Americans also have spent the last several years buying tablets, smartphones and TVs. Now, many are looking for ways to squeeze better sound from those gadgets.
"It stands to reason that people at some point want a better audio experience than the ear buds you get in the box," said Ben Arnold, NPD's director of industry analysis.
Indeed, Drew Smith, 21, began coveting better headphones when he got an iPhone 5 in August. Now, headphones are the only big present he's asking his parents for.
"Because of my smartphone, I listen to more music and ... I want a good set," said Smith, a cinema manager who lives in Paragoule, Ark.
Likewise, Adam Daniels, 23, a commercial banker from Sharonville, Ohio, decided to buy a Phillips sound bar for his parents for Christmas after they purchased a 50-inch TV.
"They have a great TV, but the audio on it is terrible," he said.
The trend this season is a continuation of an audio craze that started last year. That's when Beats by Dr. Dre, oversize headphones that come in different colors and run about $200 per pair, became the "it" holiday gift.
Beats doesn't give sales figures. But the company said it grew its share of the market for headphones over $99 from 71 percent last year to 78 percent this year.
Some competitors also have upped their sound game. This year, stores and analysts say Bowers Wilkins, Bose, Jawbone and JBL all are among those offering more products, colors and stylish designs.
"Audio has been really popular this holiday," said Josh Davis, manager of Abt Electronics, a large electronics store in Chicago. "Last year, it seemed like all anyone wanted was Beats ... But we're seeing good competition this year among other brands."
At the same time, prices have fallen for some audio gear. For instance, the average selling price for wireless speakers dropped 33 percent to $73 this year compared with last year, according to NPD. And Best Buy, Amazon and other stores have offered deep discounts on some audio gear.
Target, which says sales of headphones, wireless speakers and sound bars have "increased significantly" this year, offered deals on the day after Thanksgiving known as Black Friday. They included the Beats Solo HD Headphones for $119 from $179.99; Sony Bluetooth speakers for $49.99 from $89.99; and a JBL sound bar for $99.99 from $199.
The deals influenced Rob Patak, 29, to give headphones as gifts for his roommate and friend. Patak, a customer support manager at a software company in Washington, D.C., bought wireless speakers art Marshall's for $20. And when he saw Amazon was offering $50 off $100 Plantronics Backbeat Go headphones, he snapped up two pairs.
Price was also a consideration for Jeremy Sylestine, 34, a prosecutor in Austin, Texas. He had been searching for a sound bar for his 40-inch TV last year but couldn't find one for a good price. This year, though, he bought a Samsung sound bar for $184, which was $70 off the original price.
"It was the only thing that was on my list," Sylestine said, adding that he found "basically an unbeatable price."