How does Suno know which voice sings which line?
Suno reads two things separately: the style box describes the sound, and the lyrics box decides who sings what. Put a short label before each line, such as "Him:" and "Her:", or "Male:" and "Female:", inside your normal section tags like [Verse 1] and [Chorus]. Keep the labels short and consistent throughout the song, since switching labels partway through (from "Him:" to "Guy:") can confuse which voice a line belongs to.
Section tags such as [Verse], [Chorus], [Bridge] and [Instrumental] are a common convention that models follow often but not always, so treat the labelling as a strong hint rather than a guarantee.
What tempo and key work best for a pop duet?
Most duets sit in the same range as general pop: 90 to 130 BPM, most often 100 to 125 BPM, in a major or minor key over a simple four-chord loop. C major, G major and A minor are common choices. A slower duet (70 to 95 BPM) suits a ballad with more space for two voices to trade lines without rushing.
- Faster tempo (115 to 130 BPM): energetic, call-and-response duets
- Mid tempo (95 to 115 BPM): standard verse-and-chorus duets
- Slower tempo (70 to 95 BPM): ballad-style duets with a big harmony ending
Should I describe both voices or just one?
Describe both. Naming only one voice often leaves the model to guess the second, and it may default to a similar tone rather than a contrasting one. Use timbre words for each: "deep male voice" and "breathy female voice", or "raspy male voice" and "smooth female voice", so the two are clearly different in the mix.
Reliable vocal descriptors include male, female, whisper, raspy, breathy and belting. Words like falsetto or vague terms such as "smooth" are less predictable, so treat them as a rough steer rather than a guarantee.
How do I get the harmony to land on the chorus?
Say explicitly in the style box where the harmony happens, for example "harmony on chorus" or "both voices harmonising in the bridge". This tells the model when to blend the two voices rather than keep them separate throughout. Pair it with a lyric line labelled "Both:" at the same point so the text and the style instruction agree.
Overusing harmony instructions (harmony on every section) tends to blur the two voices together for the whole song, so save the label for the one or two sections where you want it.
Lyrics skeleton
Original, for structure
[Verse 1] Him: I kept the porch light burning low Her: I saw it from the road, you know [Verse 2] Her: You never said the words out loud Him: I said them in the way I stayed [Chorus] Both: We're still here, still turning round Both: Two voices making one sound
Common mistakes
- Naming only one voice and letting the model guess the second: describe both voices with contrasting timbre words.
- Using different singer labels in different verses (Him: then Guy:): pick one label per singer and keep it the whole song.
- Piling on more than two or three moods at once (tense, romantic, aggressive, dreamy): pick one or two moods that do not contradict.
- Forgetting to mark the harmony section in both the style box and the lyrics: label it in the lyrics as Both: and mention it in the style box.
- Writing very long lines for two voices to trade: keep traded lines short so the handoff between singers is clear.