). Default threshold is
25 dBµV.
 
This tells us that when you do a scan, only stations with >25 dBµV RSSI are eligible to be stored.

Bill
RADIO-TIMETRAVELLER
https://radio-timetraveller.blogspot.com



--
Paul


Paul S. in CT
 

Regarding Soft-Mute on the SW Frequencies.
It appears that there is a way to defeat the Soft-Mute in my Tecsun PL-330.
A bit tricky, and found it by listening to SW after AM-BCB.

1.) Tune-in to your fave AM-BCB station, and set the Fine Tune to 1kHz,
then tune 1kHz above/below to defeat the Soft-Mute.

2.) Change bands to SW and tune-in to a time-signal station 3331, 5001,
or 10001 kHz... note the deliberate offset of 1kHz. Make sure Fine Tune
is still engaged. On my PL-330 the signal reading looks like 31:00. By
tuning to correct frequency, the signal reading is 31:14. Note the 00
of the original reception. Now alter the tuning 1kHz, and the display
should show 00 again.

I then checked Radio Romania Int'l (RRI) on 7375kHz and the soft-mute was disabled when offset.
I then shut off the radio with this trick enabled, and upon power on the softmute was still disabled.

But then I wonder why the set did not defeat the soft-mute when originally tested last week. It could be that I did not engage the Fine Tune AND offset by 1kHz. Not sure... but this works now.

It may only apply to my model, but worth a couple of minutes to check.

Regards
Paul S. in CT FN31nl