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16 Track Live Step and Morph Sequencer + advanced Arpeggiator

Created 2003-2007

NOTE: This design is expired! In 2009 MIDIbox SEQ V4 has been developed which replaced the old version. See this page for more details.

Feature list of MIDIbox SEQ V3:

  • optimized for live playing and editing
  • intuitive user interface with flat menu hierarchy, wide screen display (2 * 2x40 = 160 characters) and 16+1 rotary encoders with menu page dependent "soft function".
  • up to 5 MIDI Out ports for reduced MIDI latency
  • up to 2 MIDI In ports (e.g. for separated MIDI clock and MIDI keyboard input)
  • every parameter can be modified in realtime w/o affecting the sequencer timings
  • one sequencer pattern consists of 4 independent tracks
  • four patterns can be played at the same time -> makes 16 tracks
  • each track consists of 3 layers which can be assigned to various parameters (e.g. Note/Velcity/Gatelength, Chord/Velocity/Gatelength, 3 Notes, 1 Note + 2 CCs, 3 CCs, ...)
  • Transpose and Arpeggiator function
  • Force-to-Scale function with 128 predefined scales
  • Chord Memory function
  • Track directions: Forward/Backward/PingPong/Pendulum/Random Dir/Random Step
  • Track direction progressive parameters (Step Forward, Jump Back, Repeat)
  • free adjustable clock divider for each track. Supported timebases 1..64, normal and tripled
  • available length for every track: 1-32 steps
  • up to 4 tracks can be chained to extend the number of steps
  • with 96ppqn resolution, 64th notes can be played
  • loop point within track
  • step events can be triggered multiple times (up to 4 times per step) with a delay value of 1-31 to realize drumrolls, ratterbeats, flams...
  • 3 trigger layers for Gate/Skip/Accent/Glide/Roll/Random Gate/Random Value
  • various Groove styles (shuffle/inverted shuffle/...), prepared for 16 styles
  • Humanizer function (random modification of note/velocity/gatelength)
  • Pattern Morphing, controllable in 128 steps with a Modulation Wheel
  • Manual step triggering
  • Step and Realtime Record function
  • Copy/Paste/Clear function
  • Scroll and Step Move function
  • Random pattern generator
  • Undo function
  • parameters of multiple steps can be changed relatively and absolutely with a single rotary encoder
  • parameters of multiple tracks can be changed the same time with a single rotary encoder
  • Tracks can be muted
  • Accent/Slide/CC sequences
  • inbuilt MIDI mixer/controller with 128 free definable mixer maps
  • inbuilt MIDI router
  • virtual "Loopback port" for Master/Slave tracks
  • split function for Transposer/Arpeggiator
  • 8 optional CV outputs and gates for analog gear
  • CV outputs can also be accessed from MIDI In (-> replaces a CV interface)
  • 48 optional 1 mS drum trigger outputs
  • 128 patterns can be saved in every 64k BankStick
  • additional BankStick for up to 16 songs with 16 parts, each consists of 8 pattern sets
  • additional BankStick for up to 128 mixer maps
  • pattern sets can be looped and chained in song mode
  • phrase mode which allows to switch between the 16 predefined pattern sets (for fills/breaks/chorus, etc...)
  • pattern switching can be synchronized to the measure
  • MIDI Remote functions
  • 48-255 BPM (MIDI clock master)
  • external sync (MIDI clock slave)
  • DIN sync output for controlling vintage sequencers
  • works with quadrubled MIDI clock resolution (96 ppqn)
  • several hardware options (e.g. a 64 Button/Duo-LED matrix)
  • details and demo samples in the User Manual
  • DIY ONLY!!! (commercial release neither planned, nor allowed!)


MBSEQ V3 is the third generation of the MIDIbox sequencer project.

It started as a primitive extension of MIDIbox 64, which allowed to play four tracks controlled from 64 analog pots. Highlight was the arpeggiator mode with an uncommon definition of an "Arp Event", which is still one of the main features of MIDIbox SEQ today.

With MIDIbox SEQ V2 the project advanced as a separate application, based on MIOS and the PIC18F452 microcontroller, enhanced by a new user interface with two 2x40 LCDs and rotary encoders instead of pots. During the development I had to fight against a lot of limitations of the PIC18F452, accordingly the feature set was limited, incomplete, not always fully functional.

MIDIbox SEQ V3 is the reincarnation of the project, based on the bigger PIC18F4620 microcontroller which is hardware compatible to the PIC18F452. This chip contains more code memory (64k instead of 32k) and more RAM (3986 instead of 1536 bytes). Accordingly it allowed me to implement the MIDIbox SEQ application almost free from hardware restrictions, and to enhance it by features I was not able to realize in previous versions.

