In the early 1930s portamento, a technique that had long been integral to the art of violin playing, began to fall into disfavor. This article contends that the decline in portamento was closely tied to the rise of a technology that was intended to preserve—not change—musical performance: sound recording. The decline of portamento may be understood in part as a “phonograph effect,” a response to the unique qualities and demands of recording technology. While portamento may create a sense of impulsiveness or spontaneity in concert, robust sliding (which was common in the early twentieth century) may sound calculated or contrived when heard repeatedly on record. Moreover, violinists found that early microphones tended to exaggerate portamento to an unacceptable degree. Thus, what had been one of the primary expressive vehicles in violin playing became a subtle and selectively applied ornament, in strong measure in response to a technology that could transform sound and make performances permanent.