When Pharrell Williams and Robin Thicke brought a lawsuit in August 2013 and demanded a judicial ruling that the monster hit “Blurred Lines” wasn’t a copyright infringement of Marvin Gaye‘s “Got to Give It Up,” most observers took a listen of both songs to compare.
But that’s not what a jury will do at a trial scheduled next month after a judge on Monday precluded Gaye’s sound recording from being introduced.

The “Blurred Lines” case has suddenly become a good lesson on the fact that songs embody multiple copyrights. There’s a copyright for the person or people who compose a song. There’s a copyright for the person or people who publish a sound recording. Well, most of the time.

In October, Williams and Thicke failed to win the case on summary judgment, and while that might have seemed to be a great setback for them at the time, there was another aspect to U.S. District Judge John Kronstadt’s opinion that got far less attention but could become one of the more precedent-setting features of this multimillion-dollar case. In his ruling, the judge looked to old standards under the 1909 Copyright Act and concluded that the Gaye family hadn’t sufficiently shown it made necessary deposits of the “Got to Give It Up” sound recording at the Copyright Office. As such, Gaye’s copyrights on the song were limited to the sheet music compositions.

In light of this development, Williams and Thicke brought a motion on the eve of trial to bar the sound recording from being played. In response, Gaye’s family argued that the composition is embodied in the sound recording, and the latter stood as good evidence that the composition was lifted by Williams and Thicke in “Blurred Lines.”

Judge Kronstadt is siding with Williams and Thicke on this one — leaving the Gaye family attorney Richard Busch quite astounded.

“Pharrell Williams and Robin Thicke started this lawsuit against the Gaye family, but then filed motions asking the court to prohibit the playing of Marvin Gaye’s song, which prevents the jury from comparing the songs,” says Busch. “We know of no similar case where this has occurred, and do not believe that a truly fair trial can take place if the jury cannot hear and compare both songs. We are currently exploring all of our options.”

In the past, Howard King, the attorney for Williams and Thicke, has suggested that jurors will still be able to analyze Gaye’s composition adequately by hearing it played on keyboard. What the jurors won’t hear without the “Got to Give It Up” sound recording being played to them are non-copyrighted elements like Gaye’s voice, percussive choices and backup vocals. King believes the judge made the right call.

“A truly fair trial requires only a comparison of the compositions, not the sound recording which is not owned by the Gayes,” says King. “Given the fact that the compositions have absolutely no substantial similarities, there is little chance the Gayes can prevail at trial or on any threatened appeal.”

Right now, the trial is scheduled to begin on Feb. 10.