Endorphin.es Ground Control is a 42hp sequencer designed to be the main brain [and even power!] for a Eurorack system. It features three melodic tracks with CV/pitch and gate outs, and a drum track with 8 trigger outs. All track outputs are along the top of the module. There is a mute/solo bus with individual mute/solo buttons for each lane in the drum track and one for each melodic track’s CV/gate pair. There are ins and outs for MIDI [TRS type B], global reset, and clock, as well as individual reset and external CV modulation inputs for each track. Below the mute bus and moving from left to right are two sets of buttons for changing patterns, adjusting various parameter values, and transposition of track steps. There is a four-character, seven-segment LCD screen with associated track selection buttons along with two rows of buttons that constitute the transport controls, track subdivision selection, and a host of shift functionality.
Ground Control also has USB ports for device [USB type B] and host [USB type A] as well as a DC barrel jack and in an inspired move, the module can be used to supply power [with an external 12-20V DC power adapter] through a connected passive or flying bus-board [up to 1A on the 12V rail, 700mA on the -12V side and will even provide +5V if needed], conceivably eliminating the need for a powered case for a small system. Nice!
Ground Control has a two-octave silicone keyboard and these keys also double as quick access to the Ground Control's various shift functions, settings, and pattern selection. The keyboard itself is not velocity or pressure sensitive, although these parameters can be recorded via an external MIDI controller or adjusted internally [although aside from the single modulation out, velocity messages will only be sent out via MIDI—both the TRS out and via USB]. The keys/buttons on the Ground Control are a bit stiffer than they look but I quickly got used to them, and since they aren't used for any kind of performative nuance it doesn't really matter much.
The module has a few hard-coded scale settings: Chromatic, Major, Minor, Harmonic Minor, Lydian, Major Pentatonic, and a Custom user scale and four inputs for external CV that feed into a flexible modulation matrix. Modulation parameters include Pattern Shift, which will nudge the pattern forward or backward depending on the voltage present over the 64-step range, both a semi-tone and octave offset over +/- 5 octaves, the Shuffle amount, Probability percentage, and number of Ratchets, Slide time, Gate length, and both a unipolar and bipolar CC value for sending modulation to connected MIDI gear. Inputs can be freely assigned to any of the modulatable parameters with the caveat that only one input can be assigned to a parameter per track. In other words, CV input 1 could be assigned to Pattern Shift for track 1 but you cannot then assign CV input 2 to also modulate Pattern Shift on the same track [Pattern Shift would only be available for the other 3 tracks]. Having four external modulation inputs is excellent and, despite not being able to stack modulation, makes for a great deal of flexibility and creative options.
There are a few options for creating or recording patterns into its tracks, and the available methods are step sequencing, live recording, and x0x-style step editing for the drum track. All tracks have an arbitrary length with a maximum of 64-steps per pattern and each track can have a total of twenty-four patterns. All tracks and patterns are stored within a project and the Ground Control can store up to twenty-four projects at a time. Patterns can be played back in a number of different ways including forward, reverse, pendulum [forward then backward], random, and random step, which flips a coin at each step to decide if the sequence moves forward or backward.
Step recording is the most straightforward and pretty intuitive on the module. The pattern length is set dynamically based on the number of notes/rests played [up to a total of 64 steps] and makes creating polyrhythmic variations a breeze. Slides between notes can be played in during step recording by overlapping the pressing of two individual notes, and is a really nice feature that can add some interest to your melodies and grooves. In lieu of having velocity sensitive pads, the ability to add glides in an intuitive way is great. Rests and Ties can be entered by using the Tempo button for rests or the Tie [quarter note] button plus a note key for ties [holding the Tie button and pressing a note for as many steps as you'd like to tie for]. Once you’re done with one track you can hot swap to another and continue to enter steps on the new track without having to exit out of the step record mode. It’s a small time saver but it shows how much thought Endorphin.es has put into optimizing the Ground Control for efficient creative expression.
Step recording on the drum track is similar, but utilizes the black keys labeled 1-8, with each key corresponding to one of the eight drum track trigger outputs. In combination with the Rest button, you can "play" each track and build up a drum sequence that way. Each track has its own sequence so you need to enter each drum track's notes separately, meaning you can't "play" a bass, snare, and hi-hat pattern at once in this mode, you would have to "play" each part individually along with needed rests. This can be pretty awkward, but luckily for programming drums, the Ground Control has an x0x-style mode for drums and this is the best method for laying down patterns [or with the most control]. Long-pressing Record and selecting track D allows you to enter triggers on a 16-step grid [patterns can be up to 64 steps long but are shown in pages of 16 steps]. Because it shares the keyboard layout, the trigger grid is a bit funkily laid out and uses F# and D# as steps 2 and 15 respectively. This little quirk is noted nicely on the newer silver panel design by outlining every fourth step in black. The other black keys [labeled 1-8] are for selecting which drum you want to edit.
