Chop, split and stretch · Koala Sampler guide

5.1IntermediateNeeds Samurai

Chop a sample across your pads

AUTO-CHOP cuts one sample into pieces and gives each piece a pad, so you can replay a break or a phrase in any order you like. If you’d rather not spend the pads, Chopper does a similar job from a single pad, and the table below will help you choose.

AUTO-CHOP or Chopper?

	`AUTO-CHOP`	Chopper
Where the slices go	Each chop goes on a free pad of its own	All the slices stay on one pad
How you play them	Tap the pads, one chop per pad	By key or MIDI note, by how hard you hit, at random or in order
Choose it when	You have pads to spare and want to handle each chop as its own pad	You don’t want to use up a bank of 16 pads, or you want those trigger modes
If you change your mind	`KEEP ORIGINAL` holds on to the full sample	`EXTRACT SLICES` puts the slices on pads later, and `CONVERT TO SAMPLE` turns the pad back

Chop a sample

Select the pad and tap EDIT, then open TOOLS and tap AUTO-CHOP.
Choose a mode: TRANSIENTS, EQUAL or LAZY.
In TRANSIENTS or EQUAL, swipe the chops bar to get more or fewer chops. If the bar turns red, you’ve asked for more chops than you have free pads.
In LAZY, place your markers instead: see below.
Set the options below.
Tap CHOP to make the cuts, or CANCEL to back out.

Which mode to use

Mode	How it cuts	Use it for
`TRANSIENTS`	Finds the transients in the sample and cuts there.	Drum breaks and other short samples.
`EQUAL`	Cuts the sample into parts of the same size.	Loops, or breaking a long sample into smaller chunks.
`LAZY`	You place the markers yourself while the sample plays, the way you would on an MPC.	Choosing the cuts by ear.

Work with markers in LAZY

Switch to LAZY, start playback with the play button, and tap the marker button next to it wherever you want a cut.
Tap the waveform to audition the chops.
Drag a marker along the bottom to move where its chop starts.
Tap in the blue stripe under the waveform to add another marker.

Gestures

Swipe the chops bar: Changes the number of chops.In AUTO-CHOP
Tap the waveform: Previews the chops.In LAZY
Drag a marker: Moves where that chop starts.In LAZY
Tap the blue stripe: Adds a chop marker.In LAZY

Options in the chop window

KEEP ORIGINAL: On: the full sample stays on its pad. Off: the first chop takes its place.
CHOKE GROUP: Puts every chop in the group you pick, so they cut each other off. See Let one sound cut off another.
ONESHOT: Sets every chop to one-shot playback. See Make a pad play through, play while held or play backwards.
PLAYTHRU: On: every chop plays on to the end of the sample. Off: each chop plays from its own marker and stops at the next one.

From the community

Koala Sampler Tutorial - EP 11 - Exploring The Auto Chop (Samurai) Functions
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Slicing samples across pads with Samurai’s auto-chop. It predates Chopper, the non-destructive alternative.

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The developer explains time stretch, auto-chop and the piano roll. It’s from January 2021, so later Samurai features such as Chopper and Quokka aren’t in it.

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How one producer really starts a beat: hand-chopping a break, shaping drums, choke groups, swing and a chromatic bass line.

Samuraielf audio — What the Samurai add-on unlocks: time stretch, piano roll, auto-chop, 3-band EQ, the Quokka synth and MIDI out.

5.2IntermediateNeeds Samurai

Play slices from one pad with Chopper

Chopper keeps all your slices on one pad and turns that pad into an instrument, with a different slice on every note. Reach for it when chopping onto separate pads with AUTO-CHOP would eat a whole bank, or when you want to trigger slices by velocity, at random or in sequence. You aren’t locked in: you can move the slices onto their own pads later.

Turn a pad into a Chopper

Select a pad that has a sample on it and tap EDIT.
Open TOOLS and tap CONVERT TO CHOPPER. Slice markers appear on the waveform.
Drag the CHOPS bar to get more or fewer slices.
Tap the waveform to audition the slices.
Set SLICE MODE, TRIGGER MODE and the switches below.
To go back to a normal pad, open TOOLS and tap CONVERT TO SAMPLE.

Gestures

Drag the CHOPS bar: Changes the number of slices.On a Chopper pad
Tap the waveform: Previews the slices.On a Chopper pad

Slices and playback

SLICE MODE: AUTO puts the slices on the sample’s transients. EQUAL cuts it into even parts.Range AUTO, EQUAL
SENSITIVITY: In AUTO, controls how many slices Koala finds.
ONE SHOT: On: a slice runs to its end from a single tap. Off: it sounds only while your finger stays on the pad or key.
MONO: On: slices can’t overlap, so starting one silences whichever was playing. Off: they’re free to ring over each other.
PLAY THRU: On: a slice ignores the next marker and carries on to the sample’s end. Off: the next marker ends it.

