Hearing experts are concerned that the prevalence of digital music players may cause hearing problems in the future.

A report on The Scotsman warns music player owners, particularly iPod users, to turn their music down. The concerns stem from the way technology has marched on since the iPod debuted on the market. It offers a huge hard drive that is capable of carrying the very widest song selection, and also has a longer battery life than preceeding generation personal stereos such as the Walkman or CD players.

Pump up the volume, pump up the volume, pump up the volume - don't

"Audiologists believe tens of thousands of young people are causing serious damage to themselves, and are likely to suffer tinnitus and loss of hearing in later life. The experts say MP3 players should be designed to prevent people playing music above 90db, about two-thirds of the maximum volume of a typical device," the report warns.

Apple's device easily exceeds that volume limit - in fact a French law (emulated by Apple across Europe) requires that the computer company cap the iPods volume, but even the capped maximum still exceeds expert recommendations, at 100db.

The experts also warn people that they should only listen to their music player for a maximum one hour per day.

On the buses - ringing the decibels

Lisa McDonald, RNID campaigns officer, reportedly said: "Most people are listening to their iPods on public transport to drown out the noise of traffic, but to do this they turn them up to quite dangerous levels.

"For example the noise on the London tube is about 90db which is already loud enough to cause damage with a long period of exposure.

"Because music is enjoyable people are much more willing to tolerate those levels of noise for much longer."

Such concerns emerge as some pundits begin to speculate that the iPod is about to lose its 'cool' factor. With the US president attracting global publicity for his iPod's playlist, "what can Apple do to keep iPod chic and cutting-edge?"

The mortality of cool

The New York Times argues that Apple's marketing, both official and the viral effect of emerging iPod 'clubs', help keep the company ahead, but states: "Apple must continue to innovate to stay cool".

It's a challenge as the, "consumer electronics industry is ever-changing". It suggests a range of strategies Apple may explore to maintain its lead: Internet connectivity; mobile phone features, integration within other devices.

Apple products have achieved, "near-cult status partly because they cultivate an image as the electronics toys of the anti-establishment set," the report explains.

Competitors have a long way to travel. A reader's letter in Newsday sums up today's mood: "I have not bought a CD since getting my iPod, as I don't own any CD players anymore. Whenever I happen to get a CD, I automatically transfer it onto my iPod, then store it in my closet," the reader writes, warning of mass change in music consumption behaviours.

"Are iPods really the future of music? Only time will tell us for sure, but for me they are. In fact, I am listening to mine right now," the reader writes.