Albums are getting louder and the sound quality is suffering. Audiophiles and engineers despair of the trend, but who is driving it?

"I can't stand the sound of today's CDs," says Roland Stauber, a 39-year-old music lover who works in the automotive industry. "They sound harsh and loud. I hardly buy new releases any more."

Music nostalgia is nothing new, but this is different. There are solid technical reasons why CDs mastered today sound inferior to those made 15 years ago. The engineers who make the "master" - the mix from which the CD is pressed - are under irresistible pressure to compromise sound quality.

Tim Young masters albums at the Metropolis Studios in London. He has impeccable credentials, having worked with bands from the Clash and the Smiths back in the 1970s to Madonna, Iron Maiden and the Sugababes today. "Everyone's chasing immediate impact," he explains. "What happens is all the loud parts of the album have to be as loud as the opening track. So you get a fatiguing effect. There's no light and shade in it."

Young has first-hand experience of the "loudness wars", where studios compete to make ever louder CDs. "When CDs emerged as a format in the mid-80s, there wasn't a great deal you could do to make them louder. In the first half of the 1990s, various [electronics] boxes started to appear that meant you could get more apparent loudness. Mastering engineers, initially in America, started using these to make CDs louder. The impact travelled across the Atlantic," he says.

Damaged music

"In 1992 I did an album for a British heavy metal band. I got a panic-stricken message from their A&R man in America, saying 'We're really worried, the new album, it's not as loud as Aerosmith' or something. That was the start of it."

Of course, the mastering engineer has no control over how loud a CD gets played. But this is about the volume of the low-level signal encoded on the CD. Artists and record companies hope that louder music will stand out, but in practice the listener may just turn it down. Unfortunately, the techniques used to maximise the volume are damaging the music itself.

Steve Hoffman specialises in remastering classic rock albums, and he's a vocal opponent of the loudness wars. Asked to comment on recent releases, one from Lily Allen and the other from the Arctic Monkeys, he says: "Everything is loud, everything is bright, there's no subtlety in it at all, it's a sound that one would tire of fairly quickly."

Why does it sound bad? "A lot of signal processing is in the mastering stage, the type of processing that was almost impossible in the old days of analogue," says Hoffman. "Now you have digital workstations which mercilessly zap all the dynamics out of music. The other problem is overuse of equalisation (EQ). Equalisation done digitally is very harsh, and most mastering engineers tend to overuse it. You just crank up the EQ and then you compress it digitally so everything sounds like a machine gun, and then it all sounds really loud.

"Unfortunately, once the dynamics are shaved off music, it's impossible to get them back," says Hoffman. "It doesn't matter what volume you're playing at. When everything is loud, it doesn't sound loud any more. The only way that something can sound loud is if there's something quiet that precedes it, or else there's no frame of reference."

Jason Howse is a sound engineer who has worked with artists including Diva, Faceless and A Guy Called Gerald. Referring to dance music, he said: "You basically want the record as loud as you can possibly get it, because it's going to be played in an environment where level is everything." But why not use the volume control to avoid the loss of dynamic range? "That would be the thing to do," he answered, "but it's just what's demanded from record companies, not from the listener, but from record companies and artists."

Mastering engineers have little choice. "One of the myths that I'd like to eradicate is that this is all down to mastering engineers going crazy with their controls," says Young. "It's not. It's the artists and the producers who demand it.

"I had a famous 60s singer who's making a comeback this year. I'd mastered his album and I said, 'What do you think of it?' He said, 'It's great, but it's not as loud as the new Paul Simon. You've got to make it louder'."

Hitting the wall

How much does it matter? To a small but vociferous minority it matters a lot. Internet forums buzz with discussions about which older CD or LP release has the best sound as fans seek out the music of their youth.

"There's nothing wrong with distorted over-limited CDs per se," says Graham Sutton, a musician with Bark Psychosis and a sound engineer. "It's all aesthetics, after all. But what might suit Whitehouse or Merzbow might not be right for Norah Jones. It's now at the point where CDs cannot get any louder, just more distorted.

"The brick wall has been reached. I wonder how long it will be before the record companies re-re-release their back catalogue, re-re-mastered for additional dynamic range?"

· Compromised CDs

Lily Allen

Alright, Still (Regal, 2006)

This bouncy pop might sound better if it were not mastered for loudness at the expense of dynamic range.

Iggy Pop and the Stooges

Raw Power (Columbia, 1997)

Remixed by Pop in 1997, this remains among "the loudest CDs ever made".

Red Hot Chili Peppers

Californication (Warner, 1999)

Criticised for excessive compression and distortion. Subject of an online petition calling for a reissue.

Oasis

(What's the Story) Morning Glory (Creation, 1995)

Exceptionally loud album that forced others to compete in volume.

Rush

Vapor Trails (Warner, 2002)

"I can't get into this album at all, it lacks clarity, the songs sound the same," says one user review on Amazon. The overloud mastering may be to blame for this perception.

Paul Simon

Surprise (Warner, 2006)

Even long-established folk stars are competing in the loudness wars, to the detriment of the sound quality.

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