Is your model the "x" version or not. Whether you are using the ir or not may be immaterial; it could be that you need to go in and raise the turn on volume.
Xantech.com has the manual for this amp. You may wish to check that.

I can't tell if you are an installer or the end user; you may wish to check with the tech support department at Xantech or the company that supplied it for you.