Tuning is matching the pitch of an instrument or a voice to a reference. It covers not only tuning guitar strings before playing but also, in a broader sense, aligning the pitch of multiple instruments and pieces of material.
The basic idea
A = 440 Hz is the most common reference, though some instruments and works use a different one. If the reference is not consistent, things can sound muddy together even when each part is in tune on its own.
Its role in writing and performing
Tuning before recording is the foundation of a performance. When using several loops and samples in a DAW, checking that they match the key and the pitch of the song reduces the sense that something is off.
How to check it in a DAW
Use a tuner plugin or a spectrum display to compare the reference note with your material. When using pitch correction, listen to make sure it does not become unnatural from over-correcting.
How it differs from related terms
Tuning is the act of matching a reference, while pitch is the height of a sound itself. Intonation can refer to the accuracy of pitch during a performance.
Matching the reference first, then checking that it sounds natural within the song, is the safe order.
