Of the estimated 36 million Americans who report some level of hearing loss, as many as 20 million have mild to moderate conditions, in which they struggle to pick out voices in cacophonous settings. Although the condition is common, treatment is limited. Custom-fitted hearing aids, which can be adjusted according to an individual's needs, cost as much as $3,000. Users can instead opt for cheaper, over-the-counter amplifiers, but those simply increase the volume of all ambient sounds and do little to help in conversation. To address the needs of this group, the Colorado company Able Planet reconfigured the noise-canceling circuitry from its headphone line and created the first over-the-counter device that isolates and amplifies voices.