The 17-field anatomy of a prompt that works on Suno v5.5
Most "how to write a Suno prompt" guides give you the same advice: be descriptive, mention the genre, specify a key. That works for Suno v3 and v4. It doesn't work for Suno v5 / v5.5.
The v5 parser was rebuilt around structured semantic anchors. When you give it a wall of natural language, it averages every word into a soft, generic interpretation. When you give it a JSON object with named fields — kick, bass, perc, vox, atmosphere — the parser locks each field to a specific sonic decision. The output goes from 5/10 to 9/10 with zero extra creativity on your part.
This guide is the cornerstone reference for the GENPROMPT prompt anatomy: a 17-field JSON contract that produces reproducible, high-fidelity Suno v5.5 tracks across funk, hardstyle, reggaetón, and any genre you want to target.
Why structured prompts beat plain text by 2x
The GENPROMPT team ran 100 paired generations (50 plain text + 50 JSON, identical content) across 12 sub-genres in Suno v5.5. The empirical results:
- Genre fidelity — JSON: 87 percent match. Plain text: 41 percent.
- Sound design retention — JSON: 78 percent. Plain text: 23 percent.
- Vocal style match — JSON: 73 percent. Plain text: 38 percent.
- Negative compliance — JSON: 91 percent. Plain text: 52 percent.
The mechanism is straightforward: Suno v5's parser appears to use JSON keys as attention anchors. The key kick forces a kick decision separately from the key bass. In plain text, "with a deep kick and rolling bassline" gets averaged into a single low-end blob.
The 17 fields, in order of importance
Sort the 17 fields by impact on output quality and you get this priority order. If you only have time to fill in 5 fields, fill in 1–5. The rest add polish and reduce variance.
1. style (highest impact)
The sub-genre + era + region triple. Not "house music" — instead "Detroit techno warehouse 1992 acid-tinged minor key". Specificity is everything.
Bad: "style": "edm" Good: "style": "Berlin minimal techno 2010s mainfloor 128 BPM acid 303 line"
2. kick
The most determinative single sonic element. Describe it in four stages: attack click, body, tail, sub layer.
Bad: "kick": "hard kick" Good: "kick": "sharp 2kHz attack click, warm 80Hz body, 600ms saturated tail, A0 27Hz sub layer"
3. bpm
Integer. Suno parses the number and locks the grid. "bpm": 128 works. "around 128 BPM" introduces variance.
4. key
Musical key in a parseable format. "key": "F minor" is unambiguous. "minor key dark" is not.
5. bass
The low-frequency layer beneath the kick. In some genres (hardstyle dark tekk, raw hardstyle) there is no separate bass — the kick's sub layer IS the bass. Tell Suno explicitly: "bass": "no separate bass, kick is the entire low end" or it will add a redundant 808.
6. perc
Secondary percussion. Hi-hats, snares, claps, congas, woodblock, tamborim — whatever shapes the groove beyond the kick. Include rhythmic positions ("on 2 and 4", "16th hats", "off-beat woodblock").
7. vox
Vocal treatment + language + accent. "vox": "male Spanish PR accent, rapid-fire flow, slap-back delay 80ms" beats "vox": "vocals" by an order of magnitude.
8. atmosphere
The room sound. Cathedral reverb, warehouse smoke, outdoor block party, car interior, intimate bedroom — Suno has learned timbral palettes for each.
9. melody
The lead instrument character. Specify the synth or instrument family ("metallic phonk cowbell loop, distorted bit-crushed", "acoustic guitar arpeggios, minor key").
10. drop
Bar position where the main groove enters. "drop": "bar 1 beat 1" (immediate) vs "drop": "bar 16" (delayed with intro). Most-ignored, highest-impact.
11. arrangement
Section flow. "arrangement": "intro 4 bars, drop bar 1, beat-switch bar 16, outro tag bar 28" is a road map Suno follows.
12. anch (cultural anchor)
Geographic + temporal pin. "anch": "favela paulista 2024, montagem omega scene" tells Suno which regional sonic dialect to pull from.
13. swing
Micro-timing feel in percent. "swing": "9 percent swung pocket" beats "swing": "loose feel". The number is parseable.
14. sub
Sub-bass identity with frequency range. "sub": "A1 55Hz pure sine, never modulated" tells Suno exactly which oscillator to summon.
15. mix
Dynamics target with LUFS reference. "mix": "sub-heavy LUFS -8, kick clips to ceiling, vocals dry" gives Suno a mastering target.
16. length
Track duration target. "length": "90 seconds" or "length": "2 minutes". Affects arrangement length and section pacing.
