Who guitarist Pete Townshend is warning iPod users they may face hearing loss if they pump up the volume on the devices.

Townshend, 60, said his hearing was irreversibly damaged from using studio headphones, and he now takes 36-hour breaks between recording sessions. The band was known for loud performances.

"Hearing loss is a terrible thing because it cannot be repaired," Townshend said on his website. "If you use an iPod or anything like it, or your child uses one, you may be OK. (...) But my intuition tells me there is terrible trouble ahead."

Listening to loud music through headphones and earbuds for an extended period of time can cause permanent hearing loss. Everyone is at risk, said Janice Mayes, an audiologist in Vancouver.

"In the past, people didn't have these devices and people weren't wearing them as much," said Mayes. "Now people tend to be wearing them for longer and longer periods during the day, so it's definitely a concern."

People should never turn the volume up past halfway and never listen more than eight hours at a time, Mayes advised.

The portable devices themselves aren't inherently harmful to hearing, but blasting music so surrounding noise can't be heard should be avoided, agreed Paul Kileny, director of audiology at the University of Michigan.

Kileny said he and other doctors are seeing more young people with noise-induced hearing loss compared to when people listened to Walkmans for shorter periods of time 15 years ago.

He recommended manufacturers add controls to the devices to encourage people to keep the volume at a reasonable level. These could include a warning light that comes on when a certain decibel level is exceeded, he said.