[MLA] Spotify’s plans

[Bob Katz]

On 10/31/19 7:02 PM, Grimm | Eelco wrote:
> Hi Bob,
>
>>> Right. AFAIK all tracks of an album are attenuated with equal amount.
>>
>>
>> That's ambiguous, it could mean several things. Please rephrase.
>>
>
> "If loudest track of album = -8 LUFS, attenuate all tracks of album by 
> 3 dB before encoding".


Yes, now I understand what you meant.


>
>> You're saying that half a cake is better than none. I'm saying that 
>> if you have millions upon millions of songs, getting it done right is 
>> a priority. So if it's not right, keep working until it is, no 
>> compromise.
>>
> AFAIK Spotify is the only streamer who intends to apply any 
> attenuation before encoding. We should applaud them for that, even if 
> attenuation to -14 LUFS would be better than to -11 LUFS.
>
> That being said, what we could in fact recommend as an alternative is 
> that they attenuate to -14 LUFS before encoding and then use the 
> metadata to not just align to the low loudness target (-23 LUFS), but 
> also to the high loudness target (-11 LUFS). In the latter case some 
> clipping may eventually occur, but the default -14 LUFS target will 
> perform better in general.


There has to be an algorithm that would avoid clipping in those 
situations. E.G.: If it would overload, then reduce gain. You can point 
out that normalization by any standard (even LUFS) is not perfect 
anyway, so a little error with some songs being 1 or 2 dB soft is not a 
tragedy compared to clipping.




>
>>> I am not 100% certain that Spotify does not apply positive gain and 
>>> compression in #3, but what I recall is: compression is only used 
>>> for ‘Loud’ playback at -11 LUFS, and this compression is not 
>>> performed in the app, but stored on the server.
>>
>>
>> I tagged you in a thread where Sigurd proved using John Cage's "4:33" 
>> that Spotify upward normalizes and peak limits all three targets. 
>> Though it would be very rare to find something below -23 LUFS, that 
>> extreme case proves that the algorithm is in use.
>>
>
> You are right: so there is indeed upwards compression in use at the 
> -14 LUFS target. We should disencourage them from that.


Yes, upward normalization is naive. Way back in the day when Dolby 
designed dialnorm people should have followed their lead, and recognized 
the need for an attenuation-only system.




Bob

-- 

If you want good sound on your album, come to Bob Katz 407-831-0233 
DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital Domain 
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