[Freeswitch-users] Gsmopen weird sound incoming

[Peter Hartmann]

Hey Giovanni,
Thanks for your help.

> You would be better served by an install that is exactly as in the wiki
> page.

OK, understood.


> I've listened to the recordings, but I cannot hear bad sounds, just some
> noise at beginning of recording.
>

Yes, that's the strange sound I'm referring to.  When I'm saying "a
strange sound"  I mean this noise at the beginning, not general sound
quality using Gsmopen.  In spite of having bad signal quality I find
the overall sound quality of Gsmopen quite good!  As I was saying,
sometimes it's 1. not there ,2. only a hiss, 3. sometimes a loud
screech.


> How do you obtain those recordings? Eg: the exact procedure you use to
> produce those files?
>

These particular recordings were done with FS itself just to save me
the trouble of hooking up a telephone recording device.  Unfortunately
my Android phone does not support call recording.   The exact
procedure was calling out through a Google Voice extension into the
Gsmopen endpoint number.     This was only done for the convince of
recording.   The sound happens regardless of how you call in.

For instance, here is a recording I made through a POTS line using
this device:

http://www.radioshack.com/product/index.jsp?productId=2104040

http://hartmanncomputer.com/via-POTS.wav



Thanks again!



Peter Hartmann
Hartmann Computer Consulting


On Mon, Mar 4, 2013 at 5:03 AM, Giovanni Maruzzelli <gmaruzz at gmail.com> wrote:
> On Mon, Mar 4, 2013 at 3:16 AM, Peter Hartmann <peter at hartmanncomputer.com>
> wrote:
>>
>>
>> I'm using Ubuntu 12.04-amd64.  I have done some optimizations for
>> Linux Audio and USB audio. These do seem to have improved the sound
>> quality through the dongle but they haven't solved this weird sound
>> problem on incoming calls.  If anyone's interested, my tweaks were;
>> using the lowlatency kernel and adding 'snd-usb-audio nrpacks=1' to my
>> /etc/modules.
>>
>
> Hello,
>
> you would better unload any *any* snd* module from kernel. mod_gsmopen do
> not use the audio subsystem at all, and those module can't have a positive
> effect, quite possibly negative. mod_gsmopen has nothing to do with ALSA or
> OSS, and do not use sound at all.
>
> You would be better served by an install that is exactly as in the wiki
> page.
>
> mod_gsmopen exchange digital audio directly at sample level with the dongle,
> through the serial interface. That dongle is not seen as an audio card from
> the kernel, but as a modem (exactly as 4 modems).
>
> Also, lowlatency kernel is not required or supported.
>
> I've listened to the recordings, but I cannot hear bad sounds, just some
> noise at beginning of recording.
>
> How do you obtain those recordings? Eg: the exact procedure you use to
> produce those files?
>
> -giovanni
>
>
>
>
>>
>> Has anyone experienced this sound?
>>
>> Thanks much!
>>
>>
>> Peter Hartmann
>> Hartmann Computer Consulting
>>
>> _________________________________________________________________________
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>>
>> 
>> 
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>
>
>
>
> --
> Sincerely,
>
> Giovanni Maruzzelli
> Cell : +39-347-2665618
>
> _________________________________________________________________________
> Professional FreeSWITCH Consulting Services:
> consulting at freeswitch.org
> http://www.freeswitchsolutions.com
>
> 
> 
>
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>
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