Music “is to the soul what the water bath is to the body,” wrote author and physician Oliver Wendell Holmes Sr. While Holmes’ observation might be true, music making, like bathing, does not necessarily merit an audience. The new Yamaha Silent Series (www.yamaha.com) is ideal for those occasions when you want, or need, to keep your songs to yourself. You play the instruments as you would any others, but they deliver sound only through an amplifier or headphones. The company’s silent string instruments—violin, viola, cello, and bass—are designed with a studio-quality onboard pre-amp instead of an amplification cavity. The instruments, which range in price from $845 to $4,000, have an auxiliary input that allows you to play along with a CD, an MP3 player, or another musician. Yamaha also offers silent trumpets, trombones, French horns, tubas, euphoniums, and flügelhorns.