Still Sounds Like Rock and Roll to Me

New earphones cause listener fatigue

(RxWiki News) Listener fatigue involves the discomfort and pain felt by some people while using the new type earphones and hearing aids. Instead of suggesting giving up iPod usage, which isn't going to happen, engineers found a  solution for listener fatigue: a new earphone.

Researchers from Colorado realized this listener fatigue did not respond to different audio mixes because the problem wasn't with the electronics.  The problem was in the earphones.  They were completely blocking the ear canal causing more sound pressure in the ear.

"New earphones reduce pressure in the ears."

Stephen Ambrose, an audio engineer, representative of Asius Technologies of Longmont, Colorado and old time rock and roller , describes how sealing a speaker in the ear canal dramatically boosts sound pressures and shaking in the eardrum. The researchers believe acoustic reflex, with its repeated use of tiny muscles may be the cause of listener fatigue.

Ambrose recommends a modified ear-tip which can help lessen or eliminate that effect. 

His group tried for years to lessen volume but still experienced audio fatigue. This was even at the lowest audio levels possible on stage remarked Ambrose, who has been leading the development of in-ear monitors for more than 35 years.

To counter the shaking, Ambrose and his colleagues at Asius developed a way to use a membrane outside the ear drum to take the pounding.

This "sacrificial membrane" disrupts the pressure, protects the ear drum and prevents triggering of the acoustic reflex, ultimately leading to lower, safer listening volumes.

Asius also developed an advanced corrective device called an Ambrose Diaphonic Ear Lens (ADELTM). The ADELTM is a tiny ear-sealing balloon. It uses a new technology called an Asius Diaphonic Pump to inflate it.

The Study

  •  Physical and computational models show that sound waves entering a sealed ear canal potentially produce dramatic boost in sound pressure levels
  • This boosts triggers the acoustic reflex, which is a defense mechanism the ear uses to dampen sound energy by as much as 50 decibels
  • Acoustic reflex doesn't, however, protect the eardrum from shaking
Review Date: 
May 13, 2011
Sound Safety