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What is it?

A lightweight tracker plugin for REAPER 5.x and up. Hackey-Trackey is a small tracker for visualizing and editing MIDI data within REAPER. Originally developed to mimick the pattern editor of Jeskola Buzz, this tracker is meant to enable MIDI note entry and effect automation in a tracked manner. You can see it in action here: Hackey Trackey in Action

What is it not?

A sampler. Hackey-Trackey does not handle sample playback. For this you would need to add an additional VST that handles sample playback. Have a look at ReViSiT or linking a dedicated tracker program such as Renoise to REAPER if this is what you seek.

Small disclaimer

Hackey Trackey is still actively being developed. Not all planned features are finished yet and there may stil be bugs. Be sure to check back in the future if you want to be kept up to date with the latest features. Basic tracking functionality works (note entry, FX sequencing) and directly updates MIDI and automation data.


With Reapack

Add it in your Reapack repository list: Eventually, the plan is to make the tracker part of the reapack scripts repository, so that this separate repo is no longer necessary.


  • Press ? or select Actions > Action List
  • click the ReaScript: Load button

How do I use it?

Select a MIDI object and start the script. Note that scripts can be bound to shortcut keys, which I'd recommend if you're going to be using it. This short tutorial assumes the default keymapping, but others are available in the options menu. In the default layout, options can be brought up with F11 and a small help file indicating all the options with F1 (same in all layouts).

Using Hackey Trackey

What MIDI channel is used?

The plugin remaps your MIDI data to different channels. New MIDI data that was not tracked has to come in on channel 1. Hackey trackey recognises notes which have not yet been assigned to a column by their channel. Note also that by default the tracker remaps everything to MIDI channel 1. The output channel (OUT) can be changed with the F1 (down) and F2 (up) keys in the default layout or by clicking the OUT field
and dragging the mouse up or down. Setting the output channel to zero (displays as C) maps each column to a separate MIDI channel. Note that column one goes to MIDI channel 2 and so forth.

Pattern info

Important use notes

It is recommended to change the size of MIDI items from within Hackey-Trackey rather than by dragging them in REAPER's sequencer. You can do this by clicking the pattern length indicator in the bottom left and entering a new length. The reason for this is that HT will create new automation objects if it doesn't find ones of appropriate length that are correctly aligned. If you wish to edit the MIDI items in REAPER, then close the instance of Hackey Trackey, resize the item and glue the item before reopening HT.

Mouse operation

Hackey Trackey is designed to mostly be used via keyboard shortcuts. That said, some mouse interaction has recently been added. You can click and drag Resolution (Res), Octave (Oct), Advance (Adv), Envelope (Env) and Out channel to set these values. Note that since the resolution or ticks per beat can be a destructive operation, this one needs to be confirmed by clicking, dragging and then confirming the new selection with the outer mouse button while still holding the left mouse button.

Recording status can also be toggled by clicking it, and the pattern size can be changed by clicking the pattern size. Removing the current size and confirming with return.

Can I automate parameters?

Yes! Parameters for which envelopes are active (see automation panel in image below), will automatically show up in the tracker. The tracker will store the tracked points in an automation take. Ctrl + Shift + Up/Down changes how the values in the column will be interpolated. Using FX

Can I send MIDI CC commands?

Yes! There are two ways to work with CC commands. The first is a single column mode (which is good if you typically only use a single command or use commands) sparingly. Or multicolumn mode.

Single column mode:

This is the default. The first two columns denote the CC command, the last two the value that's being sent.

Multi-column mode:

This is activated when expanding the mod column (expand by going to the CC column and pressing CTRL + +). Now, every CC command type gets its own channel. You can remove a column with CTRL + Shift + -, which will delete all the CC data in that column as well as remove the column. You can add a new column with CTRL + Shift + + after which you have to enter a numeric value and hit RETURN. Custom names can be added in the CC column. Hint: If you want this to be the default mode, then edit the script and change tracker.modMode to 1.

The CC commands don't interpolate?

