SECTOR Users Guide

©2014 Jonatan Liljedahl


You are encouraged to experiment and find your way through the SECTOR user interface. You should also read this users guide, you might come across something you didn't find by your own!

NOTE: Many buttons have additional functions when long-pressed.


Loops produced by Alex Matheu, Arovane, Richard Devine, Sonic Mayhem, Sunsine Audio


SECTOR is a stochastic sample slice sequencer for iPad.

The current sample (soundfile) is divided into a number of slices, called sectors. The number of sectors are adjustable and can be anything between 2 and 32.

There are three fundamental processes taking place, corresponding to the three tabs at the upper left:

Markov-chain matrix
Pattern sequencer

The first two controls when and if a certain sector is played. The last one controls how sectors are played.

Tap SND▽ at the upper right to show the sound menu, where you can load and import samples, adjust the number of beats and the number of sectors, and the auto-declicking fade time.

Tap PRJ▽ at the upper right to show the project menu, where you can load and save projects and configure MIDI clock sync.

You can import your own samples from AudioShare, pasting audio (general pasteboard), using "Open in" from another application, or by using iTunes FileSharing from a computer.

Tap ( RUN ) to start.


The markov-chain matrix connects each sector to any number of other sectors (but at least one).

Each connection has adjustable strength. A strong connection from sector A to B means there is a high probability that sector B will be played after A has finished playing. A weak connection means there are less probability.

When a sector has played, it can only continue with one of the sectors connected from it. The probability is distributed between connections from each sector, so if a sector has two equally strong connections going out from it, there is 50/50 chance it will choose one or the other.

In this way, sectors are chained together by variable probability. Each time a sector finish playing, a new decision is made according to its connections. A sector can also connect to itself, which will make it repeat.

Making connections

To adjust the connections between two sectors, first tap a sector to select it. The currently selected sector is highlighted in a brighter color.

Then drag on another sector to adjust the connection from the selected sector to the other sector. Drag out from the circle to make the connection stronger, drag inwards to make it weaker. Drag it all the way to zero to remove it.

Map tools

At the upper left, there are various buttons to perform actions on the connections.

( RND )
Randomize connections from the selected sector.
Long-press to randomize all connections.
( ALL )
Connect the selected sector to every other sector.
Long-press to connect all sectors to every other sector.
( CLR )
Connect the selected sector only to the next sector.
Long-press to do the same for all sectors.
( SH< )
( SH> )
Rotate the map.
( FLP )
Turn the map inside out.


The pattern sequencer overrides the sector choosen by the markov-chain matrix. This way, you can force certain sectors to be played at specific points in time, introducing rhythmical order in the chaotic ever-changing sequence produced by the markov-chain matrix.

Each pattern consists of 1 to 64 steps. Each step can be empty, or trigger any of the available sectors.


A step is not only on or off, but can have probability. 100% probability means the step will always produce a trigger and force the sector to be played. 50% probability is like a coin-flip, there is 50/50 chance that it will trigger.

Programming patterns

To program the pattern, select a sector by tapping it, then tap the pattern steps that should trigger the selected sector. Tap again with the same selected sector to clear the step.

Drag a step up/down to adjust the probability for that step.

When you select a sector, all steps with that sector will flash.

Sequencer tools

At the upper left, there are various buttons to perform actions on the pattern.

( RND )
Randomize the pattern.
( SHF )
Shuffle the pattern by swapping steps.
( CLR )
Clear all steps having the selected sector.
Long-press to clear the whole pattern.
( SH< )
( SH> )
Rotate the pattern.
( REV )
Reverse the pattern.


The warp process bends time during a sector by applying a transfer-function to the play-head. It affects how a sector is played, and can be used for a variety of effects and modulations such as stutters, speed-ups and slow-downs, reversing, ping-pong, etc.

Warp shapes

The warp shapes controls how the playhead travels along the sector. You can visualize it as time coming in at the bottom of the shape, bouncing against the shape curve, and going out to right of the shape.

So the first shape, a plain line, means that the sector will play linearly from beginning to end.

Warp slots

Each sector has four warp slots. Tap a sector to select it and show the warp slots for this sector.