By pressing Record while the sequencer is playing you enter live recording mode, which allows you to record your performance on one of the melodic tracks, or the drum track in real time. The notes are quantized to that particular track's subdivision setting [and you can have different subdivisions set per track] but there is no option [currently] to record notes live in an unquantized state. This is something to keep in mind if you like to add a little off-grid wonkiness to your sequences or just prefer not to have everything locked in time. Additionally, the sequencer can be set to "wait to record" and in this mode it will wait to start the live recording until the first note on the keyboard is pressed. The wait to record mode is great for experimenting on the fly with different melodies or arpeggios while still ensuring that you can always sync up with the first note of the sequence.
Individual steps and their note or rest data, ties, slide, and ratcheting can be adjusted in the Editor mode and Ground Control offers both a static editor [while the sequencer is stopped] and a Live edit mode. You can page through the different steps and edit the note value as well as the different note features—Tie, Rest, Ratchet, and Slide [which are all on/off only]—or "flags" as Endorphin.es calls them. Notes and triggers can be edited in Live edit mode as well, although it can be a bit tricky to see where all of the melodic notes are, especially in a longer pattern. Drums are pretty straightforward to edit live as each pattern is laid out in pages of 16 steps.
The Ground Control doesn't have a song or arranger mode, but as an alternative offers pattern chaining as a way to automate the switching of patterns. Chaining is super easy and only consists of holding the track you'd like to create a chain for and then pressing the corresponding pattern letters in the keyboard [A - Z]. Up to twenty-four patterns can be chained together and chains can be saved with a project. It is important to note that the chains are dynamic and so without saving them, any new chain will overwrite the previous [unless saved]. Pattern chaining is really fun and with a bit of planning you can build up quite complicated arrangements.
Another standout performance feature of the Ground Control is its arpeggiators. Each of the melodic tracks can operate in arpeggio mode. The arpeggiation patterns are pretty standard: Up, Down, Random, and Order [notes played in the order that they are pressed] and will follow the subdivision that is active for that track. The keyboard can be latched so that you can release the keyboard and the arp will continue; and it can also be "super latched," wherein you can add notes to the arpeggiated pattern one at a time [up to a total of twenty-four] and they will continue to play. Notes that are already in the sequence will be removed if pressed again. Latched patterns can be transposed and are also subject to the probability/"humanization" settings of the track. Playing arpeggios can also be recorded into a track in real time, so if you have something you like it’s easy to get it into the sequencer. When on the Drum track, the arpeggiator acts as a fill button or drum roller so that pressing a drum track key will trigger it repeatedly. In Roller mode the track subdivision can be changed on the fly but will only record into a sequence at the initial subdivision chosen for the track. Additionally, all tracks can have the arpeggiator latched and playing at the same time.
In the Eurorack landscape there are a lot of sequencers to choose from and finding the one that fits best can be a challenge. Ground Control aims to be a jack-of-all-trades modular brain, and with a few caveats, makes a strong case for it. It lends itself well to producing beat-driven and grooving music, and while it does work to create looser, more generative sequences, it really thrives in a more dance music oriented space. As the flagship sequencer for Endorphin.es, this focus makes perfect sense and the Ground Control would pair perfectly with Endorphin.es' drum synth modules Queen of Pentacles or Black Noir. Acting [if desired] as the power supply for a small system is a brilliant stroke and adds greatly to the Ground Control's one-stop-shop impression.
I do think there are a few things that could really push Ground Control to another level, though. Being able to sequence MIDI tracks polyphonically instead of simply playing polyphonically via MIDI would be great, and an additional MIDI mode that would allow for four simultaneous MIDI tracks to go along with the drum track and 3 monophonic melodic tracks would be stellar. From a performance standpoint, having the option to record a sequence that is not automatically quantized to the track subdivision would offer up a way to add a little human-generated humanization to things as well. Lastly, it would be nice if the probability and ratchet amount weren’t only a global per track setting. Given the Ground Control’s stellar jam-ability and inspiring interface it’s a limitation which is a little disappointing as the ability to adjust the probability and ratcheting amounts on a per-step basis would push the creative potential of the sequencer even further. These are small nitpicks, however, and Endorphin.es has made some conscious choices to focus on a feature set that prioritizes live performance and nimble, intuitive adjustments. While it’s true that there are some "deeper" features that could have been implemented [and still may yet happen, as the manual hints at future updates] the streamlined user experience is relatively easy to wrap your head around—which is saying something when it comes to a complex Eurorack sequencer module—and the limitations are ones that tend to help one avoid the pitfalls of endless tweaking and overthinking things. I love how easy it is to get an idea going and then seamlessly expand upon that idea, and the Ground Control never seems to get in the way of a good idea or flow. While those looking for an ambient generative music making partner may want to look elsewhere, the Ground Control is an awesome module for jamming and is perfect for a late night of beat-driven music making.

42 HP +12v 420mA -12v 0mA
Price: $719

Endorphin.es