Frequently Asked Questions

The idea started years ago after discovering how rewarding it was to get both drum and melodic sounds out of an e-drum kit. For several years Bill worked hard on a way to do this using the configurations and programmability of various synths and drum machines, leading later to Max and Max for Live — which worked, but led to a sprawling Ableton template with loads of interconnected M4L objects, both off the shelf and custom-built. Old Live sets that performed well became fragile over time as objects aged out and grew hard to update.

After years of spending more time debugging and troubleshooting than actually playing, it became clear something had to change. With a decade of experiments and requirements accumulated in various objects, on paper, and in memory, a rewrite in C++ went quickly — the first proof of concept worked better than all the prior effort combined.

DrumStrum doesn't try to do everything, and there's much it deliberately leaves on the table for your own creative exploration. It doesn't make sounds of its own, doesn't do algorithmic sequencing, doesn't compete with chord entry devices, and its MIDI looper is intentionally minimal and fun rather than deep. It doesn't do much music theory — chord expand and some of the bass modes are about as far as it goes. What it does do is strum whatever chord you send it and handle the plumbing required of a complex, constantly-evolving electronic drum kit or multi-controller setup. If you want to do complex and unique MIDI transformations beyond what DrumStrum offers, go for it — some of what DrumStrum outputs, like root note detection, is specifically designed to drive third-party M4L devices downstream.

The goal of DrumStrum is simple: spend more time playing, less time futzing with your drums.

DrumStrum is a MIDI processor that lets your drum pads play chord tones in real time. You define the current chord on a keyboard or any MIDI source, and DrumStrum maps your pad hits to notes from that chord. Hit a pad — get the root. Hit another — get the third. The rhythm comes from you; the harmony comes from the chord.

It runs as a menu bar app on Mac and Windows, sitting between your controllers and your DAW. No audio — purely MIDI. It creates its own virtual port called DrumStrum that any MIDI software can connect to.

Everything flows out through that one virtual port, but DrumStrum can populate many MIDI channels simultaneously — each carrying a different type of content. Mixed with suitable sounds, your playing is conducting an entire ensemble, orchestra, or soundscape:

Channel numbers above are examples — all assignments are configurable.

No. DrumStrum works with any standard USB MIDI controller and creates its own virtual MIDI port automatically — no IAC Driver setup, no extra software. Just plug in your controllers, point your DAW at the DrumStrum port, and you're ready.

Yes — DrumStrum runs on Windows 10 and later. Windows requires a free virtual MIDI port utility (such as loopMIDI) to create the virtual port DrumStrum uses for output. See the Requirements section of the manual for details.

They're coming — but it's a work in progress. Bill's first pass at explaining DrumStrum ran to four hours. Nobody, including Bill, wants to watch all of that. Especially when it's more fun to just pick up some sticks and play.

In the meantime, the best approach is to dig in: explore the app, use this FAQ and the User Manual, and try things out. DrumStrum is designed to be discoverable, and most concepts click quickly once you're playing.

If you get stuck or have questions, come find us on the Discord server or email Bill directly — we're happy to help.

DrumStrum actually started as an Arduino project, and the core C++ strumming engine was designed from the ground up to be platform-agnostic. It's fully compatible with Arduino, Raspberry Pi, Daisy, and similar embedded platforms — so a standalone hardware version is very much a possibility.

Hardware development took a back seat while we focused on getting the Mac and Windows app finished, but there are definite aspirations for a dedicated hardware unit, including a Eurorack module. If you're interested in pursuing a DAWless or embedded implementation, get in touch — licensing the C++ engine is also on the table.

Yes. DrumStrum is free to download and use with no time limit. The core features — Transformers, Routing, Maps, Dashboard, Trace — are free forever. Premium features (Presets and Looper) require a license.

DrumStrum creates a virtual MIDI port named DrumStrum automatically when it launches. In your DAW, create a MIDI track and set its input to the DrumStrum port. That's it — no IAC Driver or other virtual MIDI software needed.

