Sample Co. to Plugin Co.
Turning years of cult sample libraries into a drum plugin with real depth and no clutter
“Quote”
Stefan Runstrom
Drummer, owner Circles Audio
The Challenge: Depth Without the Clutter
Circles had built a, extensive catalog. Years of drum libraries recorded from dead vintage kits, 1980s drums, 90s rock, pop-punk, digital machines and dusty tape one-shots, quietly used on records far bigger than the company's profile suggested.
But it lived as sample packs, which meant it lived inside whatever sampler each customer happened to open. Finding the right snare meant hunting through folders. Building a kit from two libraries often meant running a second instance. And the things that make these recordings worth having, the room mics and the per-piece shaping and the routing, were either buried in a host Circles did not control or not available at all.
So the brief pulled two ways. Give producers real control over every kit piece, then make it land in an interface fast enough to use mid-take.
01 Discovery:
Mapping the Ecosystem
From wishlist to scope
We started by getting every idea out of their heads and onto paper, then worked that wishlist into a development scope: what to build first, what the architecture had to leave room for, what could wait.
Designing for expansion
Circles were not shipping one product, they were opening a shop. Every future library had to drop into the same plugin without a rebuild. That shaped the architecture before any engine code was written.
02 Development:
Alpha, Then Interface, Then Refinement
Alpha builds in their hands
The alpha ran as a series of builds Circles could load up and play, each one followed by feedback that fed straight back into the engine scope. Whether a choke group feels right, or a velocity response reads as musical, is not settled by a spec document. It is settled by a drummer sitting with the thing.
The engine
Multi-sampled playback across the full catalog, choke groups behaving the way drummers expect, and multi-mic material handled natively so the room mics from the original sessions stay available as a live blend. Every kit piece carries its own pitch, width, velocity, mic level, tone, transient, delay, reverb, drive, volume and pan, with a mixer on top for per-channel blend and output routing. The work was making that much per-voice processing run cleanly across a full kit.
The interface
Once the engine was signed off, we implemented the interface designed by Resonant Design with the Circles team, iterating until the browsing model held up in real use: kit presets, samples and MIDI beats all reachable from one view without losing your place. A further round of refinement followed.
Working around real lives
Circles are working musicians, so development ran in bursts with real gaps between them. The scope document did the heavy lifting here. Restarting meant carrying on rather than re-explaining.
03 Delivery:
A Product, Not Just a Plugin
Release and licensing
Final builds in VST3, AU and AAX for Pro Tools, Logic Pro, Ableton Live and other major DAWs, for MacOS and Windows, with Moonbase licensing integrated so Circles could sell and activate directly rather than handing the customer relationship to a marketplace.
Pack creator
We also built them a pack creator for converting their own content into plugin packs, so new and rebuilt libraries ship on their schedule rather than ours.
Launched on their terms
The plugin was finished and handed over well ahead of the June 2026 launch, which gave Circles time to wrangle the catalog content and build the storefront around it. It launched with four libraries already inside - Dead Digital, Dead Vol 3, Digi and Dead HiFi - and expansions available from day one.
Outcome: Their Catalog, Their Product
The Circles Plugin gave the company its own product and a direct relationship with the people who buy from them. The catalog that used to be a folder of downloads is now an instrument, and every new library extends it rather than sitting beside it.
What we delivered
- Scoping & Specification
Turned the client's full wishlist into a development scope defining what to build first and what to leave room for.
- Alpha Programme
A series of playable builds for the client to test and feed back on, refining the engine scope before sign-off.
- Sampler & DSP Engine
Multi-sampled playback engine built from scratch, including multi-mic handling and choke groups.
- Per-Piece Sound Design Tools
Independent pitch, width, velocity, mic level, tone, transient, delay, reverb and drive controls for every kit piece.
- Mixer & Routing
Per-channel volume, mic blend, pan and multi-output routing so kit pieces can be sent to external plugins.
- UI Implementation
Implemented the interface designed by Resonant Design and Circles, iterating until the workflow held up in real sessions.
- Licensing Integration
Moonbase licensing for secure activation of the plugin and its expansions.
- Pack Creator
A content conversion tool letting Circles build their own packs and ship libraries independently.
- Cross-Platform Builds
VST3, AU and AAX for both Windows and macOS.