When Sony introduced the personal stereo more than 20 years ago, it revolutionized portable entertainment because it enabled music lovers to listen to their favourite tunes on cassettes anywhere, at any time, without bothering anyone else. Unless, of course, you were listening to George Carlin or Bill Cosby, in which case your laughter bothered - not to mention concerned - your fellow subway riders. Other manufacturers followed, and the original portable tape player inevitably led to the portable CD player, almost as small as a CD itself.

There are a lot of options out there, so you may want to buy online, rather than run from store to store comparing prices and styles. Try Battery Plus, Can Shop, Future Shop, Radio Shack and Sony Canada. These sites will not only deliver to your door, they will give you a good idea of what's available and what you can expect to pay.

Isn't that shocking?

As compact discs have taken over the music world, the portable CD player has become the most popular of the portable music players out there. Like the cassette tape players that preceded them, the main focus for manufacturers today is shock protection. You don't want the song to "drop out" because somebody bumped into you on the bus or because you were bouncing up and down while jogging. Discs skip because of vertical shocks to the disc as it rotates, and horizontal or rotating direction shocks. Horizontal shock protection is important because most people carry their disc players on a strap or in a bag, so the player is usually vertical when being used. So, even though you may be bouncing up and down, the player is being bounced from side to side.

That's why, for the newest portable CD players on the market, "the primary features will be better shock protection so you can run and skip," according to Michael Givens, senior product buyer at Bay Bloor Radio. Givens advises that if you are shopping for a portable CD player, go for one that offers the best shock protection you can find. Shock protection is measured in how many seconds the CD will play without skipping after it's been shaken up. The best is typically 40 seconds, which means you can shake up your player for as long as 40 seconds and it won't skip. But 41 seconds and you're in trouble. So before you buy, shake, rattle and roll your player while listening, to make sure the sound is not skipping or cutting out.

The new anti-shock technology essentially records music into memory, and then plays it back when "shocked." Ideally, you shouldn't even notice the skip. Once again, find out what the shock protection is, and go as close to the 40 second range as you can find. An added bonus of new shock protection systems is that they can save battery power. Newer models provide as many as 40 hours of use with 2 AA batteries, but also make sure your player has an AC adaptor, so you can plug it in the wall to save batteries when you're not on the road.

CD players plus

Of course, it's not just how good it plays, but also how good it looks. The main focus on the newer portable players, beyond shock protection, is size and shape. "Most of them are rounder, a little smaller, and some are with radios...and their designs are really neat looking," said Givens. With metallics, neon colours, vinyl and more, CD players are almost a fashion accessory. After all, you do wear it, right? And until now, CD players only played CDs, but more and more they're also offering AM/FM radios. You won't need the radio if you listen primarily while you're riding the subway, because you can't pick up most signals underground anyway. If you listen mostly outdoors, maybe a built-in radio is a good idea.

Today, there are dozens of portable CD players on the market, and choosing the one that's right for you can be a challenge. Other features to look for include programmability, which allows you to program your music to play songs in any order and to repeat your favorite tune if you want. Sports models should be a bit more rugged and provide splash protection, though that doesn't mean you can go swimming with it. And many CD players come with car accessory kits that allow you to play CDs through your car stereo by inserting what looks like a cassette into your car's cassette deck.

Glossary

Automatic volume limiter limits the "peaks" in the sound to protect your ears from sudden loudness, though you should avoid blasting the sound into your head at high volume anyway, because that can cause ear damage.

Remote control allows you to change tracks or songs if your player is in your bag and out of reach.

Resume feature starts a song right from where you had been when you stopped playing the CD.

Quirks

Take-it-with-you sound has grown exponentially, and now there's something called MP3 - music you can download onto your computer and transfer to a CD using a CD burner. For a quick primer on the future, check http://www.nomadworld.com/.