I see a constant
stream trickle of questions asking how to connect instrument X to audio interface Y. (I say Y, but it's usually the Focusrite Scarlett 2i2). The problem usually stems from unfamiliarity with, or uncertainty about, either:
- guitar vs. microphone vs. line level signals
- balanced vs. unbalanced signals
- mono vs. stereo signals
- headphone vs. line outputs
- direct monitoring vs. loopback monitoring
- ground loops
Unless there is already a Q&A that covers these topics, I propose that we create one, so that in the future we can close new questions asking for this kind of advice as a duplicate.
I suggest we keep it simple, with limited jargon (except to explain the jargon that is printed on the instruments and interfaces), and use examples of a few popular interfaces such as the Focusrite Scarlett and Behringer UM range.
After reading the comments, and thinking about what the Q&A would look like, I agree that "how do I connect anything to my audio interface?" is probably too broad. What people will be searching for will be more specific. I think it's logical to split up the question into these three categories:
- How do I record my guitar/bass to my computer?
- How do I record my synth/digital piano to my computer?
- How do I connect a microphone to my audio interface?
The guitar/bass answer could cover high impedance inputs, what to do if your audio interface doesn't have one, output from effect pedals or multi-fx, etc.
The synth/digital piano answer could deal with line outputs vs. headphone outputs, recording in mono or stereo, connecting unbalanced outputs to balanced inputs, etc. And it could also function as a catch-all answer for questions about recording any device with a line or headphone output, like a dj mixer or an emulated speaker output on a guitar amp.
The microphone answer could deal with dynamic vs. condenser, phantom power, balanced vs. unbalanced signals, external pre-amp vs. the interface's pre-amp, etc.
All the answers would of course have similar parts about how to identify the different inputs on the audio interface, outputs on the instrument, cables and plugs, and maybe also direct vs. loop-back monitoring, ground loops, etc... but these could be tailored to the specific question.