The Last Battle Of The Loudness War

Mastering engineer Bob Katz says the war has been won   14-Feb-14

This press release is just in:

Orlando, Florida: "The debilitating loudness war has finally been won," said mastering engineer Bob Katz on the eve of the Audio Engineering Society (AES) Convention in New York City. "The last battle will be over by mid-2014."

"I have just completed loudness measurements of iTunes Radio using iTunes version 11.1.1. Tunes Radio's audio levels are fully-regulated, using Apple's Sound Check™ algorithm. This is a very important development," Katz said.

During several hours' testing, Katz measured the output level of several stations, and concluded that each song's loudness averages -16.5 LUFS, within better than 2 dB, usually plus or minus 1.5 dB. The Apple release notes state that version 11.1.1 "improves stability", which he interprets as having solved some loudness regulation issues which were present in the previous iTunes release.

It is clear that music producers want their music to sound as good as possible on the nascent but already popular iTunes Radio platform, given the many listeners instantly available. This immediately opens an opportunity to curtail the loudness race within the next few months. Added Katz, "The way to turn the loudness race around right now, is for every producer and mastering engineer to ask their clients if they have heard iTunes Radio. When they respond in the affirmative, the engineer/producer tells them they need to turn down the level of their song(s) to the standard level or iTunes Radio will do it for them. He or she should also explain that overcompressed material sounds wimpy and small in comparison to more open material on iTunes Radio."

Katz suggests, "The engineer/producer should also tell their clients to turn on Sound Check in iTunes to hear their music exactly the way they will be broadcast on iTunes Radio. This makes all music played in iTunes, whether it be on IOS devices played while jogging, connected in the car, or on the desktop computer, perform consistently. It's a revolution in the making, with instant positive results."

Katz's discoveries show that current squashed and smashed pop releases are being attenuated more than 7 dB in order to make their loudness equal to that of more-conservatively mastered releases. In other words, true peak levels of current pop songs are as low as -7.8 dB below full scale! "There is so much available peak headroom now in iTunes Radio that anyone who wants to master their songs with more conservative levels and prefers higher peak-to-loudness ratios will produce music with immediate loudness and sound quality advantages, compared to what's being played out there now. The cream will soon rise to the top. The music will sound better, even a bit louder, and will attract more listeners. iTunes Radio is already so popular that it will end the loudness race by force majeure. This development is a great opportunity for producers to explain and demonstrate to their clients how to make their songs sound better on iTunes Radio and everywhere else."

Sound Check is on by default in iTunes Radio and cannot be turned off. However, currently, song files which are on the computer or the iDevice are not loudness-regulated by default, so consumers and musicians who listen to iTunes Radio will quickly discover that Radio sounds more consistent than their playlists, that they don't have to turn their volume controls up and down when listening to Radio. iTunes Radio also reveals that overcompressed songs sound worse, and not louder than their competition. Therefore, it is imperative for producers and engineers to educate clients to turn on Sound Check so they can hear what their songs will sound like on Radio, and for better listening. "Magazines, newspapers and other media outlets should encourage their readers to turn on Sound Check to make their devices conform with iTunes Radio," said Katz. "All it takes is a little educating and self-discovery."

"There will be still some skirmishes, but the main battle has just been won. Producers, engineers and musicians will ultimately discover this news themselves, but journalists and producers can hasten the close of the war, starting right now." To discuss this important event, Katz invites musicians, producers and engineers to join the free discussion forum at www.digido.com.

The discovery that iTunes Radio may be regulated with the Sound Check algorithm was made by engineer Robin Reumers of Galaxy Studios, Belgium, on September 20th. Reumers then began a discussion with fellow loudness researchers Thomas Lund of TC Electronic and Bob Katz of Digital Domain Mastering. Katz immediately made measurements and found some iTunes Radio Stations that were inconsistently regulated, and he suggested that iTunes Radio might not conform to Sound Check. However, the maintenance release of iTunes opened up a possibility, and on October 15th, Katz tested iTunes 11.1.1 and confirmed that Apple appears to have conquered the loudness inconsistencies. Reumers pointed out that this must mean that Sound Check metadata is being broadcast on iTunes Radio and that Apple had to tweak the receivers in order to properly react to the metadata. Apple does not normally comment on their technical data or procedures, leaving the task of confirming measurements to the audio community.

"I urge readers of this press release to enter into discussion on the forum at www.digido.com," said Katz. "Especially if you have any information on Apple's technical practices. The forum will serve as a central meeting place for producers and engineers who want to see the loudness war end as quickly as possible."

More information:

• www.digido.com