Able Planet: Constructive Distortion
Hearing loss ultimately is about hair loss: the death of the tiny hairs that line the cochlea of the inner ear. Sound waves bend the hairs and thus the cells from which they sprout, and that motion creates electrical signals that auditory nerves pass on to the brain, which interprets them as sound.
HEARING LOSS ULTIMATELY IS ABOUT hair loss: the death of the tiny hairs that line the cochlea of the inner ear. Sound waves bend the hairs and thus the cells from which they sprout, and that motion creates electrical signals that auditory nerves pass on to the brain, which interprets them as sound.
But if the sound pressure level (SPL) is too high, it can whip the hairs so far in one direction that they're damaged. In some cases, the damage can be severe enough that the hair cell dies. Once a hair cell is gone, it's gone forever.
Able Planet's Linx technology has been used in headphones, but the company is thinking bigger when it comes to enhancing audio.
The effect of that hair loss varies, but one common result is that certain sounds become difficult to pick out. For example, when listening to speech, high-frequency sounds such as the letters “S” and “H” might no longer be distinguishable.
The founders of Able Planet wanted to find out how to get those high-frequency sounds back. It was a quest born out of personal experience: all of them suffered hearing loss, one of them profound.
The Wheat Ridge, Colo.–based company developed techniques and technology—since branded as Linx Audio—that restores high-pitched sounds such as “Th” and “F.” The end result is that Able Planet essentially expanded the concept of hearing aids from a stand-alone product aimed at the hearing-impaired to a technology that could be embedded in headsets and loudspeakers intended for people who don't necessarily have hearing loss. For example, Linx's users include linguists and language labs because the technology preserves intonation and other nuances.
“Our target group is the audiophiles—people who love music and are spending $20,000 on speakers, cables, and home stereo systems—[as well as] gamers and people 55-plus,” says Kiva Allgood, Able Planet's vice president of marketing.
HARMONICS AS ASSETS
Over the past two years, Able Planet's Linx technology (www.ableplanet.com/linxtechnology.html) has built a buzz among reviewers and racked up recognition such as back-to-back Consumer Electronics Show (CES) awards. The difference that consumers and reviewers say they notice is due largely to a technique that Able Planet calls Harmonic Enrichment.
It's based on the fundamental concept of harmonics, where a sound can be spontaneously produced at multiple frequencies. For example, a tone at 500 Hz can produce harmonics at 1 kHz and 3 kHz. In the ear, the original, fundamental tone and its harmonics each whip different sets of hair cells.
The catch is that the ear doesn't distinguish between the original tones and its harmonics. Instead, the cochlea aggregates the electrical signals from each set of hair cells, so to the brain, they literally all sound the same.
Linx leverages that ability: If one set of hair cells is damaged or dead, there's a chance that other sets are still alive and well. There's also a chance that if one of the dead sets covers a particular fundamental tone, a set that can “hear” its harmonic is still functioning. So unless a person is completely deaf, Linx can create harmonics that the remaining hair cells pick up and interpret as the fundamental tone.