How TRIGGER MODE picks a slice

Mode	Which slice plays	Good for
`NOTE`	A different slice for each key in keyboard mode, or each MIDI note.	Playing chops like an instrument. See Play a pad like an instrument.
`VELOCITY`	Depends on the strength of your hit on the pad.	Getting different slices out of one pad by touch.
`RANDOM`	A random one, on every hit.	Variations you wouldn’t have played yourself.
`NEXT`	The next one along, in order, on every hit.	Tapping through a phrase at your own speed.

Extra entries in TOOLS

EXTRACT SLICES: Copies each slice to a free pad of its own, which gets you the same layout as AUTO-CHOP.
EXTRACT PATTERN: Creates a sequence that triggers the slices in the order they came in the sample. Rearrange them in the piano roll to flip it.

From the community

My 2026 Koala Sampler Workflow: 3 Features That Changed How I Make Beats
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A beat from scratch on the current app, using Chopper, the improved stem splitter, an AUv3 synth, resampled bass, bus effects and arranging. Sponsored by Synido.

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The Chopper instrument, filmed days after it arrived in update 1.4145.

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A five-minute method for getting new drum patterns out of a break with a Chopper technique, then resampling the result.

5.3Basics

Pull a sample apart into stems

SPLIT STEMS uses neural networks to break a sample into as many as four parts: DRUMS, VOCALS, BASS and OTHER. Use it to lift a vocal, get at the drums under a song or strip a track back to make something new.

Split a sample

Select the pad and tap EDIT, then open TOOLS and tap SPLIT STEMS.
Turn on each stem you’re after.
Flip the quality switch to FAST or HI QUALITY.
Leave MERGE SELECTED off to give each stem a free pad of its own, or switch it on to mix them into one new pad.
Tap SPLIT, and give it time. It’s demanding work for a phone.

Options in the split window

FAST: The quicker of the two neural networks. You give up some quality for the speed.
HI QUALITY: The slower network, with much cleaner stems.
MERGE SELECTED: Puts all the stems you chose on a single new pad. It’s the quick route to an instrumental (everything but VOCALS) or an a cappella (just VOCALS). See Make an instrumental or an a cappella.

From the community

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A short 2022 demo of stem splitting. The high-quality splitter arrived in version 2.0.10, so results may differ from what you hear here.

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Compares the new high-quality splitter with the old one, with Logic Pro and with real stems, so you can judge how much it helps.

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JFilt on the new Koala plugin for Mac: downloading it, dragging samples into a DAW, splitting stems and building a beat. From October 2026.

5.4IntermediateNeeds Samurai

Lock a sample to your tempo

Time stretching makes a sample fit your song. You say how many beats or bars it should last, and it plays over exactly that length at your song’s tempo. It can also change pitch independently of timing, though REPITCH deliberately ties the two together.

Stretch a sample

Open the sample editor and set the red area to the part you want.
Tap STRETCH. A bar count appears along the top of the selection, and playback locks to your song’s tempo.
Tap the bar count to open the TIMESTRETCH window.
Set the length you want the selection to last: 1 BEAT, 2 BEATS, 1 BAR, 2, 4, 8 or 16 BARS. CUSTOM lets you enter some other count of beats and bars.
Pick one of the five modes below. Each has its own sound.
Tap PREVIEW to check the result before you close the window.

The five modes

Mode	What it does	Pick it when	Plays chromatically?
`MODERN`	Stretches smoothly and cleanly.	You want the safe choice. It suits most material.	No
`RETRO`	Copies how classic samplers stretched audio, with a granular sound.	You want the character of an old sampler.	Yes
`BEATS`	Works from the transients in your sample, using chops and loops to lengthen or shorten it.	You’re stretching a drum loop.	Yes
`REPITCH`	Ties length to pitch, the way a record does when you speed it up.	You want the pitch to move with the speed.	No
`CYCLIC`	Recreates a retro cyclic stretch.	You’re after the sound of 90s jungle.	Yes

Planning to chop the sample as well? Set the stretch first, because AUTO-CHOP bakes it in.

From the community

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Seven minutes on the time-stretch options, which need Samurai.

Samuraielf audio — What the Samurai add-on unlocks: time stretch, piano roll, auto-chop, 3-band EQ, the Quokka synth and MIDI out.