C 难度：★★★★

　　Whether or not you’re a guitarist, you’ve probably at least once found yourself wondering why a musician would play an old guitar that’s falling apart when they could easily afford 100 new ones. Aside from aesthetics (审美学) and familiarity—every guitar is different, and players grow attached to them as if they are family members—there’s another reason: instruments sound better as the wood they’re made from ages.

　　What happens when wood ages? All wood gradually loses hemicellulose (半纤维素) over a long period of time. As this happens, the wood loses some weight, but remains just as firm, allowing it to continue to support the weight of strings. With less mass to have to vibrate (振动), the guitar’s wood vibrates more freely, making the instrument louder. Similarly, lignin (木质素) decreases as wood is exposed to sunlight. Most notably, this results in usually white wood taking on a yellow or orange color that tends to be considered more aesthetically pleasing. Of course, a decrease in lignin means a change in the wood’s physical structure as well, meaning that it improves the sound effects of aging.

　　Guitar manufacturers have long been selling guitars with aging toners to make their instruments look like they’ve seen more years than they really have, and these only affect a guitar’s aesthetics. More recently, however, manufacturers have begun to treat wood with a process called baking. Wood used in guitar building is usually dried to a moisture (水分) level of about 6-10%. Usually, that is all that’s done, but some wood is subsequently “cooked” at even higher temperatures in an oxygen-controlled environment until the wood’s moisture level reaches zero percent.

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