- Thanks, I saw USB Input but i don't think i detect any change in level when I adjusted just to check . Will try again and sounds like it should workYep, but it’s USB input level (not output), since were talking about the USB level coming back IN from the Axe FX. From the front panel go to Setup > I/O > page over to USB/AES > adjust USB input level, depending on what USB channels you’re using from Ableton. Using USB output 1/2 in Ableton (input 1/2 on the Axe), I found that looping with USB input at 0.0dB, it gave me the same level as the live guitar.