Also, did you read this part on pager 18 of the ID Core Handbook:
USB Recording Level – Tap + Gain
As stated in the USB Audio section (see page 15), the output level of the USB audio
signal from your ID:Core amplifier can be controlled independently of your amplifier’s
speaker volume by holding down the Tap switch (11) whilst turning the Gain control
(3) on the front panel.
I hope this helps.