Each slot contains one of the many different warp shapes, visible in the scrolling menu to the left. First select a warp slot by tapping it, then tap a warp shape to load that shape into the selected slot.

The shapes can be reversed by tapping the small arrow beneath each warp slot.

Warp probabilities

Each slot has adjustable probability. When the sector plays, it chooses one of the warp slots depending on their probabilities, and applies the associated warp shape. There is only one warp active at any time.

The probability is distributed among the four slots and an additional invisible slot that keeps using any warp that is currently active. Setting the four slots at 0% probability leaves 100% to this invisible slot.

Warp tools

At the upper left, there are various buttons to perform actions on the warps.

( RND )
Randomize all warp slots for the selected sector.
Long-press to randomize all sectors.
( CLR )
Clear warps for the selected sector.
Long-press to clear warps for all sectors.
( CPY )
Copy the warps for the selected sector.
( PST )
Paste warps into the selected sector.
Long-press to paste into all sectors.

Memory slots

At the bottom left of the screen, you'll find the memory slots.

M 1 2 3 4
S 1 2 3 4
W 1 2 3 4

There is one row of four slots each for the MAP, SEQ and WRP processes.

Each memory slot contains a full configuration for the related process, for example a pattern for the pattern sequencer. Tapping a slot switches instantly to it.

The currently selected slot is indicated by a circle.

Swipe a slot upwards or downwards to switch all three rows at the same time.

Copy & paste slots

Tap and hold a memory slot to show the copy/paste menu, which allows you to copy a slot and paste it into another slot.

Previewing sectors and warps

While SECTOR is stopped, selecting a sector will play back that single sector and then stop.

Also, tapping a WRP slot or choosing a new warp shape will preview the currently selected sector with that warp applied.

Manual triggers

At the lower right there are four manual trigger buttons.

( T01 ) ( T02 ) ( T03 ) ( T04 )

Tap a trigger to force which sector should be played next, ignoring the control of the markov-chain matrix and pattern sequencer.

To associate a sector with a trigger, tap and hold the trigger and then tap a sector. The color and number of the trigger will change to reflect the current association.

Tempo and sync

At the top of the screen is the tempo control, in beats per minutes.

Drag it to change the tempo in whole numbers. Tap the arrows to make fine adjustments to the tempo.

Playback rate

By default, changing the tempo also changes the playback rate, like on a tape recorder. Tap the link button at the top center to decouple tempo and playback rate. When decoupled, you can change both individually. Sectors are zero-padded as needed when increasing the playback rate.

The actual speed relative the normal tempo of the soundfile is shown in the sound menu. Tap the speed button to reset the tempo to the original value of the soundfile.

To give a correct tempo display, the number of beats in the soundfile must be set correctly. Set the number of beats in the sound menu.

MIDI clock sync

MIDI clock send can be configured in the MIDI config page in the project menu.

Enable SEND ALWAYS to send clock even while stopped, so that slaves can tune in on the correct tempo before starting. Note that SECTOR will remain running in background while sending clock.

Follow IAA host

While connected as an inter-app audio node, SECTOR starts and stops with the host. Tap the ☍ symbol in the host transport panel to turn follow-host on or off.


Tap the record button to start or stop recording. The actual recording state changes at the next sequencer pattern cycle, and allows sample accurate recording of new loops.

The small orbiting indicator shows the current sequencer pattern position. While waiting to change recording state, the indicator changes to a shrinking arc line to indicate the count-down.

Manage recordings

You can manage your recordings by tapping Recordings in the SND menu.

Tap a recording to open the menu of choices. You can load the recording back into SECTOR as a loop, export it to AudioShare, use AudioCopy to copy the loop for pasting into another app, or open the loop in another app.

Step-recording sectors

While SECTOR is stopped, you can record a string of sectors by enabling recording and then tapping sectors in any order. As each sector is selected, it is played and added to the recording. Tap the record button again to stop.

Sharing projects

Tap the share-button at the top right of the PRJ menu to share the current project. You will be asked to give the project a name.

You can send the project to another app such as Dropbox, or email it to a friend.

If the project uses a custom sample, the audio will be embedded into the project.


Feel free to email me with any questions or problems.

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If you like the app, please consider giving a review in the App Store, it really helps!