VoIP phone sound quality problem Pllycom VVX350

RomfordNavy

Having a problem with a Polycom VVX350 phone which just has a very dull sound whether via handset or speaker. I don't know if they are all like that but there is more treble on a landline. 

Cannot find any settings to adjust tone or internal sound quality.  Any suggestions?

DullGreyGuy

Which Codecs does your phone support? Which codecs does your VOIP provider support?

RomfordNavy

DullGreyGuy said:

Which Codecs does your phone support? Which codecs does your VOIP provider support?

I understand it is using G.711a but can't find anywhere to confirm that this is actually the case.