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How Chop works

The idea behind the app: how a sample becomes slices, a pattern, parts and a song, and what follows from it.

Chop is built on one idea: a track is one sample, and everything it plays is made from pieces of that sample. If you know how the pieces fit together, every screen makes sense. This page explains the idea once; the other pages explain the controls.

From a sample to a song

Each row is made from the one above it.

A track holds one sample: a drum loop, a chord, a voice, a single hit, up to 20 seconds. There are eight tracks.
You cut the sample into slices. A slice is a piece of the sample between two cuts, with a number. Cutting does not change the file, and nothing changes in the sound yet.
The track plays a pattern made of blocks. A block says "play this slice here, for this long". At first there is one block per slice, in the original order, so the sample sounds as it was. Move, copy and remove blocks and you have a new beat from the same audio.
A track can keep four patterns, the variations A, B, C and D: the same slices in four different orders.
The song is made of parts. A part is one play of a pattern, placed on the timeline of the Multitrack. Put parts one after the other and the pattern repeats; leave a gap and the track is silent there.
The Mixer balances the eight tracks and sends them through your effects.

You edit in one place, and it plays in many

This is the consequence that matters most. Each thing is made once and then used by the level above it, not copied into it.

Change a slice (its pitch, its length, its filter) and every block that plays that slice changes, in all four patterns.
Change a pattern and every part of the song that plays that pattern changes.
A part has nothing of its own to edit except its place, the pattern it plays and its automation. That is why you cannot cut or rearrange audio on the Multitrack: there is nothing there to cut. Double-click a part and you are taken to the pattern it plays.

Example

Your drums play for 16 bars: eight parts of a two-bar pattern. The snare is too long. You shorten the snare slice once, on the Sample screen, and all eight parts play the shorter snare. You never have to repeat an edit.

When you do want one place to differ from the others, Chop gives you a level for it:

You want a difference	Use
One hit that sounds different from the other copies of its slice	The block's own settings: Change one block only
One bar of the song with a different beat	Another pattern: Variations A to D
One section where a control moves	Automation on that part
The same sample treated in a completely different way	A copy on another track: Copy a whole track

What belongs to what

Thing	Belongs to	Made on	What it holds
Sample	The track	Sample screen	The audio; Normalize and Reverse.
Slice	The track, shared by its four patterns	Sample screen, waveform	Where it starts and ends in the sample; its pitch, gain, reverse, envelope and filter.
Block	One pattern	Sample screen, lane	Which slice, where, how long; muted or not; roll; its own sound offsets.
Pattern (variation)	The track	Sample screen	Its blocks; its part markers.
Part	The track's row in the song	Multitrack	Where it is; which pattern it plays; its automation.
Track settings	The track	Sample screen, top panel	Bars, Timing, Fit, swing, voices; pitch, gain, reverse.
Mixer strip	The track	Mixer	Effects, EQ, sends, volume, pan, mute, solo.

Two ways of listening

Because a track is made in one place and used in another, Chop has two kinds of playback, and Return chooses by the screen you are on.

On the Sample screen you hear the track you are making: its pattern, alone, repeating. Mute and solo are ignored and automation does not play, because you are checking the material, not the song.
On the Multitrack and the Mixer you hear the song: all the parts of all the tracks, with mute, solo and automation.

Both go through the track's effects, its fader and the master, so a sound is the same in both. The details are in Play and listen.

Time is counted in bars

Chop does not find the tempo of a sample. Instead you tell it how many bars the sample lasts, and it works out the rest: if a loop is 2 bars long, it must fill 2 bars at any tempo. From then on everything is placed in bars and beats: blocks in the pattern, parts in the song, the grid, the swing.

This is why the first thing to do with a loop is to get its number of bars right, and why a sample that should ignore the tempo (a one-shot) has a switch for it. See Tempo, bars and timing.

Nothing is destroyed

Chop never changes your audio files. Cuts, reverses, pitch and stretch are instructions kept in the project.
Every edit can be undone, and a slice you silenced or a block you deleted can be put back.
The only files Chop writes are new ones: a piece you import from a long file, a recording, a resample, an export.

One sample per track: what follows

To use two different sounds, use two tracks. A kick and a snare from different files are two tracks; a kick and a snare cut from the same loop can stay on one.
To treat parts of one loop differently in the mixer (reverb on the snare only), copy the track into an empty one and keep different slices on each: Copy a whole track.
To turn a finished pattern, with its effects, into a new sample you can chop again: Resample a track.

Things with similar names

Three words appear in several places with different jobs. Knowing which is which avoids most confusion.

Four grids

Control	Where	What it decides
Grid	Toolbar	The step that things snap to when you move them: blocks and their edges, the Slice tool, part markers, parts, the cursor, the loop range, automation points.
Place: grid / free	Playback group	Whether this track's blocks and cuts snap to that Grid at all.
Note-value menu	Tool row, beside Chop grid	The step at which Chop grid cuts the sample, and the speed of a roll. It has nothing to do with moving things.
Swing 1/16 / 1/8	Playback group	Which steps the swing delays.

Three loops

Control	Where	What it does
Loop	Toolbar (`L`)	Whether playback repeats or stops at the end: the pattern on the Sample screen, the song on the others.
Loop	Playback group, Sample screen	Makes Play repeat the selected slice instead of the pattern, to work on one sound.
Loop range	Strip above the Multitrack ruler	Which bars of the song repeat while the toolbar's Loop is on.

A third word, "loop", is also what musicians call a sample that repeats: a drum loop. In this guide that is always "a loop"; the controls are "Loop" with a capital.

Four ways to reverse, five ways to silence

See Play something backwards and Mute, delete, silence, remove: the differences.