Finding The Key of a Song

There's a few ways to determine the key of a song, each of which depends on the assets you have available - The most powerful of which, your ears!

Tone Deaf

All things being equal, the key of a song can usually be figured out quite easily if you can distinguish between sound pitches (whether a note is higher or lower than another). Some people can't but that doesn't necessarily mean your music-making days are over - Beethoven was deaf remember! It just means you need to rely on other cues like sheet music, software, etc...

If you're not technically deaf, but are basically "tone-deaf", the quicker you can be honest with yourself and admit it, the less frustration you'll encounter (Don't be one of those bad X-Factor contestants).

Find the Root Note

Finding the root note is a good place to start.

Since I guess most, if not all of you, own a sequencer, the "simplest" way of finding the song-key (probably) is to import the sample and then create a MIDI channel, with a Piano or plain Bass guitar as its assigned instrument. Place the loop locators around, say, the first 4 bars of your sample (timing isn't important at this stage) and then, either with your keyboard or pencil tool (within your sequencer's MIDI editor), just tap (or draw) single notes until you hit the right one.

You'll know when you hit it: Usually - but not always - you're looking to match the first root (bass) note of the loop. Once found, keep the note playing until it sounds out of tune - You've now found the next key-change in the song: Now repeat until you have found all your root notes for each key-change.

Typically, in a lot of moden music these days - particularly dance music - there can be 2, 3 or 4 key-changes.

[TIP: The root note, or key note, is (often) much like the downbeat, ie... it (usually) comes around at the start of the loop in predictable fashion.]

If you still can't find it, then you'll be reliant on technology such as Melodyne and the likes, which can tell you the note-values of individual notes... but then, if the first suggestion gets you nowhere you should perhaps look for another hobby!

Chords

Of course, having the root note doesn't mean everything we play from this point on will sound right - We still haven't discovered if the key is a Major, a Minor 6th or whatever... But building chords is the subject for another day.

What you have learnt today is a bloody good start. Once you know you have a root note of [E], followed by another [A], you have the essential building-blocks to kick-start your composition (or remix).

Off-Beat Gotcha's

A couple of things that might trip you up are, for instance, when the part we are sniffing, actually begins (say) an 1/8 note before the first beat. The passage may be in the key of [E], but the artist tries to be a bit clever by starting with a [D] on the last off-beat of the previous bar (or preroll if we're at the beginning of a song), then he/she resolves to [E].

Another tricky customer can be detuned instruments, particularly synthesiser basses: It could be the case where the bass timbre has a couple of oscillators applied to it, one detuned by a 3rd (for instance). They can be tricky because sometimes it sounds right, sometimes it doesn't (usually in solo mode), particularly if you're comparing against another instrument like a Piano.

Trial and error is key. In the case of the bass (above); when comparing, try a higher octave. Once you think you've nailed it, drop it back to the correct octave again.

Dunno if that's of any help to anyone - I'd seriously advise anyone to try and figure it out for themselves as an exercise - The more you do it, the easier and quicker it gets.