T54W inconsistent volume issues

[ResponseIT]

Hi,

This is a new install of 14x T54w handsets on a 3cx system.

There are inconsistent issues with the volume (loudness) of calls. This is not a one-way audio problem. The call audio comes through, but it's very quiet and the handset volume has to be turned up to full to be usable. On other calls the handset volume only needs to be at 50% to be usable.

There is no stuttering, distortion or dropout that would indicate packet loss.

The issue happens intermittently in both directions, on multiple handsets, and can affect both internal and external calls. When it happens on external calls, the T54w user can hear the external caller fine, but the external caller complains that the T54w user is too quiet.

This is the first install of T5x handsets that I've done, but i've deployed hundreds of T4x for other customers and never seen this problem before!

Any suggestions?

Thanks,
Dan