Some background

A week ago, I polled fellow mashup artists to find out how they identified keys and which databases they used.

Several different websites and programs for finding keys and chord progressions were listed, including Tonalify, Tunebat, Songdata.io, Mixed In Key, Hooktheory, and Ultimate Guitar.

Most of you may look at these websites and programs and think they all use different algorithms.

The truth? Searches for songs using Tonalify, Tunebat, and Songdata.io all query Spotify's database of keys.

And what's worse, Spotify key accuracy places dead last (< 33%) among leading automated key detection algorithms again and again and again.

With the ability to search the key of any song on Spotify, it's no wonder Tunebat keeps getting suggested. We can all do so much better, especially with hit music that a lot of us use.

Initially, this was going to be a much longer post. However, I quickly realized that the r/mashups audience may not know a lot about music theory, so I wanted to focus on the tools, and maybe create a separate post from this one going into details of my key detection workflow.

Key and chord progression databases

If you plan to use DJ software and online stores for automation, consult this list for the most accurate analysis tools (comparison done in 2021).

When it comes to online databases, I tend to use the following in this order, depending on whether the song has been analyzed:

• Hooktheory (TheoryTab)
• Musicnotes
• Ultimate Guitar+Hookpad
• Mixed In Key
• Beatsource
• Any others (including Discord servers and YouTube tutorials)

Hooktheory (TheoryTab) [Free]

Hooktheory (TheoryTab) is by far the best of those listed, because it is the only online database of keys that also includes the common major scale modes (Mixolydian, Lydian, Phrygian, etc.), along with other common modes (Harmonic Minor) and chord progressions. It even includes key changes.

Think of it like a Wikipedia of song analyses, made by music theory experts. A lot of current hit music on there.

MusicNotes [Free preview, Paid for full sheet music]

MusicNotes contains sheet music of popular songs and pieces for sale, written by composers and arrangers. The key signature is provided. You won't be able to see the full arrangements without purchasing, but the first page is available, with portions of other pages visible.

If the track is repetitive enough, you can get a good sense of the chord progression and notes outside the key signature (which can be a clue for modes). For example, if you notice a minor key signature but also see # (sharp) markings on sevenths in the piece, you know it's harmonic minor. Useful if you know how to read sheet music.

Identifying modes this way is a separate music theory discussion.

Do note that while key changes are accounted for, quick changes in tonal center may not be, so you'll probably see a bunch of # and b markings for notes outside the key signature.

Ultimate Guitar [Free, with pro analyses paid]

Ultimate Guitar contains chord progressions that musicians come up with for a lot of popular and not so popular music. No keys or modes given though. While not exact the progressions listed tend to be pretty accurate. Pro tip: Switch to piano mode when looking at analyses.

What I would then do is plug in the chords into Hookpad, which can then tell you which chords belong to a specific key or mode as you're adding them in.

Mixed In Key [Paid]

Mixed In Key is considered the most accurate automated key analysis tool according to several comparisons that have been done with big music databases using major and minor keys*. No modes or key changes though, and it's a paid key detection tool.

For accurately identifying keys for large music collections, Mixed In Key is well worth the price.

* Note that relative keys were marked as correct

Beatsource [Free]

Beatsource leans more towards hit music and especially hip-hop that Hooktheory and MusicNotes do not tend to touch. Not as accurate as the others, but it tests well for current hit music.

Final thoughts

Before you use any key information from these databases, please use your ears to convince yourself that the key/mode identified is accurate.

To do so, go into your DJ software and test the pairing with the key you found before opening up your audio editor or DAW and trying out the pairing.

That all said, a lot of the information you'll find can be quite overwhelming for those who don't know a lot about music theory.

If you're unsure on a key, chord progression, or whether a mashup idea actually works, please feel free to ask us by creating a [Discussion] post or posting to Feedback Friday.

We're happy to help.

Thank you all.