17. fx (the polish field)
Effects, transitions, risers, downlifters. "fx": "white noise riser bar 14-16, downlifter bar 16, tape stop transition bar 32". Optional — add when you want studio-style transitions instead of hard cuts.
Copy-paste template: the universal 17-field skeleton
{
"style": "[sub-genre + era + region]",
"length": "[duration]",
"bpm": [number],
"drop": "[bar position]",
"key": "[musical key]",
"kick": "[attack + body + tail + sub layer]",
"bass": "[bass layer, or 'kick is the bass']",
"perc": "[secondary percussion + rhythmic positions]",
"anch": "[cultural / geographic anchor]",
"swing": "[swing percent]",
"sub": "[sub-bass identity + Hz range]",
"vox": "[vocal style + language + accent]",
"atmosphere": "[room sound]",
"melody": "[lead instrument character]",
"arrangement": "[section flow with bar numbers]",
"mix": "[dynamics + LUFS target]",
"fx": "[transitions + risers + downlifters]"
}Drop this directly into Suno v5.5's Style field. The parser handles raw JSON — no need to flatten it.
Worked example: a 130 BPM dark techno track
{
"style": "Berlin dark techno underground 2024 raw industrial 130 BPM minor",
"length": "2 minutes",
"bpm": 130,
"drop": "bar 1 beat 1",
"key": "C minor",
"kick": "sharp 1.5kHz click, warm 70Hz punch, 400ms reverb tail, C1 32Hz sub layer continuous",
"bass": "no separate bass, kick sub IS the bass",
"perc": "metallic clap on 2 and 4, hi-hat 16ths slightly swung, ride bell on offbeat",
"anch": "Berlin Berghain underground 2024, raw industrial scene",
"swing": "3 percent swing, almost locked",
"sub": "C1 32Hz pure sine continuous under kick",
"vox": "no vocals, occasional whispered female sample at bar 64",
"atmosphere": "concrete warehouse, smoke machine, strobe lighting cold",
"melody": "minimal acid 303 line, modulated cutoff, dark minor third",
"arrangement": "intro 16 bars build, drop bar 16, breakdown bar 64 acid solo, second drop bar 80",
"mix": "kick + sub dominant -7 LUFS, mids carved, treble percussive only",
"fx": "white noise riser bar 14-16, sub drop bar 16, reverse cymbal swell bar 64"
}This 17-field structure produces a convincing Berlin underground techno track in Suno v5.5 with one generation. Fewer regenerations, less editing, more usable output.
What to do when you don't know all 17 fields
Don't fake it. Skip the fields you don't have an opinion about — Suno fills them with reasonable defaults based on the style + bpm + key triple. The 5 must-fill fields:
- style (sub-genre + era + region)
- bpm (integer)
- key (musical key)
- kick (the four-stage anatomy)
- vox (or "no vocals" if instrumental)
The other 12 fields polish and reduce variance. Add them as your prompt-engineering muscle grows.
Common mistakes that ruin a 17-field prompt
1. Real artist names. Suno v5.5 silently filters proper nouns of artists, producers, song titles, and labels. Phrases like "in the style of [famous artist]" get replaced with random instruments. Use sub-genre + era + region instead.
2. Asking for three or more genres. "Reggaetón hardstyle phonk fusion" produces averaged mush. Pick one primary + at most one fusion partner.
3. Vague kick descriptions. "Hard kick" is not a kick. Always specify attack click + punch body + distorted tail + sub layer with frequency ranges.
4. Skipping the cultural anchor. "Funk montagem" alone is ambiguous between São Paulo, Rio, and Bahia variants. The anch field disambiguates.
5. Letting the prompt exceed 1000 chars. Suno truncates the style field at 1000 chars without warning. A complete 17-field prompt typically lands at 800-950 chars. Compress when needed.
Skip the manual JSON — use the GENPROMPT generator
Writing 17-field JSON by hand for every track is tedious. The GENPROMPT prompt generator emits a complete 17-field JSON in seconds across 32 specialized modes — pick the genre, click generate, paste into Suno. The free plan includes 35 generations per day with no signup.
For batch workflows (10 prompts at once, mass A/B testing across sub-genres) the Pro plan unlocks unlimited generation and parallel-mode generation.
Conclusion
The 17-field JSON structure is the difference between Suno v5.5 producing a 5/10 generic track and a 9/10 genre-locked anthem. JSON beats plain text by 2x on every measurable dimension. Specify the kick in four stages, anchor with era + region, and commit to one primary genre per prompt.
This structure is the foundation of every output produced by the GENPROMPT generator — try it free at /generator with no signup required.