During the last years I got a lot of inspirations and feature requests from MIDIbox users, which went into the firmware. Although I wasn't able to realize all recommendations, e.g. due to the resulting implementation effort (I'm a sparetime programmer!) or conceptional mismatches (it's really difficult to fully understand and combine everbody's wishes), I want to explicitly mention, that MIDIbox SEQ V3 wouldn't be where it is today without your input! Thank you! :-)

Basic Usage Concept

Each track consists of 3 parameter layers. In the simple case, a layer controls Note, Velocity and Gatelength. But there are also other combinations selectable like:

  • Chord (up to 4 notes), Velocity, Gatelength
  • 3 Notes (Velocity and Gatelength fixed)
  • 3 Velocities (Notelength and Gatelength fixed - for Drums)
  • Note, Gatelength and additional CC (to control an additional sound parameter)
  • Note and two CCs (to control two additional sound parameters)
  • 2 CCs und Gatelength (e.g. for Trancegate effect)
  • 3 CCs (e.g. for envelope modulation)
  • etc. (all modes are described in the User Manual)

The layer which is displayed on the LCDs, and which can be modified with the rotary encoders, can be selected with the layer buttons

Trigger functions like Gate/Skip/Accent/Glide/Roll/Random are also accessible in 3 "trigger layers"

Notes can be played as "Arpeggio". "Arp Events" are realized in a special way which might sound unusual, but which is very powerful: up to 4 notes can be played on a keyboard. Each step can pick up one of this played note, and transpose it.

There are functions available to randomize the played notes/CCs

A track consists of 32 steps with a resolution of 64th note to 1 quarter note, triggerable with a resolution rate of 96 ppqn. Steps can be looped, and the progression can be controlled with an algorithm which consists of a "Step Forward", "Jump Back" and "Repeat" parameter.

A pattern consists of 4 tracks, the tracks can be optionally chained to enhance the track length to 128 steps. This makes especially sense for 32th and 64th notes, but also for melody lines.

Next to this pattern, you can create a second one which contains a variation. With the modulation Wheel it is possible to morph between these two patterns with a resolution of 128 steps

4 patterns can be played concurrently (small side calculation: since each track can play up to 4 events, and a pattern consists of 4 tracks, up to 64 MIDI events can be played in parallel!)

The 4 patterns can be combined to pattern sets, which can be triggered with a single button to build up a song parts interactively ("Phrase Mode").

Additionally, pattern sets can be chained and looped in Song mode.

  • Patternset 1 plays "A1 C1 E1 G1" permanently
  • Patternset 2 plays (3 * A2 C1 E1 G2) and (1 * A3 C1 E1 G3)
  • Patternset 3 loops between (A4 C4 E4 G4) und (A5 C5 E5 G5)

Switching between the pattern sets works immediately, or synchronized to the measure

With the mixer maps it's possible to prepare sound setups for your synths (independent on the MIDI port to which they are connected), and to control sound parameters while patterns are playing.

The MIDI router allows to forward MIDI events from the MIDI In port to the MIDI Out port of your synths, so that you don't need to re-connect the MIDI cables if the synths should be played from another source (e.g. from another MIDI sequencer or from a MIDI keyboard).

Tracks can be muted and solo'ed to build up a phrase. But the most important: everything is editable in realtime, the sequencer will response immediately and it is possible to optimize sequences w/o jostling the computer mouse over the table - this is the big difference compared to Mac/PC based sequencers!

Sneak Previews

During the development phase of MIDIbox SEQ V3 I created some videos to demonstrate the new possibilities to the community. I think that they give a nice impression about what you can expect from the project, but please note: my musical skills are limited! I'm more a slave of my algorithms than an artist! ;-)

YouTube Live session with MIDIbox SEQ V3 (the stereo MP3 version is here):
YouTube And another session with MIDIbox SEQ V3 (the stereo MP3 version is here):
YouTube Demo of the new Button/Duo-LED switch matrix, supported by MIDIbox SEQ V3 (the stereo MP3 version is here):

More demo samples are available in the User Manual.

Wishlist for future releases

  • currently no item - old TODO list has been completely implemented in release V3.2! :-)


Schematics & PCBs
File Size Description
MBHP LINK see MIDIbox Hardware Platform
mbseq_v3_interconnections.pdf 14k Module Interconnections
mbseq_v3_din.pdf 26k default DIN pin assignments for the setup_mbseq_v3 option
mbseq_v3_dout.pdf 11k default DOUT pin assignments for the setup_mbseq_v3 option
Pictures LINK Some pictures of the inner life of MIDIbox SEQ
Pictures LINK Some pictures of the optional 64 Button/Duo-LED extension
mbseq_v3.fpd 3k Panel which can be edited with the Frontpanel Designer of Schaeffer Apparatebau
MIOS Download LINK The PIC18F4620 firmware
Options LINK Description about various hardware options
Manual LINK User Manual
mbseqv3_remote_functions.txt 2k MIDI Remote functions of MIDIbox SEQ V3
mbseqv3_remote_functions.pdf 2k Graphical overview about the MIDI Remote functions of MIDIbox SEQ V3
mbseqv3_cc_implementation.txt 12k CC Implementation of MIDIbox SEQ V3
mbseqv3_sysex_implementation.txt 1k SysEx Implementation of MIDIbox SEQ V3
mbseq_preset_list.pdf 22k Matteo Bosi has created a useful sheet template where you can write down some notes about the saved tracks - it improves the overview a lot!
MIDIbox Forum LINK Support at the MIDIbox Forum
MIDIbox Wiki LINK A lot of additional informations on MIDIbox and MIOS

NOTE: This design is expired! In 2009 MIDIbox SEQ V4 has been developed which replaced the old version. See this page for more details.

Last update: 2023-11-04

Copyright 1998-2023, Thorsten Klose. All rights reserved.