Spotify - normalization vs dynamic range compression

[darrenyeats]

Thanks Julf.

 

[steve_1979]

In case anyone was wondering what track was used for this test it was It's Oh So Quiet by Bjork. The two reasons for this are:

1. It has quite a large amount of dynamic range which should make any changes easily noticeable in a listening comparison.

2. The name of the song seemed ironically apparent.

 

[steve_1979]

Isn't it just adjusting all tracks to the same level so you don't have to adjust with your own volume control?

No it is reducing the dynamic range which is a different thing.

Reducing the dynamic range of a track sucks the life out of the music. It feels less dynamic! Any this is exactly the effect that I can hear when comparing the two versions of this track when played back at the same apparent volume level.

 

[steve_1979]

I've just noticed that with the new Spotify update yesterday they've now completely removed the option to 'play all tracks at the same volume' so I've retested the Bjork track to see if Spotify is forcing us to use dynamic range compression whether we want it or not. ...and the result is good (albeit very suprising!)

Spotify now seems to have more dynamic than it did originally with either the 'play all tracks at the same volume' option switched on or off so that's an improvement. The tracks also seem to have had their volume adjusted to that the peak reaches 0dB without clipping.

Here's the results to compare to those in post 1 of this thread.

There are several other comments and blogs around the web saying similar thing to what I've found. It seems that Spotify have been listening to their customers.

 

[FireMoon]

Just a heads up and yes it's being pedantic however. The "dynamic range" of a piece of music is not what people think it is, a measure of the difference between the loudest and quietest parts of a piece. The "dynamic range" is how well one can hear a quiet part of an arrangement against a "loud" part.

For instance, when the whole band kicks in on a loud track and you can't hear the hi-hats clearly, the bass suddenly vanishes and become nothing more than a thrum that has no real clarity at all, leading edges of notes vanishing etc etc, that is a, lack of dynamic range I understand where the confusion arises from and maybe it's heading the way of "transpires" as an accepted phantonym however, as it stands, it's a term that is as misused as the L2 limiter.

 

[cooky1257]

If the peak level is already 0dB how do you expect normalisation to work and any increase in average level not need an equal amount of compression in order for the peak level to remain below 0dB? You can't go over 0dB.

 

[steve_1979]

Bad news! Very bad news!
It's seems that I may have spoke too soon yesterday.

Today I remembered that we have another computer in the house with Spotify on it so I booted it up and sure enough it still has the old version of Spotify installed so I've been able to do some direct comparisons and the results show a big drop in sound quality!

Using the track 'Radio Protector' here are the results.
The right pictures shows the old version Spotify with the 'Set the same volume level for all tracks' option turned off.
The left pictures shows the new version of Spotify which has this option removed.

EDIT - Images removed because I made a mistake.

 

[Obi1]

Please send the results to Spotify and ask them why they have made this change.

 

[steve_1979]

Please send the results to Spotify and ask them why they have made this change.

They're already aware of it.

https://community.spotify.com/t5/Sp...ack-volume-normalization-toggle/idi-p/1040449

There's a lot of hate for the new Spotify update on their forums at the moment. The removal of fthe option that allows you to turn of the 'Set the same volume level for all tracks' is just one the reasons.

 

[steve_1979]

Hmmm. There's something odd going on here.

I've just deleted the Spotify cache and reinstalled the previous version of Spotify (0.9.15.27) and the result is the same as it was with the new one.

TBH I'm a bit confused by these results now. Maybe they've just changed the version of the track 'Radio Protector' to a different one with different mastering? I'm not sure what to make of this. I'll investigate some more tomorrow but it's getting late now.

 

[steve_1979]

OK I think I've sussed it now. The track 'Radio Protector' that was stored in the Spotify cache on my old computer is indeed different to the version that Spotify are currently streaming now. I don't use that computer very often so the track in the Spotify cache is probably several months old and seems to be a different version with lower volume and more dynamic range than the new one so the comparison that I made yesterday is irrelivent as far as comparing the versions of Spotify are concerned. Sorry my bad. I should have deleted the cache first to make sure that both versions of Spotify were using the same file.

I've now compared a few other tracks in both the old and new versions of Spotify (after deleting the cache this time) and it seems that the new version isn't forcing us to listen with the dynamic range compression switched on. Great news!

However both the old and new versions of Spotify do always seems to have very slightly different results but they are always very very close. I'm not sure why they are different but my guess is that there is some sort of processing still being applied and they have now tweaked this processing. For a better explanation of what I mean read the section half way down in this link here where it explains about Inter-sample decoding peaks: http://productionadvice.co.uk/wrong-about-spotify/

QUOTE

"Fourth - Spotify’s options clearly allow you to enable or disable “Volume Normalisation”. I wrongly assumed that Spotify disabled all processing when normalisation was off.

Big mistake.

As I described in the original post, Spotify has a limiter which stops quieter, more dynamic tracks being distorted when their volume is boosted by the normalisation feature. What I didn’t realise is that this limiter is always on - even when “Volume Normalisation” is off.

At first sight this may sound bizarre – why would you need a limiter, if you aren’t changing the level of any songs ? And even if it’s on, why would it be doing anything to audio whose level hasn’t been changed ? The answer is the final factor I failed to take account of:

Inter-sample decoding peaks

There’s a reason Spotify’s limiter is enabled all the time – that’s because most CDs recorded today, when decoded from mp3, AAC or Ogg Vorbis files – as in Spotify’s case – contain inter-sample peaks. There’s not enough space here to discuss them in detail, but the short version is – most CDs mastered in the last few years will be going “into the red” when they are decoded.

So, a player like Spotify needs to make a decision – should the resulting audio just be allowed to clip, should it be turned down, or should it be limited, in an attempt to minimise the distortion ?"

 

[steve_1979]

The newest update of Spotify has brought back the option to turn off the volume equalisation function that reduces the dynamic range.

Thank you Spotify.