In article <ZFZmi.39288$ri2.28467@newsfe5-win.ntli.net>,
harrogate3 <nospam3@ntlworld.com> wrote:
>Anyone got any experience of audio quality issues.
>
>I have two accounts, one with Sipgate and one with voip.co.uk and a
>Sipura SPA2000 which I've only just managed to get working (since I
>changed from a Belkin to a Netgear router.)
>
>On Sunday evening when I got all working I was talking to a (local)
>friend using Sipgate, first through another voip provider and later
>through Sipgate (changes at his end.) He has 8Mb ADSL, I have 4Mb
>cable. The audio quality was good and clean albeit with a little low
>level hiss.

The hiss might be "Comfort Noise Generation" - something that's generated
locally to let you know that the call is still there. When a phone goes
totally dead then most people think the connection is broken, and as
this can happen in a VoIP system (some systems use 'silence suppression'
and stop sending data during quiet periods), then sometimes a little
bit of background hiss or noise is injected to keep you happy. Maybe
it's just a bit too loud on this system...

>However for incoming calls (I haven't yet loaded the Sipgate account)
>most calls to me from Sipgate got the voicemail, so last night I
>reconfigured to voip.co.uk. In two calls to my daughter on Orange, one
>from her to me and one initiated by me, the audio was distinctly
>choppy/burbly. There was no DAB-type bubbling mud, just the audio was
>clean but missing bits. If anything it was marginally better when I
>called her, and both times she was in the same (good signal) location.
>We both agreed that a conversation in the circumstances was
>impossible.

Choppy is probably packet loss. Did you have anyting else running at
the same time? Big download (or more likely upload?) Running any p2p
applications, etc?

>From what I have read here voip.co.uk is usually considered to provide
>a better service than Sipgate, especially in terms of audio quality,
>but my experience tends to suggest the opposite. Has anyone had a
>similar experience and/or can suggest how to improve the situation?
>Should I stay with voip and put up with the audio, or should I go back
>to Sipgate and try to find out why most incoming calls go to
>voicemail?

Do you have any sort of QoS controls on your router? (or is the SPA2000
acting as a router? I've no idea really what functions it has)

Sipgates server is (as far as I can tell) physically located in Germany,
so your data will go over the channel to Germany, then back to London
where they connect into their PSTN connector, so there's a lot of
Internet to go wrong or slow there, although saying that, when I trace
to sipgate from home, it goes over 12 hops, but to get to voip.co.uk,
even though it's in the UK, requires 11 hops (although it's 15ms 'closer'
in ping terms)

So make sure your own connection is as good as possible - QoS on the
router if possible (it's not perfect, but will help), and although I
use sipgate (occasionally), I'd stick to a UK service provider if at
all possible.

Gordon