DEV Community: samuel pier

The 9 genres where BPM doesn't apply — and what to write instead

samuel pier — Wed, 16 Sep 2026 00:39:31 +0000

There is a field in every AI music generator that looks compulsory and isn't. Tempo. You type a number, the model builds a grid, and everything you wrote gets laid across it. For 555 of the 564 styles in this catalogue that is exactly what you want. For nine of them it is the single fastest way to destroy the track before the first bar.

These are the free-time genres: Dark Ambient / Sound Art, Drone Experimental, Electroacústica, Música Aleatoria, Musique Concrète, Noise, Power Electronics, Señal Sin Nombre and Sound Collage. They have no pulse. Not a slow pulse — none. The absence is the genre's whole proposition, and a number in the tempo field contradicts it before the model has read a single word of your lyric.

Disclosure: I built and maintain the catalogue these numbers come from. It is public domain (CC0), published as CSV, JSON and Parquet, so everything below can be checked against the source rather than taken on trust.

The data-hygiene trap that hides them

Until recently these nine were stored in my own dataset as BPM 0, and that is worth admitting because it is the most common way this problem propagates. Zero is not a description of anything. It is a number that means "we had nowhere to put this", and it does two kinds of damage.

It sinks your averages: nine zeros dragged the catalogue's mean tempo down by about two beats per minute, quietly, in every calculation anyone ran on the file. And worse, it is copyable. Someone reads the row, sees 0, pastes 0 into the tempo field, and the generator does not interpret that as "free time" — it treats it as an invalid input and falls back to its default, which lands somewhere near 120. You asked for Musique Concrète and got Musique Concrète with a house beat under it.

They are now an empty cell in the CSV, null in the JSON and a dash in the Markdown table. If you ever build on a genre dataset, check how it encodes absence before you trust a single average it produces.

The surprise in the numbers

The intuition is that genres without tempo are the loose ones. Free time, free rules, anything goes. The catalogue says the opposite.

Across all 564 styles, style influence — how tightly the model is held to the genre — has a median of 92. These nine sit at a median of 91, ranging from 89 to 95. They are as tightly bound as the rest of the catalogue. Not loose at all.

What is unusual about them is the other slider. Their weirdness runs 66 to 80, median 72, against a catalogue median of 26. And all nine belong to a single family.

Put those two facts together and you get the actual instruction, which is not intuitive: these genres want maximum strangeness held under maximum constraint. They are not a licence to be vague. They are a very specific tradition of being strange, and the model knows that tradition. Loosen style influence "because it's experimental" and you do not get a freer piece — you get a generic ambient wash, which is what the model reaches for when nothing holds it.

What replaces the meter

Here is the part nobody tells you. Losing tempo does not mean losing structure. It means swapping one kind of structure for another.

Look at the canonical section structures for these nine and the same shape appears every time:

Style	Structure
Noise	Noise emergence → feedback layers → sonic wall → abrasive climax → decay
Drone Experimental	Opening tone → layering → slow transformation → peak density → decay
Musique Concrète	Concrete sound → manipulation → tape montage → abstract development → spatial resolution
Sound Collage	Spoken fragment → field sound layers → narrative juxtaposition → dense climax → silence
Power Electronics	Brutal emergence → feedback layers → overwhelming wall → visceral climax → abrupt cut

Five stages, every time: something emerges, it accumulates, it reaches maximum density, it resolves.

That is a dramatic arc rather than a metric one. Verse and chorus are measured in bars; this is measured in pressure. So when you write for these genres, you are not writing lines to fit a grid — you are deciding at which point in a rising density your words arrive, and at which point they stop.

Practically: give yourself five movements, not four verses. Decide what enters first and let it be small. Decide what the maximum is. Decide whether it decays, resolves, or gets cut off — Power Electronics ends on an abrupt cut, Sound Collage ends in silence, and those are different endings for your last line, not decoration.

Repetition stops being rhythmic and becomes textural

In a song with a pulse, a repeated line lands on a beat, and the beat is what makes the repetition feel intentional. Take the pulse away and repetition has to justify itself some other way.

The answer these genres have used for seventy years: repetition becomes texture. A phrase repeated without a grid does not feel like a hook, it feels like an accumulation — each return is slightly buried under what has been added since, so the line is not restated, it is eroded.

