[arm-allstar] Distorted audio (sampling?)

[David McGough]

Alessio,

Interesting that rebooting the RPi3B fixes the issue. Does stopping and 
starting Asterisk also fix the issue?

To convert uLAW (pcm) files to wav files, one way is with the sox 
software, like:

sox -t ul -c 1 -r 8000 allstar_audio_file.pcm  output_file.wav


73, David KB4FXC


On Fri, 13 Sep 2019, "Alessio Sacchi via ARM-allstar" wrote:

> Danny, David
> 
> I could certainly take a generator up to the site on my next trip. Speaking
> of adding a tone, I remember I used a "generate continuous tone" in ASL
> usb-tune tool. That helped me at quantifying the distortion back in my ASL
> testing days.YOu kept it running for seconds and the tone broke up
> intermittently eventually.
> 
> There's a quite important update on the degraded audio issue. I continued
> my controlled manner testing by disabling things one by one. Specifically I
> had a script checking gpio to sense loss of mains power - killing it
> doesn't change anything. I eventually tried a reboot which fixed the
> problem immediately. But the issue come back in the same form less than 24
> hours later. Users reported this thing gets worse over time. Another reboot
> fixed it again. I am back doubtful of my power supply, unless you have
> other ideas. Am I wrong thinking 3 ports could be too many for a single PI
> 3B?
> 
> I'll procure some uLAW recordings as soon as I can listen to them. What do
> you reckon to play the uLAW files with? I tried  importing them as raw
> files with audacity with no luck.Maybe I am configuring it wrongly during
> the import.
> 
> Thanks,
> Alessio
> 
> On Thu, Sep 12, 2019 at 5:46 PM "Danny K5CG via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
> 
> > Alessio,
> >
> > It sounds like you need to do some testing in a controlled manner to
> > eliminate as many unknowns as possible.
> >
> > Do you have a service monitor? Generate input RF, add a tone, record it.
> > Is the distortion still there?
> >
> > Danny
> > K5CG
> >
> > ----- Original Message -----
> > From: "ARM Allstar" <arm-allstar at hamvoip.org>
> > To: "ARM Allstar" <arm-allstar at hamvoip.org>
> > Cc: "Alessio Sacchi" <iz4efn at gmail.com>
> > Sent: Thursday, September 12, 2019 9:55:51 AM
> > Subject: Re: [arm-allstar] Distorted audio (sampling?)
> >
> > Hi David, thanks. I will immediately begin recording with uLAW and find a
> > few samples to share.
> >
> > >>is the same noise heard on all your AllStar connected receivers or just
> > one?
> > All connected receivers. To clarify:
> > - A distorsion over a signal coming from the 50MHz port is heard on
> > echolink, on 70cm and on 23cm
> > - Distorsion can happen regardless of the input ports - except for audio
> > coming from echolink. Meaning that signals coming from each of the radio
> > ports can be affected by distorsion. Audio from echolink seems to be pushed
> > out clean at all times.
> >
> > Alessio
> >
> > On Thu, Sep 12, 2019 at 4:01 PM "David McGough via ARM-allstar" <
> > arm-allstar at hamvoip.org> wrote:
> >
> > >
> > > BTW, I noticed that the dropbox .wav files are in the GSM CODEC format.
> > > For diagnosing audio issues, I recommed saving the files using the much
> > > higher audio quality uLAW CODEC, rather than GSM. The negative drawback
> > is
> > > that the files will be bigger, of course.
> > >
> > > To enable saving uLAW formatted files, in your /etc/asterisk/rpt.conf
> > file
> > > node stanzas, add:
> > >
> > > archivetype=pcm
> > >
> > >
> > > 73, David KB4FXC
> > >
> > >
> > > On Thu, 12 Sep 2019, "David McGough via ARM-allstar" wrote:
> > >
> > > >
> > > > Hi Alessio,
> > > >
> > > > To me, the distortion heard in your recordings doesn't sound it's
> > coming
> > > > from the HamVoIP/AllStar software. My first suspicion is noise on the
> > > > receiver audio, which leads me to a question: is the same noise heard
> > > > on all your AllStar connected receivers or just one?
> > > >
> > > >
> > > > 73, David KB4FXC
> > > >
> > > >
> > > >
> > >
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> > >
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> > >
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> >
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> >
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> >
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> >
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> >
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