[arm-allstar] multiple echo link connections and "under water" audio

[W4EDP - Emmett Perdue]

It’s not just you.  I have one that does the exact same thing and have heard many others as well.  Everyone that I have head this issue with is based on either Allstar or HamVOIP.

On mine, I have played with every adjustment I can find, I have moved URI’s away from radios, I have tried chokes on cables, etc.  Using the same radio and a Windows (yuk) based Echolink setup, the problem is 100% removed, so it is something related to Echolink and Asterisk or one of the modules being used.

As a note, I find what you have found to be true everywhere I have heard this issue... Echolink to Echolink is generally good,  Echolink back to net is generally good.  Same on number of users, if it’s only 1 or 2, generally no issue is heard, as soon as there are 3 or more problems starts.  It varies, same person can be “under water” on a transmission, then on their next, sound fine.

I’ve searched and searched, I can find others talking about the issue, but no solutions and people just live with it hoping one day something will change.

73
W4EDP

> On Feb 13, 2020, at 7:49 PM, Patrick Perdue via ARM-allstar <arm-allstar at hamvoip.org> wrote:
> 
> 
> Hi all:
> 
>     I realize that echo link isn't the primary focus of this group, as
> it relates to HamVoIP, but perhaps some of you may have suggestions.
> 
> I'm running a bridge between Allstar, DMR, DSTAR and echo link using
> HamVoIP, DVSwitch and XLXD. I've found that, if only one echo link
> station is connected, audio is as good as it can be, considering the GSM
> codec used by echo link, but subsequent stations hear any audio from
> Allstar as "under water." Echo link to echo link sounds OK, and echo
> link back to Allstar is fine as well.
> I've heard this on a few Allstar to echo link bridges other than mine,
> and it sounds like GSM is being transcoded to GSM a second time. You can
> mostly understand what is being said, but the artifacts are doubled. I
> don't really understand how chan_echolink works, or why additional
> transcoding would be happening at that stage, but that's what it sounds
> like to me.
> 
> The echo link bridge is on it's own private node. Should I force GSM or
> G726 connections only for that node, or will that just make things worse?
> 
> I don't know for sure if it's multiple connections causing this
> behavior, or something else.
> My thought, if this is the case, was to limit the echo link channel to
> only 1 connection, and keep it permanently linked to an echo link
> conference server, having people use that instead of my echo link node
> directly, but echo link doesn't seem to like it when people do that.
> Any help is appreciated. Feel free to write off-list if you feel this is
> off-topic.
> Thanks and 73
> de
> KE4DYI
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