Sony Music Entertainment and Universal Music Group have filed a second copyright lawsuit against Suno, this time challenging the training of its new v6 music models. The September 18 complaint alleges that v6 inherited material from earlier Suno models trained on the labels’ recordings without permission. Suno disputes the lawsuit’s factual and legal claims.
The labels call this theory “model laundering.” Their complaint says Suno used songs made by earlier models, along with data about which generated songs users preferred, to train v6. It also alleges that Suno used knowledge distillation, in which a new model learns to reproduce the behavior of an earlier one. Those are allegations about v6’s development, not findings by the court.
What Suno has said about v6
Suno launched v6 on September 9 and said it developed the model family with Warner Music Group, BMG, and Believe. Its launch post does not give a full list of training inputs. Suno later told The Verge that v6 was trained on licensed partner content, community interactions including user “creations” and preference signals, and its team’s accumulated work. The company did not tell The Verge whether that included uploaded audio or outputs based on uploaded audio. In a separate response reported by Music Business Worldwide, Suno called the new claims “fundamentally flawed on both the facts and the law.”
That distinction matters. Suno has acknowledged using user creations and preferences, but has not publicly supplied enough detail to establish which earlier outputs entered the training set or whether it distilled v6 from prior models. The complaint asserts both a path through generated audio and a path through model behavior. Neither has been established in this case.
The new suit names 60,202 recordings and follows the labels’ original 2024 case against Suno. The complaint seeks damages and a court order restricting further use of the recordings. The number counts works the labels assert in this action; it is not a court finding that Suno infringed each one.
