CHAPTER 3 How Digital Music Works 41 (or grandparents!) bought at the local record shops. The records were played back on phonographs equipped with their own needles; special circuitry trans- lated the needle's vibrations into electronic signals that could be amplified and sent through one or more speakers or headphones. That's how analog recording works, and it works just fine--as far as it goes. The big problem with analog is that, no matter how thin the needle or involved the process, it can't exactly reproduce the original music. The wave- form associated with live music is rather complex and has a large dynamic range--the difference between the loudest and softest passages. This means that even the best analog recording equipment can't make an exact reproduc- tion of the original. In addition, analog recording introduces extraneous noise and distortion into the process--especially when copies are made. This means that playback is often plagued by the annoying hiss and pops produced when the needle passes over the vinyl groove. Finally, analog recordings can only be stored physically. You can't transfer an analog recording to a computer for storage without first converting that ana- log recording into a digital file. That's because all computer data is digital; it's 3