i’m not getting any sound from my headphones, I’m completely plugged in. I have a Sonic Port tm VX unit for listening and recording on my Compaq Presario laptop. just bought it w/desk top stand, comes with usb cable. I play harmonica and wish to record to laptop hardrive and using audacity software…see if you can help me, thanks in advance! Laptop uses Windows 8 professional. 
Connect the Line 6 Sonic Port VX to the computer then restart Audacity.
Select the VX as recording and playback device in Device Toolbar.
Use Mixer Toolbar:
to adjust the recording and playback volume.
By the way some users are not getting Line 6 devices recognised by Audacity under Windows 10, so if you were planning to upgrade to Windows 10 it may be wise to defer until the situation is clearer.
Gale