Short article from Popular Science
"Normal earbuds have just one, sometimes two speakers on each side. But those micromachines must handle a wide range of sounds, from Mariah Carey’s high register to Barry White’s silky bass, so they struggle to faithfully reproduce all the right acoustic details. The $2,200 Ultimate Ears Live headphones are different. Each in-ear unit contains eight speakers, and each of those is tuned to a specific part of the audio spectrum. Built for professional musicians who play massive stages, the buds produce a rich, true depiction of the tunes. This is what makes them sing. "
https://www.popsci.com/ultimate-ears-live-headphones?CMPID=ene090418
"Normal earbuds have just one, sometimes two speakers on each side. But those micromachines must handle a wide range of sounds, from Mariah Carey’s high register to Barry White’s silky bass, so they struggle to faithfully reproduce all the right acoustic details. The $2,200 Ultimate Ears Live headphones are different. Each in-ear unit contains eight speakers, and each of those is tuned to a specific part of the audio spectrum. Built for professional musicians who play massive stages, the buds produce a rich, true depiction of the tunes. This is what makes them sing. "
https://www.popsci.com/ultimate-ears-live-headphones?CMPID=ene090418