That changes how you write the line. A hook is built to survive being heard identically twenty times. A textural phrase is built to change meaning as it gets harder to hear. Which means: write a line that is still legible at 30% audibility, and make it one that gets more ambiguous as it degrades, not less. Short vowels. Concrete nouns. No clause that depends on a word arriving intact at the end.

And where the tempo field can't help you, the negation moves into the style prompt. The catalogue entries for these genres carry it explicitly — Noise's prompt literally contains "no rhythm", Música Aleatoria's carries "indeterminate timing" and "silence as composition". That is where you tell the model there is no grid. Not in a number.

The two mistakes, every time

One: writing to an implied beat anyway. Most writers count syllables out of habit, so the lines come out metrically even. Over free time, even lines sound like a pop song with the drums muted — the grid is audible precisely because it is missing. The fix is to write in breath-lengths instead of syllable-counts. Let one fragment be two words and the next be nineteen. Unevenness is not sloppiness here; it is the only thing that proves there was never a grid.

Two: confusing "no pulse" with "no shape". This is the more common and more fatal one. Without a chorus to aim at, writers produce a mood board — six atmospheric images in a row, none of which arrives, because nothing was built up to. The five-stage arc above is the fix, and it is not optional. A piece of Dark Ambient that never reaches peak density is not restrained. It is unfinished.

What the settings still won't solve

Empty the tempo field, hold style influence at 91, push weirdness past 70, and you will get a convincing texture. You will not get a convincing lyric — because the hardest question in these genres is not what the track sounds like, it is how much can be left unsaid before the words stop meaning anything at all.

That is a writing problem, it is different in every one of these nine, and no slider reaches it. Each style in the catalogue carries a craft note naming its own version of it — the full pages for Musique Concrète and Sound Collage are a good place to see what that looks like in practice.

The full catalogue of 564 styles — style prompt, BPM, weirdness, style influence and canonical song structure for each — is public domain under CC0 1.0, as CSV, JSON and Parquet, and mirrored on Hugging Face. Every style also has a full page: https://musaisong.app/en/styles

Part one of this series, on what the corpus reveals about the two settings that matter most, is here.

What 564 documented genres reveal about how Suno's settings actually behave

samuel pier — Tue, 15 Sep 2026 23:56:09 +0000

Most advice about Suno's generation settings is handed down rather than measured. You are told to keep weirdness somewhere around 20 to 40 and style influence somewhere around 70 to 90, and then you are left to work out the rest by burning credits. The advice is not wrong exactly. It is just untested, and when you test it against a large enough corpus, parts of it turn out to describe a space that does not exist.

This is what happens when you read 564 documented music styles as data rather than as a lookup table. Each style in the catalogue carries a style prompt, a tempo, a weirdness value, a style influence value and a canonical song structure, grouped into 18 families. The whole thing is public domain, published as CSV, JSON and Parquet, so every number below can be checked against the source in about two minutes rather than taken on trust.

Disclosure: I built and maintain this catalogue. It exists because I needed it for a paid product that writes song lyrics, and the settings table turned out to be the part worth giving away. The numbers are not marketing claims; they are the inputs I use, and they are falsifiable. If you find a row that is wrong, the repository has an issue template for exactly that.

Style influence is a floor, not a dial

Here is the finding that changed how I write prompts. Across all 564 styles, style influence runs from 78 to 100. The median is 92. Eighty per cent of the catalogue sits at 90 or above. Exactly two styles in the entire set fall below 80, and both are in the same corner of hip-hop.

Now look again at the common advice: set style influence between 70 and 90. Between 70 and 77, the catalogue contains zero styles. Not few — none. A third of that recommended band describes settings that no documented genre in this corpus uses, which means the advice is quietly calibrated against a 0-to-100 scale that has no practical existence. The working range is roughly 22 points wide, and it sits almost entirely in the top fifth of the slider.

The consequence is a matter of step size. If you think you are working with a 100-point scale, dropping style influence by 10 feels like a nudge. Against a 22-point working range, 10 points is close to half the usable scale, and it is enough to move a generation from "this genre" to "something adjacent that I did not ask for". When people report that lowering style influence for a bit of creative freedom produced an unrecognisable track, this is the arithmetic behind it. They did not loosen the constraint. They removed it.

