The game has changed – forever.

It’s no longer about sounding great on CD, it’s no longer about sounding great on the radio.

It’s about sounding great on Spotify, and this is fantastic news for anyone who loves great-sounding music, because it means the so-called “Loudness Wars” are about to become an irrelevant footnote in history.

If you live outside Europe, you may not be familiar with Spotify yet, but trust me – you will be.

Spotify enables you to stream almost any music you like to your computer or mobile device, in return for simply listening to a few ads, or for a modest monthly subscription fee. (Required for the mobile version.)

The interface is great – slick, professional and easy-to-use. The music sounds good – better than any mp3 thanks to the use of the Ogg Vorbis codec – and is available in even higher quality for subscribers. The catalogue is huge, and growing every day, and mobile users can even listen offline.

But what does this have to do with the Loudness Wars ?

The answer is - Spotify uses “Volume Normalisation” by default.

It adjusts the playback level of all songs so you don’t have to keep adjusting your volume control.

Which means that a genuine pop classic like “Billy Jean” will play at the same volume as the flat, fuzzy distorted mess that is Cheryl Cole’s new single.

And that anything off Kasabian’s latest album will play at the same volume as anything by Black Grape.

Or that “In Bloom” from Nirvana’s masterpiece “Nevermind” will play back at a similar level to U2′s recent Loudness-War-casualty “Vertigo”.

Guess which ones sound better ? The modern, brickwalled, crushed-to-death clipping victims, or the lower-level, more dynamic, open, punchy, older stuff ?

You guessed it. To take that last example, Nirvana wins – by a mile. The kick kicks, the guitars bite, the whole thing rocks. Vertigo is a limp, mushy lump by comparison.

Don’t believe me ? Try it yourself ! Fire up Spotify and pop those two into a playlist. If you don’t have Spotify, just line them up in any audio editor, and turn the U2 version down by 5dB. Or compare any of those tracks, making sure you use the TT Dynamic range meter to level-match them first.

Listen to the kick drums, the snares, the guitars, the bass.

(And while you’re listening, pause for a moment to think – have you ever heard anyone complain that “Nevermind” was too quiet ?!)

QED.

Every track has it’s playback volume adjusted according to “ReplayGain” values which give a decent estimate of a song’s apparent volume and therefore how dynamic it is. Very dynamic material will be compressed somewhat to boost it’s average level, but almost all recent, heavily compressed and high-level material will simply be turned down a little.

Now some of you will be saying – “ReplayGain ? I’ve heard all of this before – so what’s the big deal about Spotify ?”

Easy. Spotify is going to take over the world.

Think about it – the first evening I paid my £10 subscription and installed Spotify on my iPod, I downloaded over 200 songs. 100% legally. A week later it was over a thousand. Some are old favourites, some are new experiments. None of them are things I would have bought on CD or even mp3. And as long as I pay my subscription, I can listen to them wherever and whenever I want.

Pretty soon, this is how everyone will listen to music. (Except it’ll be with a lossless codec ) Eventually nobody will own any hard copies at all, it’ll all just sit in the cloud waiting for them to call on it.

More importantly, Spotify is where everyone will listen to new music first.

And all those people listening to music for the fist time on Spotify will have volume normalisation enabled by default.

Meaning if you want your music to sound great and leap out of the speakers at you, it doesn’t need massive level, it needs great dynamics.

Game Over.

PS. Metallica aren’t on Spotify yet, but when they are, do you think they’ll still be impressed by the 2dB-dynamic-range sound of “Death Magnetic” ?

Ian Shepherd is a mastering engineer and producer at Sound Recording Technology. He writes the respected Mastering Media blog, and runs the Production Advice website.