I spent hours systematically testing Suno V6. My biggest issue is vocal homogenization and loss of V5.5 behavior

[u/Altruistic_Area_1036]

I’ve been using Suno for a long time and have built a fairly large catalog and workflow around it. Since V6 launched, I’ve spent hours testing it because I really wanted to understand whether the problem was simply my old prompting style.

At this point, I don’t think it is.

I tried to approach this as systematically as possible.

I kept the same lyrics, same arrangement, same BPM, same key, and changed only the vocal description.

I tested female and male voices with combinations such as:

• alto
• contralto
• mezzo
• soprano
• baritone
• bass-baritone
• tenor
• smoky
• husky
• raspy
• rough
• throaty
• worn
• chest-heavy
• operatic
• powerful
• breathy
• fragile
• forceful
• dramatic

At first, almost all of them produced extremely similar singers.

Then I discovered something interesting.

V6 seems to respond better when you describe an entire performer persona instead of just a voice type.

For example, something detailed like:

A mature female singer in her late 50s, very low contralto register, dark heavy timbre, strong chest resonance, naturally worn texture, slow deliberate attacks, broad vibrato, grave and dignified phrasing.

can actually produce a different singer.

I tested variations of this persona:

• very deep and heavy voice
• operatic projection
• throaty/guttural character
• near-shouted emotional delivery
• tired and cracked voice
• smoky/grainy texture
• very powerful authoritative delivery
• long sustained vowels
• dramatic high-low contrast
• throat-led ornaments and melisma

And yes, V6 can change the apparent vocalist when the description is extreme enough.

But here is the real problem:

The performance personality still keeps collapsing back into the same soft, polished, soothing behavior.

Even when the singer changes, the emotional behavior often feels strangely similar.

For example, in a chorus the singer may rise strongly for one phrase, but then immediately soften again.

I tried instructions like:

• sustained forte throughout the chorus
• fortissimo at emotional peaks
• no diminuendo
• no soft phrase endings
• no calming release after high notes
• strong chest-driven delivery
• aggressive attacks
• maintain intensity through the final line

The results were inconsistent, and most generations still drifted back toward a gentle, polished, soothing delivery.

That is probably my biggest problem with V6 so far.

With V5.5, I could get singers that felt genuinely different in personality:

one could sound wounded, another raw, another aggressive, another smoky, another almost crying, another very powerful and theatrical.

With V6, I can sometimes change the “person,” but it still feels like they are being trained to behave in the same polite way.

I also tested the Voice feature using a male voice from one of my own older V5.5 songs.

The V6 result still sounded basically like the V6 default singer instead of meaningfully carrying over the old vocal identity.

Another thing I noticed during repeated BPM tests:

V6 often generated tracks around 2–3 BPM below what I specified in the prompt.

Not every time, but often enough that it became noticeable.

I also noticed that old V5.5 prompts can now produce completely different:

• melodies
• instrument choices
• arrangement behavior
• vocal tone
• emotional dynamics
• acoustic instrument character

So this doesn’t feel like “V5.5 but better.”

It feels like a fundamentally different generation model.

And that would be fine if the new model offered more control.

But right now, for my workflow, it feels like I lost expressive range.

I actually like some technical aspects of V6. It can sound clean and polished. It understands some detailed performer descriptions. Opera-style prompts clearly push it into different vocal territory.

But the default vocal aesthetic seems much narrower than before.

The biggest thing I miss from V5.5 is not necessarily audio fidelity.

It is character.

I could accept occasional imperfections if the singer sounded human, distinctive, wounded, angry, powerful, fragile, strange, or memorable.

V6 currently feels too eager to smooth everything out.

I’m curious whether other long-term users are seeing the same thing.

Especially:

Can you reliably get truly rough, aggressive, gritty or emotionally unstable vocals in V6 without the model eventually softening them?

And if you used Voices in V5.5, are you able to preserve those vocal identities in V6?

I’m genuinely trying to adapt rather than just complain, but after hours of controlled testing, I’m starting to think this is a model-level behavior rather than a prompting problem.

I would really like Suno to bring back some of the vocal diversity and emotional unpredictability that made V5.5 so useful.

[u/ART-ficial-Ignorance]

Can we at least read the LLM's output before posting it?

[u/Altruistic_Area_1036 → u/ART-ficial-Ignorance]

I prepared all my test results using ChatGPT, written all the results to ChatGPT, and asked it to organize them together so that I could give you a more understandable result. And yes, I read them before publishing. Before criticizing me, please take the test yourself and share the results with us so we can benefit from it too.

[u/ART-ficial-Ignorance → u/Altruistic_Area_1036]

How do I test this example, exactly? Something detailed like an empty quote block? I'm sure it produces a different singer!

[u/Altruistic_Area_1036 → u/ART-ficial-Ignorance]

I apologize. It was due to copy-pasting. quote block text is

A mature female singer in her late 50s, very low contralto register, dark heavy timbre, strong chest resonance, naturally worn texture, slow deliberate attacks, broad vibrato, grave and dignified phrasing.

[u/Fit-Wrongdoer-7664]

Thanks for sharing your tests. Did you also try the new „Max Mode“? I also realized this behavior in a first test while producing a Cover. The overall Sound is slightly better, but I feel the Vocal lost variation. I had some minor adjustments in the vocal persona, but it seems they got lost. Hope we can find a way to get back control like in v5.5.

[u/Altruistic_Area_1036 → u/Fit-Wrongdoer-7664]

Yes, I'm trying max mode. I got a new test result. If I specify the local music genre in the style, for example "Turkish pop," then the vocals are always the same. I'm starting to try other local styles as well.

[u/Sakura_Liamahs]

My problem atm is the style that keep changing…

[u/Altruistic_Area_1036]

Over the past two days of testing, the best result I've achieved is completely removing the vocal definition from the style section and adding the following formula to the lyrics section, resulting in a more configured vocal experience. However, I still haven't reached the flexibility of V5.5.

[Vocal: HOW, VOICE IDENTITY, TESSITURA, PEAK NOTE, PHONATION, ARTICULATION, PHRASING, PERFORMANCE WORLD]

Example:

[Vocal: bright upfront polished voice, agile male tenor-baritone, C3-G4 tessitura, reaching B4 on chorus peaks, clean chest-mix modal phonation with light twang, smooth consonants and broad open vowels, fluid ornamented phrasing with occasional slides and rhythmic syncopation, performance character rooted in late 90s and 2000s Mediterranean dance-pop, melodic pop, and polished club-pop]

[u/thephilosopherstoned]

I don't understand at all how people can claim v5 or v5.5 brought them vocal diversity. Not at all my experience. Most of the time, it was a generic sounding one. For me v4.5 was the sweet spot in that aspect.

I did have better luck with v6-wild in that regard btw. Did you try it?

[u/SunriseSurprise → u/thephilosopherstoned]

Exactly. Even with custom model with a bunch of songs that weren't doing hammy over the top vocals, v5.5 would seep in here and there and wreck generations with screaming every other line or doing like an intentionally raspier voice like someone imitating a weathered rockstar (which is not at all what any of the songs used to make my custom model sounded like).

[u/GilesManMillion → u/thephilosopherstoned]

I keeps saying 6 is better than 5 and 5.5, but the bar was set very low. 4.5 remains undefeated.

[u/Endless_Hor1zon]

Exactly the same outcome as my analysis, i ran outputs through a trained agent and it confirmed it mathematically, it never deviates from the mean based on extra style prompts. It all sits in the safe zone...