The OCTA-CAPTURE's XLR (Microphone) Inputs 7 and 8 were designed to take a little bit higher input volume levels than Inputs 1 though 6--to have plenty of headroom when recording loud sources such as a bass/kick drum. Because of this, incoming audio signals into Inputs 7 and 8 will be 6dB lower in volume than Inputs 1 through 6.
Below are the specifications for the OCTA-CAPTURE's XLR inputs:
NOMINAL INPUT LEVEL:
Input Jack 1—6 (XLR type)
-56 to -6 dBu
Input Jack 7—8 (XLR type)
-50 to +0 dBu
MAXIMUM INPUT LEVEL:
Input Jack 1—6 (XLR type)
+10 dBu
Input Jack 7—8 (XLR type)
+16 dBu