OP25 OP25 Volume increase by radio ID

[TheAlmightyZach]

I'm in an odd situation.. our dispatchers all of a sudden got QUIET and they have been for a while now. The agencies haven't said anything to encourage them to raise the volume or anything, but they are hard to hear both on OP25 and my SDS100. Is it possible to increase volume by their radio IDs? Alternatively, is there any way to maybe normalize the volume so that it's all about at the same level?

I think the answer for both questions is no, but worth asking. @boatbod - I do want to mention that I've been using OP25 to host my feed for over a year now and it's been fantastic. Fantastic software!

 

[boatbod]

I'm in an odd situation.. our dispatchers all of a sudden got QUIET and they have been for a while now. The agencies haven't said anything to encourage them to raise the volume or anything, but they are hard to hear both on OP25 and my SDS100. Is it possible to increase volume by their radio IDs? Alternatively, is there any way to maybe normalize the volume so that it's all about at the same level?

I think the answer for both questions is no, but worth asking. @boatbod - I do want to mention that I've been using OP25 to host my feed for over a year now and it's been fantastic. Fantastic software!

Actually there is a way to normalize the volume if you use the liquidsoap method of playback. Suggest making contact with member @wgbecks as he can guide you how to set it up.

 

[TheAlmightyZach]

Actually there is a way to normalize the volume if you use the liquidsoap method of playback. Suggest making contact with member @wgbecks as he can guide you how to set it up.

Thanks! I just ran a quick search to see your information posted here: OP25 - Experiments with op25 and liquidsoap I'll have to play around with it a bit. I appreciate it!

 

[boatbod]

Thanks! I just ran a quick search to see your information posted here: OP25 - Experiments with op25 and liquidsoap I'll have to play around with it a bit. I appreciate it!

Getting liquidsoap to play the audio is just one part of the puzzle. The real meat of normalization is the stream-processing tools that you can add on once you have a working .liq script.

 

[wgbecks]

Zach,

As @boatbod stated, I've have some experience with normalization tools in liquidsoap and would be happy to lend a hand if you haven't already found the information that you're looking for.

 

[wgbecks]

@boatbod has pushed a new op25.liq script to Git Hub that includes audio filtering and normalization that can be enabled by simply uncomment the lines in the script. It will be necessary to cd ~/op25 then git pull. But before you do the git pull you must either delete or rename your existing op25.liq file. Failure to do so with result in an error message when executing git pull.

Try this from your ~/op25/op25/gr-op25_repeater/apps folder. mv op25.liq op25.liq.bak
Now form ~/op25 folder you can now submit git pull and the new op25.liq will be placed in your ~/op25/op25/gr-op25_repeater/apps folder.

Now its just a matter of editing your old file that's now named "op25.liq.bak" and copying your specific configs into the new "op25.liq" and restart liquidsoap.

You could just paste in the audio processing lines into the existing op25.liq script but you'll still have to deal with this the next time you perform a git pull to install a future update.

Here is what the audio processing code looks like in the new script.

# OPTIONAL AUDIO SIGNAL PROCESSING BLOCKS
# Uncomment to enable
#
# High pass filter
input = filter.iir.butterworth.high(frequency = 200.0, order = 4, input)
# Low pass filter
input = filter.iir.butterworth.low(frequency = 3250.0, order = 4, input)
# Normalization
input = normalize(input, gain_max = 3.0, gain_min = -3.0, target = -16.0, threshold = -40.0)

NOTE: For tighter normalization (level control), change the gain_max = 3.0 and the gain_min = -3.0 in the
Normalization block above to: gain_max = 0.0 and gain_min = 0.0

You may need to increase the audio gain from op25 into the processing blocks, depending upon how low audio
levels get on your particular system. This accomplished by changing the "./audio.py -x 2 -s"))
to "./audio.py -x 2.5 -s")) as shown below.

input = mksafe(input.external(buffer=0.25, channels=2, samplerate=8000, restart_on_error=false, "./audio.py -x 2.5 -s"))

Bill

 

[NCAmateurRadioGuy]

@wgbecks,
Is the new normalize function equivalent to the nrj function you explained before or should/can they be used together?

 

[wgbecks]

@wgbecks,
Is the new normalize function equivalent to the nrj function you explained before or should/can they be used together?

Yes it is. However the nrj is not directly supported in the liquidsoap version that runs on Raspbian (Debian-9) Stretch whereby
those signal processing blocks now present in op25.liq will run on Stretch as well as Buster.

 

[NCAmateurRadioGuy]

Yes it is. However the nrj is not directly supported in the liquidsoap version that runs on Raspbian (Debian-9) Stretch whereby
those signal processing blocks now present in op25.liq will run on Stretch as well as Buster.

Good to know, I’ve been trying to keep my OP25 installs up to date to avoid any massive reconfig work in the future.