If the port doesn't appear in your DAW, try clicking Refresh MIDI in DrumStrum's Routing tab, then check your DAW's MIDI preferences again.

• Open the Trace tab and hit a pad. If you see incoming MIDI messages, DrumStrum is receiving the signal — the issue is in transformer configuration.
• Check that the Transformer's MIDI In channel matches what your controller sends. Most drum controllers default to channel 10.
• Make sure the correct input device is selected on the transformer card.
• Verify the transformer is enabled — there's a small toggle pill in the top-right of each transformer card header.

Go to the Routing tab and click Refresh MIDI. This cycles DrumStrum's virtual port and re-opens all physical MIDI connections, which also prompts your DAW to reconnect. Most controller resets and patch switches are fixed instantly by this.

Click the menu bar icon and choose Panic, or go to the Routing tab and click the Panic button. This sends All Notes Off (CC 123) on all MIDI channels.

You can also assign a Panic action to any pad in your Transformer settings for quick access while playing.

Yes — route DrumStrum's output directly to a hardware synth via USB or a MIDI interface. Select the synth as the output device on your transformer card. No DAW required.

Absolutely — and this is one of the core reasons DrumStrum exists. Hybrid e-drum setups often involve several controllers at once: a pad controller for strumming, a separate bass trigger, a keyboard for chords, maybe an additional surface for looper controls. A big part of what DrumStrum does is provide the MIDI plumbing to make all of that work together cleanly.

Each controller gets its own Transformer with its own input device, MIDI channel, pad assignments, and output routing. They all run simultaneously and independently. And if your setup changes gig to gig, it's easy to deactivate individual controllers without deleting them, or save entire configurations as named Presets to switch between setups instantly.

No — DrumStrum opens all available MIDI inputs directly, so your controllers can connect to it without touching your DAW at all. Direct connection is often the better choice: it removes the DAW from the MIDI path entirely, which can meaningfully reduce latency. For drummers especially, that difference is noticeable.

The one reason to route through your DAW first is if you need to pre-process the MIDI before it reaches DrumStrum — for example, filtering or transforming notes through a Max for Live device. If you don't need that, skip the DAW in the signal path and connect directly.

First, decide where your sustain messages are coming from. Common sources include the foot pedal input on your keyboard, a dedicated footswitch controller (such as a Dore or MIDISolutions unit), or even a drum pad assigned to toggle CC 64 on and off. DrumStrum can handle all of these simultaneously.

For each source, add a CC Router transformer and define a rule specifying the input CC number (CC 64 for standard sustain), the output CC number, and which MIDI channels to send it to. A single incoming CC can fan out to multiple channels at once — and different pedals can be routed to different channels independently, which opens up some very custom possibilities: sustain on your strum channel only, expression on your bass channel, a pad toggling hold on a specific synth, and so on.

If you just need a pedal to pass through unchanged without any routing logic, you can also enable CC Passthrough on a Strummer transformer as a simpler alternative.

DrumStrum ships with built-in maps for Roland V-Drums, GM Drums, Ableton Core Drumrack, a standard MIDI keyboard layout, and MuseKinetics BopPad. If your kit isn't on that list — Alesis, Yamaha DTX, Nord Drum, Roland SPD, and many others — it takes just a few minutes to create your own. It's a one-time setup and the map is reusable forever.

Go to the Maps tab, create a new map, and add a row for each pad. Use MIDI Learn to capture the note number automatically — just click Learn and hit the pad. Then give it a label that makes sense to you: "Kick", "HH Edge", "Cymbal Bell", whatever. Once the map is saved, select it as the input map on any Strummer or Note Remap transformer and assign actions to each pad from there.

Output maps work the same way but describe a destination rather than a source. If you're targeting a device like the Eventide Misha or any module with note-triggered actions, create an output map with labels for each action — then your transformer cards show friendly names instead of raw note numbers.

