Here is the critical truth that separates amateurs from professionals. If you download the Eric Prydz Opus MIDI, drop it on a basic piano, and hit play, you will be bored. It will sound like a cheesy ballad.
Why? Because Opus is a record about automation, not just notes. eric prydz opus midi
Eric Prydz uses the MIDI as a static anchor while everything else moves. To recreate the feeling of Opus, you must use the MIDI file as a launchpad for motion: Eric Prydz — "OPUS" (MIDI Report) 7
The Core Hook: The MIDI consists of a repeating 8-bar chord progression. The theoretical foundation is straightforward: Set tempo to 126 BPM, key to F minor
The "Boredom" Factor: If you open the MIDI in a piano roll, you will see the same block of notes repeating for nearly 9 minutes. To an untrained eye, it looks like a lazy loop. To a producer, it represents restraint. The MIDI provides the skeleton; the song relies entirely on the "meat" (synthesis and filters) to create the journey.
The Breakdown Arpeggio: During the breakdown, the MIDI shifts from block chords to a rolling, rhythmic pattern (often grouped in 3s against the 4/4 beat). This MIDI data is critical. It creates the "rising" sensation. The notes aren't changing, but the rhythmic subdivision is, which tricks the brain into hearing movement where there is stasis.
In the original track, the tempo literally increases. It starts around 126 BPM and accelerates to 132 BPM by the climax. Most DAWs allow you to automate the master tempo. If your MIDI clip is fixed, stretch it via "Warp" (Ableton) or "Time Stretch" (FL Studio) to match the accelerating grid.