The best replacement for audio interface is sound card.

The best alternatives to audio interface are rated as following:
★★★★★  sound card
★★★★★  mixer
★★★★  preamp
★★★  dac
★★  usb mixer
★  ad/da converter
★  headphone amp
★  usb microphone
★  multitrack recorder
★  usb
★  converter
★  digital mixer
★  di box
★  firewire
  pc sound card
  external sound card
  firewire interface
  pci
  mic preamp
  mixing desk
  usb audio interface
  d converter
  mixing console
  mic pre
  multitrack
  mixer recording
  pci interface
  onboard sound card
  firewire mixer

Your alternative for audio interface is not listed? Suggest!
Speaking about audio interface, one probably shouldn't forget about mixer.

Other search terms related to audio interface and their ratings are:
★★★★★ mixer
★★★★ pro tools
★★★ mic preamp
★★ monitors
★★ garageband
★ ableton
★ cubase
★ rocksmith
You have in mind a companion for audio interface and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of audio interface in all years. Click on graph for more.
audio interface
sound card
mixer