See the Controller Notes section of the manual for a full walkthrough.

It depends on the Latch Mode setting in the Chord Entry card:

• Always On: DrumStrum captures the chord the moment you play it and holds it until you play something new. You don't need to keep holding the keys. This is the most common mode for drumming — it frees both hands.
• Momentary (CC): The chord is held only while a assigned CC footpedal is pressed. Release the pedal and the chord clears. Useful when you want precise control over exactly when the chord is active.
• Toggle (CC): A CC footpedal toggles the latch on and off. Press once to lock the chord in; press again to release it. A good middle ground between Always On and Momentary — hands-free hold without committing to a permanent latch.

There are several categories:

• Chord Note 1–7: Plays the Nth note of the chord sorted low to high. Wraps if the chord has fewer notes than the position selected.
• Play All: Fires all chord notes simultaneously — a full chord stab.
• Upstroke / Downstroke All: Fires all chord notes in rapid succession low→high or high→low, with a configurable strum delay between each note.
• Iterator Up / Down: Advances a shared position counter through the chord on each hit, wrapping at either end. Multiple pads assigned to iterators share the same counter.
• Random: Plays a pseudo-random chord note, guaranteed different from the last hit.
• Velocity Strum: Maps hit velocity to chord position — hard hit plays the lowest note, soft hit plays a higher one.
• Bass actions: Root, Root/Fifth, walking bass, pedal, and more — see the Bass Actions reference.
• Looper actions (premium): Record Toggle, Stop, Clear, Undo, Transpose Toggle, Frippertronics Toggle.
• Pass Through: Forwards the raw note unchanged, bypassing chord processing.
• Panic: Sends All Notes Off (CC 123) on all MIDI channels — instant silence if notes get stuck.

Chord Expand lets DrumStrum build a full chord from a single incoming note. Instead of playing a complete chord voicing on your keyboard, you play just one note — and DrumStrum constructs the harmony around it automatically. This is especially useful for drummers, who rarely have a free hand for keyboard playing. You can feed that single note from a drum pad, step through a sequence of notes using an iterator action, use a mallet controller with one stick, or tap a key on your keyboard with a finger while still holding your sticks.

A configurable CC — assignable to a mod wheel, expression pedal, MIDI pad, or any CC source — then lets you cycle through different chord flavors built on that note: major, minor, dominant 7th, suspended, and more. This gives you real-time control over the harmonic quality of the chord while you play.

There's also an option to replay the chord immediately when the CC changes. Because switching chord quality is usually a musically significant moment, this ensures the new voicing is heard right away rather than waiting for the next pad hit.

Root Detection analyzes the incoming chord using interval analysis and sends the identified root note on a dedicated MIDI channel — useful for driving a bass synth automatically without having to explicitly set a bass note every time the harmony changes.

It can also output the root as a CC value (pitch class 0–11) on a configurable channel and CC number, for driving CC-mapped parameters in your DAW or modular gear.

Setting a pad action to Passthrough forwards the raw MIDI note from your controller to the output unchanged. The note isn't transformed through the chord — whatever your pad sends is what comes out. Useful for pads you want to use as standard drum hits alongside your chord-triggered pads.

You're in luck — Bill has three of them, because they're cheap, light, and super responsive. One of the things Bill built specifically for the BopPad is a way to split its four physical zones into up to 12 logical zones. That makes finger or stick drumming on a BopPad a lot more fun and capable, giving you far more expressive real estate from a single pad.

There is a simple configuration you need your BopPad to have for the 12-zone decoding to work. Email Bill about this — he hasn't gotten around to documenting it yet.

Yes. Each transformer card has a small toggle pill in the header. Click it to disable the transformer — it dims and DrumStrum stops processing it. Click again to re-enable. The disabled state is saved with your configuration, so disabled transformers stay off across sessions. This is useful for debugging complex multi-transformer setups.

