The Insider: MP3s in the dock, make sure you get it right

MP3 players have revolutionised the way we listen to music on the move. Speaker docks aim to take the revolution a stage further – allowing you to put your MP3 player at the heart of your home music system and clear away that pile of dusty old CDs for good. There are lots of cheap portable speaker docks on the market, starting from less than £40, but they're unlikely to do justice to your music collection and for excellent audio quality, you should expect to pay more.

First check compatibility with your MP3 player. "Virtually all docks available on the high street are designed for use with Apple's ubiquitous iPod," says Matt Bath, technology editor at Which? "But don't despair if you have an alternative brand of MP3 player, it will usually still work, but instead of nestling neatly in the specially-designed dock you may need to connect it via a headphone jack."

It's worth checking whether your MP3 player fits, especially if it's not one of the latest generation. It should say on the packaging which players the speakers will work with, but beware that iPod-compatible gadgets often work with the Classic and Nano models, but not the Shuffle.

In Which?'s latest test, the highest-scoring model was the Bower & Wilkins Zeppelin. Which? gave it a test score of 71 per cent and found that the sound quality was impressive, with bass notes sounding rich and warm. It's got a distinctive design and is fully compatible with the latest Apple products, but the "wow factor" comes with a hefty price tag (it's £399) and it is heavy and bulky, so you'll need space to accommodate it.

At the other end of the table the XtremeMac Tango Digital X2, from £85, scored just 27 per cent and was given a Which? Don't Buy rating. This flat-sitting speaker dock certainly bucks the trend in terms of design, with the docked MP3 player sitting on top rather than in front of a speaker, but functionality is limited and sound quality is poor. Testers said that music sounded shrill and distortion was audible.

If you don't want to splash out on a speaker dock, then connect your MP3 player to a hi-fi system using a 3.5mm twin stereo phono cable, which costs around £5. The sound quality will be better, even with a modest hi-fi system.

Where to buy? Searching online will often turn up cheaper prices for speaker docks and other MP3 player accessories. You can check stockists and compare the latest prices using Which?'s price comparison service www.whichcompare.co.uk

What to look out for: Questions to ask yourself

Is it compatible with your player?

Don't assume a dock will work with all music players, especially if you have an older model or it's not an iPod. Check what it says on the packaging. USB or FireWire connection? The very latest MP3 players from Apple can dock and play music through FireWire-based speaker docks, but they won't charge up.

How good is the sound quality?

None of the speaker docks Which? has tested comes close to hi-fi quality, but the difference between a good and bad loudspeaker can be considerable. Music is likely to sound distorted on very cheap speakers.

How portable is it?

If you can't easily move it around the house, you may as well connect your player to your hi-fi instead. Models that can be powered by batteries are ideal if you want to listen to music in the park or garden.

What is the battery life?

On the models tested by Which?, battery life varied from five to 25 hours – which could make a big difference if you're on the move.

The Insider is written by Which?, the independent consumer champion. For more information go to www.which.co.uk/speakerdocks. To get three issues of Which? magazine for a special price of £3, call 01992 822800 and quote INADVICE.