IF you don't have Kate Bush's Aerial album to hand, you better go and get a copy. Presuming you have it now, take a good look at the front cover artwork. It looks like a soundwave image - and that's because it is a soundwave image.

Someone, somewhere, possibly connected with Kate Bush, possible connected with her label, EMI, or even possibly with no connection to either, has started a story about how this soundwave is a visual representation of spoken, or sung words, over music.

A few people have already attempted to break the Bush code. So far, the leading suggestions are that the soundwave represents the words "We paint penguins pink". Others say they have conclusive proof that it says "Elvis is alive" (they back up this argument by mentioning that the first single from the album is about Elvis). However, there's also a growing number of people who believe it says "Wind and waves of love" - which, to be fair, sounds the most Kate Bush-sounding.

Apparently the soundwave is there to baffle and perplex the many Kate Bush anoraks out there - the types who go in for a bit of fervent exegesis of all things uttered by La Bush. It is also understood that the true meaning of the soundwave will only become clear after listening closely to the album.

You may need a pen and a piece of paper for this next bit. To crack the code, you need a very high-resolution version of the cover, you then have to use Photoshop to adjust the contrast until you have a very distinct image of the waveform. Now you try and turn the finished image into sound, by using a special Windows program called "Bitmaps and Waves". This should give you a full audio file. Click to play the audiofile and you will hear what it is Kate Bush wants you to hear.

If you've got stuck along the way, you'd better check your volume envelope and position with respect to time (rhythm) of the recording and the not the actual oscillations being produced, this is because Bitmaps and Waves uses a Sine oscillator to generate sound files.

It will come as no surprise that some people have gone through the above process laboriously. It will also come as no surprise that in all likelihood there is no secret message to be played.

Simply because Kate Bush put a soundwave on the cover of her album doesn't mean that it signifies anything. It's all a bit like Linsday Anderson's classic If film. On its release, a lot of critics got very excited by the fact that the film switched between colour and black and white. All sorts of fevered arty theories were postulated as to the significance of the switch between colour and black and white at key moments. It was only much later when Anderson was asked about this specifically that he replied, rather dryly, that the film had gone over-budget and he couldn't afford any more colour so he had to shoot the latter part of the film in black and white.

We can safely take it that Kate Bush is simply having a laugh with her mysterious soundwave image. That's certainly what she's doing on the first single, King of the Mountain, which contains references to Elvis Presley and Rosebud. She's playing with the themes of disappearance and mystery because of her own so-called "mysterious disappearance" from the music world.

But there are still people out there who think that if you speed up the audio file of the image so that it takes three seconds to play instead of 30, you will hear something. Others think the key here is to turn the image on its side (great idea - now it looks like a soundwave on its side). There's even professional sound editors on the case - they argue that you can't decode the image back to sound because "it's not zoomed out enough". Some sound editors even believe that it doesn't represent speech at all - it could possibly be a few blasts on a saxophone.

Here's a mad idea, from way out on the left-field: Kate Bush used the image of a soundwave because she thought it looked nice.