Audio loudness/normalisation

[Gary Nattrass]

Originally Posted by Vincent Oliver

What would be the acceptable peak level for web video and DVD/BluRay discs. at the moment I am working to -6db

That is what I work to as well and it is -6dbfs (decibels full scale) which is a scaled level measurement as opposed to dblu which is an average loudness measurement normally dblufs-23.

People should note that levels and loudness are not the same thing as two mixes can have the same levels but may not have the same loudness.

dbfs is a level measurement that equates to digital full scale metering and the new dblufs reading is a relative loudness measurement for audio delivery.

So whilst your broadcast material may be lined up with 1khz tone at -18dbfs with a max peak level of -10dbfs (-20dbfs and -12dbfs for the USA) the loudness measurement for the whole programme content must be -23dblufs.

DVD and web content is different and you can put the levels where you wish but -6dbfs seems to be a good compromise for peak levels, loudness measurements tend not to apply as you are not trying to even out programme content to loud commercial breaks.

Of course good metering is essential if you are delivering for broadcast or critical applications and I personally have some old BBC type PPM meters but also use this plug in for my pro tools set-up: http://www.zplane.de/products/plugins/ppmulator

More reading matter on loudness here: http://tech.ebu.ch/loudness

[John Willett]

Originally Posted by Jody Arnott

The standard is still -24LKFS here in NZ..

Maybe we're behind the times a bit? This is straight from the technical requirements document from the Commercials Approvals Bureau:

"The audio loudness of a commercial must be normalised to -24LKFS. Measurement should be to ITU BS.1770-3 standard and related documents.".

So, is there any way to tell which standard my version of Avid is using? The basic audio monitoring tool doesn't seem to have a function to record the average loudness, only peak. Honestly, I don't have a lot of experience with audio normalisation, especially for broadcast. So any tips are appreciated.

You will need a loudness meter and not a standard meter to monitor to this standard.

I would discuss this with Avid to make sure you have the correct metering.

And a modern Loudness meter will be switchable to measure to the -23LUFS standard or the -24LKFS standard.

So - check with Avid.

[Rick Reineke]

They are numerous loudness meter plugins available.. the 'WLM' for instance.
Broadcast Loudness Meter Plugin - WLM | Waves

[Jody Arnott]

That looks perfect. However, at risk of sounding cheap, I'm trying to find a free one.

I very rarely do broadcast work (maybe once a year, if that), so I can't justify the cost of purchasing one at the moment.

[Rick Reineke]

ToneBoosters has a free demo that works well. The Audiocation loudness meter is another free option if they have your PTs plugin format.

[Jody Arnott]

Originally Posted by Rick Reineke

ToneBoosters has a free demo that works well. The Audiocation loudness meter is another free option if they have your PTs plugin format.

Excellent, thanks very much :)

[John Willett]

Originally Posted by Jody Arnott

That looks perfect. However, at risk of sounding cheap, I'm trying to find a free one.

No chance - these have cost a great deal of money to develop.

However - you may find a limited free-trial version of one with, say, 30-day usage.