By SongTools.ai
Every genre has a harmonic fingerprint, not just a drum pattern. Here's what actually makes lo-fi, trap, and bedroom pop sound the way they do, with real progressions to build from.
Producers obsess over drum patterns and sound design as genre signifiers, but chords do just as much of that signaling work, arguably more. Put a distinctly lo-fi chord progression under trap drums and 808s, and the track reads as a hybrid, not straightforwardly either genre. Some harmonic choices are simply far more idiomatic to a given genre than others, and knowing what those choices actually are makes genre-specific prompting far more effective than just naming the genre and hoping.
Lo-fi's harmonic fingerprint borrows heavily from jazz but simplifies and slows it down: major 7th and minor 7th chords instead of plain triads, frequent short ii-V-I motion, and a harmonic rhythm that moves much slower than the beat itself, a two- or four-chord loop repeating for an entire section is the norm, not a placeholder.
A representative loop: Dm7 → G7 → Cmaj7 → Am7, a classic ii-V-I-vi cycle, just voiced with sevenths instead of bare triads and looped rather than developed. Dorian or Mixolydian modal color shows up often too, giving that specific lo-fi quality of sounding neither fully happy nor fully sad.
Trap's harmonic fingerprint is almost the opposite of lo-fi's constant gentle motion: predominantly minor keys, minor 9th or suspended tension chords for a darker color, and, most distinctively, genuinely static harmony. A single chord, or a two-chord loop, sustained across an entire section is extremely common, because in trap the melodic line and the 808 bassline are doing the harmonic movement work, not the chord progression itself.
A representative example: Cm9 sustained for a full section, or a simple Cm → Ab (i → VI) loop underneath a moving melody and 808 pattern. The chords aren't meant to be the interesting part; they're a dark, stable bed for everything else to move against.
This genre's fingerprint sits in major keys but deliberately avoids feeling fully resolved: added-2nd and suspended chords instead of plain triads, and progressions that land on the IV or vi chord instead of returning cleanly to the I, creating that wistful, diaristic quality the genre is known for. Complexity usually stays low; heavy chorus and reverb do a lot of the harmonic "color" work that denser chord voicings would do in other genres.
A representative loop: G → D/F# → Em → Cadd9, mostly simple triads, but the added 9th on the final chord and the descending bass line keep it from ever feeling fully settled.
When prompting MIDI Generator for a specific genre, naming the genre alone often isn't precise enough, being explicit about the extension type (maj7, m9, add9, sus2) and whether the harmony should stay static or keep moving gets you noticeably closer to the idiomatic sound than "trap chords" or "lo-fi chords" on their own. The genre name tells the model a general direction; the extension and movement language tells it the specific texture.
These are fingerprints worth knowing, not rules to follow every time. Some of the most interesting tracks in every one of these genres deliberately break the pattern, a trap beat with genuinely moving harmony, a lo-fi track with none of the expected jazz extensions. Treat this as a starting vocabulary that helps you recognize what's idiomatic, so that breaking from it is a choice you're making on purpose rather than an accident of not knowing the convention existed.
Q: Why do trap beats often use just one or two chords for the whole song?
A: Because in trap, the melody and the 808 bassline carry the harmonic movement and interest, not the chord progression. Static harmony gives them a stable, dark bed to move against without competing for attention.
Q: What makes a chord progression sound distinctly "lo-fi"?
A: A combination of extended 7th and 9th chords borrowed loosely from jazz, a slow harmonic rhythm (chords changing much less often than the beat), and modal color from scales like Dorian or Mixolydian rather than plain major or minor.
Q: Can I use these exact example progressions in my own track?
A: Yes, chord progressions aren't protected by copyright the way a specific melody or lyric is, so using a common genre-idiomatic progression like these is standard practice, not something requiring permission.
Q: Does naming the genre in a prompt actually change a generator's output?
A: It helps, but being explicit about extension type and whether the harmony should feel static or moving gets you noticeably closer to the idiomatic sound than the genre name on its own.
All the tools discussed in this article are available on SongTools.ai, free to explore.