Jan Erik Kongshaug, a recording engineer who helped sculpt the rich and quietly splendorous sound of ECM Records, an influential label that has produced timeless jazz and contemporary classical recordings, died on Nov. 5 in Oslo . He was 75 .

His son Espen said the cause was a chronic lung ailment.

Mr. Kongshaug’s wide-ranging career included work with some of Norway’s best-known pop musicians. A guitarist since childhood, he also recorded two jazz albums of his own.

But his most lasting contributions came with ECM, where he engineered or mastered hundreds of albums from 1970 until the end of his life. Though he played a more inconspicuous role than Manfred Eicher, the label’s renowned founder and main producer, Mr. Kongshaug was arguably just as crucial to defining the famous “ECM sound,” which relied on precision and fidelity and used heavy helpings of reverb to create a feeling of both magnitude and intimacy .

“We had an influence on each other,” Mr. Eicher recalled in a phone interview. “He was not an experienced engineer at the beginning; I was not an experienced producer. We learned to capture sound together, to shape sound together.”