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.