After shifting from NEC to VOIP setup, some users said that the sound quality is a bit muffled. This is my current setup: 3CX 16SC Pro 2CPU - 8GB RAM - SSD drives - dedicated gigabit port (Hyper-V VM) Cisco 2960-S 48 port POE (Vlan 1 data and Vlan 100 voice) Yealink T46G handsets - G722 is the preferred codec Cyberoam50ing - Gateway with SHDSL and 2x ADSL backup. The 5MB SHDSL is dedicated to VOIP traffic with QoS for 3CX traffic. Engin Australia - SIP trunks provider What could be the cause of the problem? Is it 3CX, yealink or sip provider? Appreciate any response.