Task: Question Generation
Input (English): The term "high fidelity" was coined in the 1920s by some manufacturers of radio receivers and phonographs to differentiate their better-sounding products claimed as providing "perfect" sound reproduction. The term began to be used by some audio engineers and consumers through the 1930s and 1940s. After 1949 a variety of improvements in recording and playback technologies, especially stereo recordings, which became widely available in 1958, gave a boost to the "hi-fi" classification of products, leading to sales of individual components for the home such as amplifiers, loudspeakers, phonographs, and tape players. High Fidelity and Audio were two magazines that hi-fi consumers and engineers could read for reviews of playback equipment and recordings.
Output (English): During what years did the term HiFi take off with engineers?