Is your device a phone? If so, its headphone jack was probably designed for, well, headphones. Plugging it directly into speakers will boost your volume,which can, in some cases, be enough to make low-quality MP3s sound really bad. But without an amp or digital-to-analog converter, you probably won’t be able to hear the differences between the 320 kbps MP3 and the uncompressed WAV file.
錯在 Mozart: Piano Concerto No. 17, K. 453 (II. Andante) 跟