A CC Router transformer routes CC messages from one channel to one or more output channels, with optional CC number remapping. Common uses:

• Routing a sustain pedal to multiple synth channels simultaneously
• Remapping an expression pedal CC to a different CC number expected by a specific synth
• Sending one incoming CC to multiple output channels at once
• Toggle mode: converting a momentary CC (0/127) into an alternating on/off toggle
• Repurposing a sustain pedal, mod wheel, or expression pedal to a different CC number — either for use inside DrumStrum (such as chord expansion, chord latch toggle, or sustain routing) or outside in your DAW (such as automating a VST filter cutoff, triggering clip launch, or driving any automatable parameter)

The CC Router respects the input device assigned to the transformer card. Channel filtering is per-rule — set In Channel to 0 on a rule to match that CC on any channel from the assigned device.

There's also a special case called CC Strum: a dedicated transformer type that triggers a strum through the current chord when a CC crosses a threshold. This lets you strum via a mod wheel, expression pedal, or any continuous controller — push the wheel and DrumStrum fires the chord notes in sequence, just like a pad hit would.

That depends on the Loop Mode setting:

• Output: Records the transformed MIDI notes that DrumStrum sends out.
• Input: Records chord changes so the loop replays harmonic movement even when you stop playing the keyboard.
• Both: Records output notes and chord changes simultaneously.

Frippertronics is a looping technique popularized by guitarist Robert Fripp, where recorded material fades gradually with each pass while you continue overdubbing. In DrumStrum, the Frippertronics Decay setting (1–99) controls what percentage of velocity is subtracted from each note on every loop pass. Higher values fade faster. Set to 0 for a standard loop with no decay.

The result is an evolving ambient texture where older material fades into the background as new material takes over — without ever explicitly stopping and re-recording.

Looper actions (Record Toggle, Stop, Clear, Undo, Transpose Toggle, Frippertronics Toggle) can be assigned as the primary action on a dedicated pad. You can also use the double-tap trigger: define a note and a looper action in the Looper tab's trigger list, and two quick hits on that note will fire the looper action without affecting its normal single-hit behavior.

Presets, the Looper, and some walking bass modes require a license. All other features — Transformers, Routing, Maps, Dashboard, Trace, and the core bass actions — are free with no time limit.

A single license can be installed on up to 5 machines. If you need to move a license to a new machine, you can deregister an existing one to free up a slot — no need to buy again.

Click Activate License… from any locked feature or from the menu bar icon. The Buy a License button in the activation dialog takes you to a secure checkout. After purchase you'll receive a license key by email.

Check your spam folder first — license emails sometimes end up there. If it's not there after a few minutes, email us at drumstrum.support@gmail.com with your purchase confirmation and we'll get it sorted.

Yes — a DrumStrum license supports up to 5 machines. To free up a slot, use Deactivate This Machine… from the menu bar icon, then reactivate on the new machine with the same key.

Yes. If DrumStrum doesn't work for you, email us within 30 days of purchase and we'll issue a full refund, no questions asked.

DrumStrum checks for updates automatically once per day. When an update is available, you'll see a notification and can install it with one click — no need to visit the website.

To check immediately: click the menu bar icon and choose Check for Updates…

No. DrumStrum maintains backwards compatibility with saved configurations across updates — your setup will load correctly after any update. In the rare case that a significant change affects saved configs, it will be documented clearly in the Changelog.

Yes — this is on the roadmap. Several DrumStrum settings can already be controlled via CC in real time, and that surface is a natural fit for a Max for Live UI that speaks to DrumStrum while you play: switching transformer states, changing chord map selections, toggling strum direction, and more — all automatable from a patch living inside Ableton.

The goal is a clean M4L device that exposes those controls as knobs and buttons, tightening the feedback loop between what DrumStrum is doing and what Ableton sees. This kind of real-time, performance-driven control is central to the dynamism DrumStrum is built around. We'll share more as it comes together.