voice quality

I have Sony Ericsson z500a and i have always had sort of bad voice quality, making it very difficult to hear what people say. Could it be the Cingular network or the problem is with my phone? I live in the northern suburbs of Minneapolis

it's definitely yourphone. it's notorious for its bad reception. It's like this with Sony Ericsson z500 and any LG phone, although Sony Ericsson z520 has quite a good quality. Overall, nokia phones offer best reception. I'll advise to go to a cingular store. They will probably update your sim and if it still doesn't work they will switch out your phone for a known better reception one.

if i were you i would try a newer phone and probably a new sim.