It’s hard to believe that the MP3 player, a technology that barely existed ten years ago, is now ubiquitous — most obviously in the shape of the iPod. Britain is cottoning on fast to the sheer indulgence of enjoying digital music on the move: the industry analyst Jupiter Research says that more than one in ten British homes owns at least one portable MP3 player, and expects this figure to double by the end of this year. So, what’s all the fuss about? Well, once you’ve converted your CD collection into MP3 digital computer files, or signed up to the domestic broadband explosion that makes downloading a doddle, you have unprecedented flexibility. You can allot 100 tracks to one bespoke compilation, choose the audio quality you prefer and send music wirelessly round the house. To join the podcasting revolution, MP3 is how you’ll listen.

The great joy of an MP3 player — shorthand for machines that often play other compressed digital formats, as well as MP3 — is the newly realised dream of toting a whole clutch of albums on one eminently pocketable gadget. You simply never know whether you’ll feel like humming along with Bob Marley or sighing your way home from work with Antony and the Johnsons, and it’s so 21st-century to have the choice.

Best of all, the collapsing price of memory makes music on the move ever more affordable. Mintel research shows that the average price paid for a portable music player of any type is, astonishingly, only £35. Of course, the best MP3 players cost £200 or more, but you can pick up a surprisingly potent bargain for much less, if you sidestep the no-name brands. Ministry of Sound’s MOS MP020 is a credible 128MB MP3 player, if limited in its two- or three-album capacity, and costs a mere £40.

Despite the undoubted benefits of MP3 machines, and oodles of hype, CD players still account for roughly two-thirds of the portable audio market. Rock-bottom prices are a factor, but many music fans clearly prefer the richer audio quality of uncompressed CDs, while technophobes are deterred by having to faff around with a computer to gain the benefit of compressed music formats.

Though it is true that even a modest CD player will paddle the pants off a good MP3 player in sheer sonic terms, this is usually because of the degree to which the MP3 has been compressed. The trade-off for compressing audio files — which inevitably strips texture out of the music — is the convenience of storing many albums on a player. So, before loading your machine, decide how hard you want your Coldplay squeezed. When memory was pricier, you would have compressed files until Mr Martin’s voice went decidedly squeaky, at 128kbps. Now that MP3 players offer gigabytes of memory, you can let him sing more naturally, at 192kbps.

The three crucial questions are:

1 Which family? MP3 players belong to one of two families. Those housing a laptop hard drive are often referred to as “jukeboxes”, because they offer storage running into gigabytes — enough to store thousands of tracks, in many cases. They also tend to be more expensive and bulky.

“Flash memory” players are driven by a solid-state chip, which means they can be small and light, but typically tote less than a gigabyte of storage. Flash MP3 players have evolved into bewildering styles, from swish-looking pendants to fully waterproof models for swimmers. It is these smaller flash players that are setting our credit cards twitching, says Nate Elliott of Jupiter Research, a trend spurred on by Apple’s Shuffle, the first flash-based iPod. The Shuffle delivers a gigabyte of capacity for less than £100, though it eschews even a basic screen.

The emergence of so-called “invisible” flash players, Elliott says, has fuelled the MP3 boom — because they are now “so small you can go out without even feeling them”. How rock’n’roll is that?

2 Convert music or buy? It’s true that you will have to tinker briefly with a computer to enjoy the fruits of any MP3 player, but it’s a relatively painless process, even with a basic PC. A key factor when buying an MP3 player is the software supplied for managing music, because this varies in calibre and affects your experience at the keyboard. You need suffer only once per album, whether you decide to rip (transfer) tracks from your existing CDs into compressed files or download music from the internet, paid-for or otherwise.

Each of these routes usually steers you towards deciding which file format to favour, the most popular being Microsoft’s WMA, Apple’s AAC, Sony’s Atrac3 and of course, MP3, which may be less efficient than newer formats, but is the most versatile for converting music from a CD collection (see Doors, July 17, at tinyurl.com/ 7b5ek, for how to do that).

All portable players now accept MP3 files, though some play only a specific type of paid-for music download. So, if you intend to cough up for downloads, this could prove a deal-breaker. Most famously, the iPod comes with iTunes but it ties you into buying future legit downloads from Apple. Another drawback of iPods is that backing up your own tracks from the player to a computer will require a third-party utility such as PodUtil (www.kennettnet.co.uk).

3 How many features? In addition to the size-versus-price conundrum when buying a music player, weigh up the relative importance of extra features — such as an FM radio or a voice-record function — alongside ease of use. Ease includes screen size, particularly for flash players, and, most important, how readily you can scroll through the index of tracks.

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