The practical rule that follows: move style influence in steps of two or three, not ten. And when output feels generic, raise it before you touch anything else. Generic output is usually a symptom of under-constraint, not of insufficient strangeness.

The two settings move together, but only halfway

Weirdness and style influence are correlated at -0.455 across the 564 styles. Negative, which is intuitive: the more a genre is defined by convention, the less room there is to be strange inside it. Mariachi Tradicional sits at weirdness 9 and style influence 100. Bolero Clásico is at 12 and 99. These are genres whose audiences know the rules by heart, and where surprise reads as a defect rather than as personality.

But -0.455 is the interesting part, not the minus sign. A correlation of that size means the two settings explain only about a fifth of each other's variation. They move together roughly half the time and go their own way the rest of it. So the mental model of a single "conventional to experimental" slider, with the two settings locked together on it, is wrong — and it is wrong in a way you can see directly in the data.

Take every style in the catalogue with weirdness at exactly 60, the same deliberately high value. Rage sits at style influence 80. Hyperpop sits at 95. Both are asking the model for maximum strangeness. They are asking for it under completely different conditions: Rage wants strangeness and permission to drift away from the genre, while Hyperpop wants strangeness held tightly inside a form that is itself very specific. Fifteen points apart on a 22-point working range is not a nuance. It is the difference between a track that wanders and a track that detonates on purpose.

The same pattern appears at weirdness 58: Cloud Rap at style influence 78, Fourth World at 93. Equally strange on paper, and the second one is pinned to its genre while the first is allowed to dissolve.

This is why the generic 50/50 starting point gives the worst of both. It sets style influence to a value no documented style uses, and weirdness to a value that only 46 of the 564 styles exceed, so it lands in the gap between a genre you can recognise and an experiment you chose on purpose. If you want strangeness, decide separately whether you want it held or released. That second decision is the one the single-slider model hides.

One more thing worth knowing about weirdness: above 50 it stops being a setting and starts being a genre. Only 46 styles in the whole catalogue go there, and they cluster almost entirely in the noise and experimental family — Noise at 78, Power Electronics at 80, Musique Concrète at 74, Breakcore at 70, Sound Collage at 70. If you are writing a pop song and you push weirdness to 60 for a bit of character, you are not adding character. You are requesting membership in a club with 46 members, and yours is not one of them.

When tempo does not apply

Tempo in the catalogue runs from 45 BPM to 220, with a median of 100, and it is the least mysterious of the three settings: it does exactly what it says. The instructive case is the exception.

Nine of the 564 styles carry no tempo at all. Dark Ambient, Drone Experimental, Electroacústica, Música Aleatoria, Musique Concrète, Noise, Power Electronics, Señal Sin Nombre and Sound Collage are free-time. There is no pulse to set, because the absence of one is the genre's entire proposition.

This is a small detail with a large data-hygiene lesson attached. Those nine styles were originally stored as BPM 0, and 0 is not a description of anything — it is a false number that quietly drags down every average you compute and, worse, gets pasted into a prompt where it means nothing. In the published dataset they are now an empty cell in the CSV, null in the JSON and a dash in the Markdown table. If you build anything on top of a genre dataset, check how it encodes absence before you trust its means.

The practical version: for these nine, leave the tempo field alone. Setting a BPM does not make them faster. It makes them wrong.

What the three settings do not solve

Here is the limit of everything above. The settings get you the sound. They do not get you the lyric, and the lyric is where most AI songs come apart — because a language model will cheerfully produce a technically correct chorus that any genre could have produced.

No combination of BPM, weirdness and style influence will stop a soul ballad from sliding into melodrama, keep a cumbia from sounding like a beer advert, or prevent a repetitive techno lyric from going flat on the fourth pass. Those are writing problems, they are specific to each genre, and they sit entirely outside the three numbers. Each style page in the catalogue carries a craft note naming the one writing problem that style creates, which is the part of the work the settings cannot reach: https://musaisong.app/en/styles

The settings are the easy half. They are worth measuring properly precisely so that you stop blaming them for the hard half.

The full catalogue of 564 styles — style prompt, BPM, weirdness, style influence and canonical song structure for each — is public domain under CC0 1.0, as CSV, JSON and Parquet, and mirrored on Hugging Face. Repository: https://github.com/samuelgrupolimex-prog/suno-style-recipes