Yes. They do not and this is considered out of scope for the tracker. If you wish to interpolate CC commands, I suggest you use ReaControlMIDI to map the CC commands to an FX envelope. These you can then use in the same way as the parameters.

I do not hear the notes I play? Can I change it such that I do?

If you want to hear notes you play, remember to arm the tracker by hitting CTRL + R. Note however, that this alters the recording status of your project. If you wish to always have HT enable recording, then enable "Always Enable Recording" in the options menu.

The default theme is not my style. Are there any others?

Yes, there are various themes to choose from. See the options menu (F11). Themes

The latest theme is Sink, but it relies on installing a font first which you can get here: Sink

Can I do step sequencing from my MIDI device?

Yes you can! Enable track from MIDI in the options. This will inject a JSFX on the track in question which will track the incoming MIDI and send it to HT. Note that this will disable any playback preview within Hackey Trackey however, as that would otherwise create an infinite loop.

What is advance to next note mode?

Advance to next note mode is a mode in which the cursor always advances to the next note in on the column you're working in, rather than a fixed number of steps. When you get to the end of the pattern, it loops back to the start. This allows you to quickly audition different potential melodies for a particular rhythm. You can quickly toggle it with CTRL + T.

Note that an additional feature of advance to next note mode is that if you select a region on the pattern, the method will constrain the advance method to stay within that region.

Can I change the pattern length from the tracker?

Yes. Click the pattern length indicator in the bottom left of the tracker. You can enter a new value here.

All my notes sound very staccato? What's going on?

By default, tracked notes do not overlap. However, for some purposes, overlap may be desirable (some monophonic VSTs interpret this as glide/legato mode). For this, one can use the column L. Setting 1 in a row here, means that this note will be glided into. This is implemented by simpliy stretching the previous note. Legato is only applied to channel 1 in the tracker. Note that performing a legato from and to the same note will result in the second note not displaying in the tracker. This is not a bug, but a workaround to fix note OFF issues with the resulting MIDI item.

Can I rename patterns?

Yes, simply hit CTRL + N and type a new name followed by ENTER.

How does navigation work?

You can move left to right on a single track with CTRL + Left/Right.

I need a higher resolution?

You can edit the row resolution by entering CTRL + ALT + Up / Down. You will then notice that the resolution bit in the description bar becomes red. This means it is not committed. If you then hit commit (Ctrl + Alt + ENTER), the resolution will change.

Can I use note delays?

Yes, but there is a catch. For note delays to work reliably, your MIDI settings have to be set in such a way that each row is a multiple of 256 MIDI pulses long. Otherwise, roundoff errors will occur which cause values to shift as you enter them.

You can set these in Options => Preferences => Media/MIDI => Ticks per quarter note for new MIDI items. The default here is 960, but 1024, 2048 or 4096 is recommended for Hackey Trackey. Once configured correctly, you can open the note delay column for any note by simply hitting CTRL + + for that column.

Can I enter note lengths?

Yes you can. Hit CTRL + + twice on a note column to bring up the note length panel. This will allow you to edit the duration of the last tick of the note at a subtick level. The same caveats as with note delay apply.

What is this Harmony Helper thing?

Release 1.30 saw the addition of the Harmony Helper, this is an extension of Hackey Trackey to facilitate easier use of melodic scales. You can toggle the Harmony Helper by pressing F9.

The Harmony helper presents you with a selection of root notes and modes. You can pick your desired musical key by selecting the root note (top row) and scale (left column). After selecting a key, you are presented with chords that are present in that key.

If the track is armed (denoted by the red [REC] label), it will play the chord you click. To arm the track press CTRL + R.

To insert a chord from the harmony helper, press control while clicking the chord. Inversions can be obtained with other modifiers. Holding ALT will trigger an inversion of the first note, while SHIFT inverts the second.

Once a key is selected and the harmony helper is active, notes will transpose in a key-aware manner when transposed. Diatonic notes will map to diatonic notes when transposed, while accidentals will remain accidentals (as far as this is possible without an awareness which notes are flat or sharp).

