New product rollouts and the growing penetration of smart phones is prompting new sponsorship activity on behalf of headphone manufacturers.

Much of that activity is driven by small, upstart companies that market products targeted at athletes and other niche audiences.

Recent deals include Skullcandy, Inc.’s presenting sponsorship of the Identity electronic music tour; Polk Audio and the Under Armour Baltimore Running Festival; and Verto Medical Solutions, LLC’s sponsorship of the ING New York City Marathon on behalf of its Yurbuds headphones.

In addition, House of Marley Ventures, Inc. served as the official headphone of the Dec. 9 Z100 Jingle Ball New York and Dec. 3 KIIS-FM Jingle Ball Los Angeles, while h20 Audio earlier this year partnered with USA Water Polo.

The new deals come amid a backdrop of rising sales. Sales of headphones in the U.S. nearly doubled in the year ended August 2011 to roughly $2 billion, according to NPD Group, a market research firm.

Like other products in the consumer electronics category, headphone manufacturers largely use sponsorship as a platform to demonstrate their products.

For example, House of Marley leveraged the Los Angeles Jingle Ball by showcasing headphones out of a customized 1958 VW van. Attendees also could record a video singing their own version of a classic Bob Marley song.

In addition to music fans, headphone manufacturers are increasingly using sponsorship to reach runners, swimmers and other athletes in need of activity-specific products. Case in point: h20 partnered with USA Water Polo to promote its waterproof headphones to swimmers, while Yurbuds and Polk Audio partnered with marathons to tout running-specific headgear to runners.

For example, Yurbuds sponsored the New York City Marathon to promote its headphones that fit outside the ear and let runners hear ambient noise, said Ann Crandall, executive vice president of business development and marketing strategy with New York Road Runners, which owns the marathon.  

Yurbuds also markets products under the Ironman name, she added.

Another key trend: The growing number of rap artists launching headphone brands. Those include Beats by Dr. Dre; Soul by Ludacris and 50 Cent’s Sync by 50.

In addition, Skullcandy has teamed with rapper Jay-Z to develop a line of headphones marketed under the Roc Nation Aviator brand.