You can try using a softphone from another computer, or an Android/IOS client and see if the distortion is still present. There's a number of possibilities- incorrect mic levels, timing issues, no jitter buffer on FSClient, so external testing will help narrow it down.
Zoiper communicator is good for this, as is Xlite and a few others. 3CX _might_ still work, if they haven't dumped the free SIP version yet? Better still, if you have a hardphone with current firmware, that's a better point of reference again.

On 14/01/2014 10:34 PM, Fredrik Åhlén wrote:
Hi everyone,
this is my first exeperience with FreeSwitch. I just downloaded FreeSwitch and installed it on Windows 7 using the MSI-installer. I think it’s verision 1.5.7b, at least according to the output from fs_cli.exe. The installation is pure local on my own home LAN (100 mbit), i.e no VOIP gateways etc.
 
I am playing around with the installation and the FSClient 1.2.3.5 as softphone calling the echo test, calling between extension 1000 – 1001, voice mail 4000 etc. Everything seems fine but the sound is somewhat distorted. The sound is a little/somewhat scratchy. I’ve tried to change codec in FreeSwitch and/or the FSClient but without luck. Since I am completely new to FreeSwitch I thought that I would ask the community about it.
 
What might cause this sound distorsion? I have recorded the sound but I was not sure it I should attatch it or not. Any help is appreciated.
 
Output from fs_cli.exe:
“
freeswitch@internal> version
FreeSWITCH Version 1.5.7b+git~20131111T224713Z~5456daa010~32bit (git 5456daa 201
3-11-11 22:47:13Z 32bit)
“
 
From vars.xml:
“
<X-PRE-PROCESS cmd="set" data="global_codec_prefs=G722,PCMU,PCMA,GSM"/>
<X-PRE-PROCESS cmd="set" data="outbound_codec_prefs=PCMU,PCMA,GSM"/>
“
 
With Best Regards,
Fred
 


_________________________________________________________________________
Professional FreeSWITCH Consulting Services:
consulting@freeswitch.org
http://www.freeswitchsolutions.com

FreeSWITCH-powered IP PBX: The CudaTel Communication Server
http://www.cudatel.com

Official FreeSWITCH Sites
http://www.freeswitch.org
http://wiki.freeswitch.org
http://www.cluecon.com

FreeSWITCH-users mailing list
FreeSWITCH-users@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-users
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
http://www.freeswitch.org