To change the root of the key of a selection, simply select the notes and invoke CTRL + ALT + SHIFT + + or - for transposition up and down respectively. This will also update the root note in the harmony helper.

Harmony Helper

Is this repository reapack compatible?

Yes. Just add:

I'm missing sample offset.

Sample offsets have to be achieved via the VST or JSFX and mapped onto reaper FX.


Step one.

After loading an instrument hit the edit instrument button. If the instrument is locked then I'm afraid you cannot achieve sample offsets with this instrument.

Edit Instrument

Step two.

Switch the sampling mode from DFD to sampler. Note that this will increase memory consumption of the instrument as well, so it's best to only do this when you really need it for an instrument.

Switch to sampling mode

Step three.

Go into the scripts editor and find the first empty script. In this script paste the following code:

on init
declare ui_knob $sampleStart (0,1000000,1)
set_text ($sampleStart, "S. Start")
set_control_par_str(get_ui_id($sampleStart),$CONTROL_PAR_AUTOMATION_NAME,"Sample offset")
end on
on ui_control ($sampleStart)
set_knob_label ($sampleStart, $sampleStart/10000)
end on
on note
ignore_event ($EVENT_ID)
end on

Don't forget to hit apply!

Insert script

Now offset should be available as an FX in REAPER which you can automate with Hackey Trackey.


Hackey-Trackey has a few options to allow for some customization in workflow. Pressing F11 opens the options dialog, where themes and keymappings can be chosen. Additionally, the following options can be checked or unchecked.

Auto Resize

Auto resize determines whether Hackey Trackey should resize whenever a new pattern is selected. The resizing in this case refers to the height of Hackey Trackey.

Follow Selection

When this is enabled, Hackey Trackey will always load the pattern currently selected in the sequencer. Note that this means that you cannot open multiple Hackey Trackey's anymore to look at different patterns simultaneously.

Info Sticks to Bottom

This makes the info at the bottom of the pattern remain fixed at the bottom, even when the pattern is shorter than the window. Alternatively, it will be at the end of the pattern.

Adjust Column Count to Window

This will automatically add columns to be visible whenever Hackey Trackey is resized.

Always Enable Recording

This will make Hackey Trackey always enable recording when opened. Note however that this changes the recording status of your project and is therefore disabled by default.

Follow Song

CTRL + F will toggle Hackey Trackey to follow the song position. It will attempt to find MIDI items at the current position on the current track and update the view so that you see them. Note that the status of this can be seen next to the [Rec] button.

CRT mode

Enable cheesy CRT effect. Works best with Hacker theme.

Special keys

These are just the default key bindings when you download the script. They are optimized for a QWERTY layout. If you wish to change the shortcuts, edit the keys table. If you wish to edit the note keyboard, edit the keys.pitches table. If you wish to know what keystroke particular key has, set printKeys to 1 and start typing. Note that control modifies keystroke values.

Key Action
Any key on the virtual keyboard Enter a note and advance
Shift + Key on the virtual keyboard Enter a note go to the next column
Arrow keys Navigate
Backspace Delete item and shift rows up
Del Delete item
Insert Shift all items down by one
- Place note OFF
ENTER Start play at cursor position
Space Start/Stop
CTRL + Z Undo
CTRL + B Start selection block
CTRL + E End selection block
SHIFT + Del Delete block
CTRL + I Interpolate block
CTRL + X Cut (To do)
CTRL + V Paste (To do)
CTRL + C Copy (To do)
CTRL + /\ Shift current octave up
CTRL + \/ Shift current octave down
SHIFT + CTRL + /\ Switch envelope mode (FX automation)
SHIFT + CTRL + \/ Switch envelope mode (FX automation)
Shift + Numpad + Shift selection up (e.g. C-1 -> C#1)
Shift + Numpad - Shift selection down
F1 Help
F2 Decrease output channel
F3 Increase output channel
F4 Decrease advance amount
F5 Increase advance amount
F8 Stop playing
F11 Options screen (theme etc)
F12 MIDI Panic (stop all notes)
CTRL + L Set loop to pattern bounds
CTRL + Q Set loop start before current row
CTRL + W Set loop end after current row
CTRL + ALT + Up Increase row resolution
CTRL + ALT + Down Decrease row resolution
CTRL + ALT + Enter Commit row resolution (WARNING: Destructive)
CTRL + -> Next MIDI item on track
CTRL + <- Previous MIDI item on track
CTRL + D Duplicate MIDI item
CTRL + N Rename MIDI Item
CTRL + R Arm (plays notes)
CTRL + +/- Enable/disable advanced options for this column
CTRL + Shift + +/- Add CC column (only possible when in advanced mode for CC programming
Harmony Helper keys
F9 Open harmony helper
CTRL + Click chord Insert chord at current position
ALT + Click chord Invert first note of chord
SHIFT + Click chord Invert second note of chord
Shift + CTRL + ALT + Numpad + Shift root note up (e.g. C-1 -> C#1)
Shift + CTRL + ALT + Numpad - Shift root note down

