The consequences of the outcome of the trial could extend to the rest of musical creation, at the risk of "chilling" artists, warn some musicologists and lawyers.

A jury in federal court in Manhattan must determine whether the 2014 global hit, Ed Sheeran's "Thinking Out Loud," is plagiarism of the Prince of Soul's famous "Let's Get It On" in 1973.

The plaintiffs, in this emblematic case for music copyrights, are the heirs of Ed Townsend, an American musician and producer who co-wrote the song with Marvin Gaye.

They point to "striking similarities and overt common elements" between the two songs.

This is the second trial in a year for the 32-year-old British singer and songwriter, who won a separate legal battle in April 2022 at the High Court in London, which rejected two musicians accusing him of copying one of their works for his mega hit "Shape Of You".

Guitar in court

Sheeran, who has been attending the New York hearings since April 24, even had to play guitar and sing in the courtroom as a token of good faith.

Quoted by the prosecution, a musicologist said that the chord progression on the two pieces was almost identical.

The pop musician played in court the four key chords of "Thinking Out Loud", ensuring that they were very different from those in "Let's Get It On".

The British artist also said he wrote his hit in 2014 with his musical partner Amy Wadge while "getting out of the shower" at home. The song reached number two on the Billboard Hot 100 and won the Grammy Award for Best Song in 2016.

The risk of the Sheeran trial, experts fear, is the multiplication of conflicts over copyright and a form of "paranoia" that would develop among musicians terrified of copying each other.

"Pure coincidence"

"The world I want to live in is one where no one sues anyone for melodic or harmonic similarities, because they can easily happen by pure coincidence," Joe Bennett, a musicologist at Berklee College of Music in Massachusetts, told AFP.

"It should not fall under copyright protection," he said.

Especially since appreciating the composition and interpretation of a musical title is particularly subjective: "If you play in front of a jury, it can go one way or another," warns Mr. Bennett.

The work of the king of the Motown label, African-American Marvin Gaye (1939-1984) had already been the subject of a complaint when his family -- who are not parties to the Sheeran lawsuit -- won against artists Robin Thicke and Pharrell Williams for similarities between the songs "Blurred Lines" and "Got To Give It Up".

This surprised the music industry and legal scholars who consider many melodic and harmonic elements to be in the public domain.

"Stairway to Heaven"

Much better known, the case "Stairway to Heaven" where the famous British hard rock band Led Zeppelin had triumphed against a Californian formation, the American justice judging in 2020 that the mythical title of 1971 was not plagiarism.

But for Joseph Fishman, a professor of intellectual property law at Vanderbilt University, the Sheeran case risks setting a precedent.

"It can chill songwriters in their way of writing: +Will my case end up in court?+", asks the lawyer.

Especially since in 1976, the British George Harrison had been deemed responsible for having "unconsciously" plagiarized "He's so Fine" of the group Chiffons for his solo title "My Sweet Lord."

In his memoir, the former Beatles wrote that he later suffered from "paranoia about songwriting".

This week, Ed Sheeran hinted that he could leave the stage if ordered to pay damages for plagiarism.

Other composers reportedly told him "you have to win for us", adding, a little exasperated in court, that if Townsend's heirs win he will be "finished" with the music.

"I find it really insulting to work all my life and to have someone denigrate him by saying I stole," he said.

© 2023 AFP