New York’s highest court ruled Tuesday that common law protects the rights of a record company to all sound recordings made before the 1972 federal copyright law in a decision that could affect old hits from Bach to the Beatles.

The state ruling, critical to a federal case, clarifies the federal copyright law for pre-1972 recordings that was challenged by one of a growing number of discount record companies restoring and marketing old performances. The federal law provides nationwide copyright protection only to recordings since 1972, but a provision that called for state and common law to apply before that enactment date hadn’t been tested. A federal court turned the question over to the state Court of Appeals as part of a copyright infringement lawsuit.

In this case, Naxos of America Incorporated restored and marketed 1930s classical records made in England by another company, The Gramaphone Company Limited, after the 50-year British copyright had expired. The New York court ruled, however, that state common law still protected pre-1972 recordings.

“I hope the companies who have been inclined to copy older classical recordings realize the New York court has spoken definitively on this and end any unlicensed copying,” said the attorney for Capitol Records, Philip Allen Lacovara. He won the 7-0 state decision released Tuesday. “It does have enormous importance.”

He said the result is that artists, their estates, and others involved in recordings made before 1972 could collect royalties in America for their performances.

Naxos’s attorney, Maxim Waldbaum, said he will appeal the decision, which he called flawed.

“There’s a certain insanity to it,” he said. He said the court, for the first time, said copyright infringement can be proven even if there is no bad-faith effort or harm proven.

He said the law restricts firms like Naxos to recover lost works to be reintroduced to music lovers. “There will be works of music lost forever now,”he said.

The New York court decision applies to all recordings marketed in New York even if no other state or foreign law or common law was still in force, according to the decision.

Currently, the recordings at issue are mostly made abroad featuring classical performances, dramatic readings, and oral histories that some companies now are copying and marketing without paying royalties. But much of the court argument also centered on British Invasion rock and pop groups from the 1960s. Many will soon lose copyright protection under British law and wouldn’t be protected by the 1972 American copyright law without yesterday’s state court decision, Mr. Lacovara said.

Yesterday’s decision involved the 1930s classical performances originally recorded on shellac disks in England by Gramaphone, now known as EMI Records Limited. In 1996, EMI licensed exclusive rights to market the original recordings as compact discs and other products in America to Capitol Records.

But in 1996, Naxos, another music recording company, began to sell its own restorations of the recordings, competing with Capitol’s compact disc and other recordings of the same performances. Capitol sued Naxos for copyright infringement based on the 1972 law.

A federal court dismissed Capitol’s suit saying the federal law didn’t apply to pre-1972 recordings and Britain’s copyrights expired 50 years after the records were made. The federal court said Capitol had no common-law right, either, under New York state law.

Capitol appealed the common-law ruling to the New York Court of Appeals to determine whether Naxos is entitled to defeat Capitol’s claims for copyright infringement under New York common law. The federal court will rule on the lawsuit using the state court’s decision.

The recordings at issue included the Yehudi Menuhin 1932 performance of Edward Elgar’s “Violin Concerto in B minor, Opus 61, “Pablo Casals’ performances of J.S. Bach’s cello suites recorded between 1936 and 1939, Edwin Fischer’s performances of Bach’s “The Well Tempered Clavier, Book I,” recorded in 1933 and 1934, and “The Well Tempered Clavier, Book II” recorded between 1935 and 1936.

“The artists’ contracts specified that Gramophone would have absolute, worldwide rights to the performances,” according to the decision written by Judge Victoria Graffeo.

“The answer to this question will have significant ramifications for the music recording industry, as well as these litigants,” the court stated.

Naxos bills itself as “the world’s leading classical music label” with more than 2,500 recordings of performances at low prices. A small segment are restored recordings.