Feature requests

Feature requests are always welcome, preferably with an idea of how to achieve it with the Reaper API. If you've implemented a feature yourself and want it added to the trunk, submit a pull requests. If possible, try and make sure that the pull request is up to date with the latest version. I will do my best to review and incorporate these.

How does it work?

Hackey trackey maps already existing MIDI data to a tracked format and allows editing of such data in a tracker-based manner. If the MIDI data was entered via another method than Hackey Trackey, the default behaviour is to map the notes to non-overlapping channels. Once this is done, the channels for the MIDI data are remapped such that the column in which a note appears is stable from that point on. Note that if your instruments use the MIDI channel information for specific purposes then this plugin is not useful to you. Note that depending on what you are doing, the plugin may also add text events to your MIDI data to keep track of information Hackey Trackey needs to preserve the tracked layout.

The plugin uses the MIDI note channel property to store which column a note is in. OFF note termination symbols not associated with a normal note end and legato symbols are stored in text (OFF+channel and LEG respectively).

Because the plugin remaps the channel, non-tracker input should be created with channel 0. The plugin remaps data in channel 0 to MIDI channel 1-16, automatically assigning new incoming notes to a column where enough room is available. Notes in channel 1-16 are assigned first, to keep anything that was made in the tracker stable.

The location of the notes in the tracker view will be stable as long as no data is entered into MIDI channels other than zero via the piano roll or other methods.

Because typically, it is preferred to have MIDI data go to a specific out channel, the plugin optionally maps all the MIDI data to a specific channel via the out-channel property.


There are some things which are unfortunately not possible as far as I am aware. Voice stealing when placing overlapping tracked patterns is one of them. In Jeskola Buzz it was possible to play different patterns on the same row in the sequencer. This would cause notes that came from one pattern to stop notes coming from another pattern. This adaptive merging is not possible in this tracker since the different tracker instances are unaware of each-other's existence and overlapping MIDI elements act independently.

There is a second annoyance that comes with this, which is that for notes to be held over a pattern, they must be restarted at the start of the new pattern. The tracker has no way of seeing what notes may still be playing at the end of previous MIDI items. It may be possible to find a workaround for this in the future by scanning the timeline for previous MIDI items and adding such notes automatically.

Velocities can only be entered at a note start. Whereas in a tracker, every row can have its own velocity (modulation the notes velocity over time), it is not possible to assign multiple velocities to a single MIDI note. By default, when entering a velocity in a new line, the last MIDI note on that tracked channel will be copied to mimick the same end behaviour.

Note that when using the legato mode, it is no longer possible to have the same note be repeated on channel 1. Doing so would cause problems when playing the MIDI. Hence
1 D-2
1 D-2
would be merged into one single MIDI note. I have not found a good workaround for this so far, but if you have a good idea, please contact me.

Features to be investigated whether they are feasible/reasonable

  • Cutting/Copying to MIDI editor clipboard.
  • Adding HT to the MIDI menu via a configuration script.


A LUA tracker plugin for REAPER 5.x and up. Designed to mimick the pattern editor in Jeskola Buzz.





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