Bad Voice Fidelity

Hello I’m using asterisk 1.4 on kubuntu 7.04, my asterisk is in a ISP and it has Qos (Quality of service). In my house I have another ISP, and I use an ATA grandstream (all the users use that). The voice is heard really badly, I tried diferent codecs and the best is ilbc. I think it could be the delay. When i put sip show users asterisk shows (the user 104 has 73ms, in that good?)::

104/104 D N 5060 OK (73 ms)
103/103 (Unspecified) D N 0 UNKNOWN
102/102 (Unspecified) D N 0 UNKNOWN
101/101 D N 5060 OK (44 ms)

I think that if the problem is the delay it could be improved by a kind of buffer or somethink like that, have someone that problem??

Thanks in advance

73 ms is not a problem at all. Try using the G729 codec. Also try using your device in another location and see what happens. Another problem may be your internet at home. Are you downloading anything as you make the call. When you have such an issue the only real way to figure it out is by process of elimination.