"Can you hear me now?" is taking on new meaning.

If you've ever suspected that the popular earbud headphones -- which place the sound of music in the ears -- might have a deafening effect, you had it right. With the volume turned way up, even an hour a day of direct-to-the-eardrums sound could lead to hearing loss. Here's some good news: You can download free software that locks in a volume limit on your iPod.

Music addicts quickly discover that, unlike earmuff-style headphones, earbuds let them listen to tunes at a higher volume without anyone yelling, "Turn it down!" But whether the noise is hip-hop or Bach, overexposure can harm the ear's sensitive hearing mechanisms -- temporarily, if you're lucky, permanently, if not.

It's a good idea to limit both volume and the time spent wearing any headphones, but especially earbuds. Some experts suggest aiming for no more than a few hours a day of exposure to sounds higher than 90 decibels (about the sound of a vacuum cleaner or lawn mower). But to keep hearing sharp for years to come, noise researchers studying headsets recently recommended using them no more than an hour a day.