Root Notes and Key Zones on the EP-40, Explained
Two settings do all the work in an EP-40 multisample: the root note and the key zone. Understand both and your custom instruments will play in tune across the whole keyboard.
When you build a multisample for the EP-40, two settings decide how it plays: the root note and the key zone. Get them right and your instrument plays in tune from the bottom of the keyboard to the top. Get them wrong and notes drift sharp or flat. They're simple ideas once they click, so let's go through each one.
The root note
The root note is the key where a sample plays back at its original, unshifted pitch.
Say you recorded a note at middle C and set its root note to C. Press C and you hear the sample exactly as recorded. Press the D above it and the EP-40 shifts the sample up two semitones. Press the A below and it shifts it down. Everything is measured from the root.
That's why the root has to match the sample's actual pitch. Tell the EP-40 a sample's root is C when it was really recorded at E, and every note plays shifted by the wrong amount. The whole zone ends up out of tune.
The key zone
A key zone is the range of keys a single sample covers. An EP-40 multisample can have up to eight zones, each with its own sample and root note. Together they tile across the keyboard so that wherever you play, the nearest suitable sample sounds.
Within a zone, notes away from the root get pitch-shifted to match. The wider the zone, the more shifting happens at its edges, and the further you stretch a sample from its root, the less natural it tends to sound.
How they work together
Think of it as a relay across the keyboard. Each zone owns a stretch of keys. Each zone has one sample, anchored at its root note. As you play up the keyboard you move from zone to zone, and within each one the sample is pitched around its root.
More zones means less stretching per sample, so a more natural result. The cost is more samples, and more memory.
Setting them in EP-PatchStudio
You don't have to place all this by hand. Auto zone mapping assigns root notes and boundaries from your samples automatically, which is the fastest route to something playable. Manual mapping lets you drag the zone boundaries on the virtual keyboard and set each root note yourself, for when you want precise control.
Two rules of thumb
Keep zones narrower in the low end. Pitching a low sample up tends to sound worse than pitching a high one down, so give the bottom of the keyboard more, smaller zones.
And always match the root note to the real pitch of the sample. If a zone sounds detuned, the root note is nearly always the culprit.
Ready to build one? See How to Make Multisamples for the EP-40 Riddim.
Get started
EP-PatchStudio is free to download, with multisample creation included.