[MLA] Loudness example with distortion on Sound Check

[Bob Katz]

On 10/13/18 4:22 PM, Ian Shepherd wrote:
> Another example of why we need lower normalisation reference levels sooner rather than later, though...!

How about saying: "Lower normalization reference levels, no positive 
gain and no peak limiting."

It's amazing how the streaming services reinvent the wheel wrong again 
and again and don't consult with experts like us. Even Dolby got it 
right historically with Dialnorm always being a downward normalization 
approach. Thanks to efforts of Thomas, Eelco and others, some of the 
services are just beginning to listen to us.

In our recent conversations, I pointed out that it's totally impractical 
to expect or even talk about any streaming player applying attenuation 
to avoid overs just post the decode stage. Therefore even though the 
clipping is not baked into a well-made encoder, it has to be the 
responsibility of the mastering engineer to prevent decoder clipping by 
reducing the level that will be applied to the encoder if necessary. 
Mastering engineers have to bake that level into the fixed point file 
that we supply to the distributors.


Bob K





> Ian
>
>
>
>> On 13 Oct 2018, at 17:35, Thomas Lund <thomas at lund.one> wrote:
>>
>> Hi Bob,
>>
>> That’s still an excellent example, and points to the danger of allowing positive gain, especially when having a bad limiter in the system.
>>
>> cheers,
>> Thomas
>>
>>
>>
>>
>>> On 13 Oct 2018, at 18.21, Robert Ludwig <gatewaybob at mac.com> wrote:
>>>
>>> Hi Ian,
>>>
>>> As you like to write about Loudness I wanted to give you something I came across before you joined the group.
>>>
>>> We were once on the lookout for real world examples of tracks that needed boosting on iTunes Sound Check and that boosting would cause distortion I came across this example in my iTunes library.
>>>
>>> Attached is a 5:26 Victoria Mullova & Kristian Beuldenhout Beethoven Violin Sonata movement on iTunes that peaks at -2.8 dBFS on the left channel at 4:26 on the 3 loud chords.
>>>
>>> Sound Check says it needs to be raised to +8.8dB!  It technically has 6dB of distortion at that peak if Sound Check was being used.
>>>
>>> BS-1770 says it has a Program Loudness of -27.7, so if iTunes had used ITU as a measurement it would have raised it even more!
>>>
>>> Best,
>>>
>>> Bob Ludwig
>>>
>>>
>>> <02 Victoria Mullova & Kristian Bezuidenhout.m4a>_______________________________________________
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>>
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-- 

If you want good sound on your album, come to Bob Katz 407-831-0233 
DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio *Digital Domain 
Website <http://www.digido.com/> No trees were killed in the sending of 
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