[Asterisk-Users] Soft phone sound quality help

[Rob Scott]

Anyone got any tips on improving sound quality on soft phones running
under Window XP SP2?
I have tried Xlite, SJPhone and Firefly.
They all seem to have significant sound quality problems. We have a
reasonable sized network of several hundred devices connected together
using Layer 2 switches, i.e. pretty dumb switches with no QoS.
I also have a Grandstream connected to the same switching gear.

The Grandstream sounds pretty good with very few drop outs or sound
problems on ulaw.
The soft phones all have problems although they get less when going to a
lower bandwidth codec, but then lower bandwidth gives you worse sound
quality too.

Is there any way I can improve sound quality on the softphones?
Or it is pretty well the general rule that they have poor sound quality?

It makes sense to install a softphone on each of the 200 desktops we
have but not to buy 200 Grandstreams or equivalent, and not to upgrade
all our network switches.

On the Asterisk side, jitter buffer is turned on with default settings.
TOS is turned on for SIP although I doubt the switches can do anything
with it.
I have played around with a lot of Asterisk settings but without getting
good results.