The implementation of the Spotify in Sonos system differs from the normal way of running the Spotify program on PC or mobile phone. In Sonos you can’t control the normalisation setting at all. I asked about this limiter issue from Sonos and Spotify.

Spotify replied that they are not manipulating the ogg files in any way and they are as is. Sonos claims that they are also streaming the ogg files as they are from Spotify. So this alleged limiter is either implemented at the user’s PC during the ogg vorbis decompression or Spotify is manipulating the audio files during the ogg vorbis file creation. If the limiter is applied at the decompression it could be that the Sonos system doesn’t apply it.

What comes to Neal Mathews comment on the limiting: One can never be sure about the source material that has been provided to Spotify by the record companies. Many times there can be several versions of the same record available in Spotify. Typically the newest remastered versions suffer from the loudness war type of limiting. Quite often the remastered version is also the only one available in Spotify. You can’t compare the audio files unless you are sure that the originals are the same.

Every time the horns stab, the limiter pumps horribly. Not just “yeah , if I pay attention, I can hear it”. Yes, this is an extreme example because of the dynamic range of this track, but this is just pathetic. Yes, I’m an audio engineer, but I really do understand enough to make allowances as to what to expect from a streaming audio service. Pandora does a much better job of limiting/normalization dealing with the exact same issues.

Bottom line: Spotify could do a MUCH better job with the implementation of necessary audio dynamics, and it is needlessly damaging the listenability of their service. So to your question: “Is limiting high-level decoded audio the right thing for Spotify to do ?” my answer would be… Absolutely not, at least with the particular settings they are using.

For some reason high frequencies (like made by hi-hats, or in human voices when pronouncing the letter s) sound slightly distorted. It actually sounds a tiny bit jittery (as if the hi-hat sound is mixed with static), though it’s clearly a different kind of distortion than clock-jitter: much less intrusive.

Lower frequencies sound a tiny bit less accurate than on the cd version. Can’t put my finger on that but it just feels a little less “tight”.

All was tested with some Michael Jackson tracks, because they’re mastered pretty well (unlike most music these days) and contain lots of high frequencies. I notice it on all Spotify music and hope it’s a processing thing in the client that they can solve. Also it was tested by connecting my pc to my av-receiver by hdmi (set to 44100 Hz 16-bit pcm sampling). Cd’s were played by the same pc so all hardware was 100% equal.

Conclusion:
Spotify is a great service and sounds great. My audio-setup allows for great detail in the audio and this is something Spotify can’t deliver. I’m pretty confident you won’t be able to hear the difference on a set of pc-speakers or even a normal consumer music system though.

I should also qualify what I said in that reply, actually – if you’re listening to a track and it’s louder with normalisation on, then you *may* be hearing Spotify’s limiter working, and it *may* sound better with normalisation off – or, there may have been plenty of headroom in the original track, in which case there will be no limiting. And, the effect of the limiter will be quite mild on most music, anyway.

Finally, if you listen to lots of modern stuff, where the levels are “up there” already, then personally I don’t want to hear another limiter working, even just to deal with overlevels in the decoded stream, so again I would leave normalisation on…

This stuff is never simple !

Bottom line – if the track sounds quieter with normalisation on, it has NOT had extra limiting or processing.

@VIOZ – Spotify applies the gain change, then passes the audio to the computer for playback. So it changes the data, but only a gain reduction. Strict ReplayGain adjustments involve quite a big reduction, which may cause the differences you’re hearing – but, it’s important to match the level again for any comparisons ! As soon as you compare two things at different playback levels, you can’t make accurate comparisons. Do the tracks still sound flat/lifeless if you turn them back up again ?

@Erik – There are two possibilities:

1 – If the tracks get louder with normalisation ON, then you are hearing the limiter working on a dynamic track, and yes – in this case they will sound better with normalisation off.

2 – If the tracks get quieter with normalisation on, then I disagree – the limiter will not change the sound at all because all Spotify does is turn the level down. No listening needed, I’ve seen the raw data to prove it, now.

If you prefer the non-normalised sound when level-matched to the normalised version, it’s just because you prefer the limiting of the higher level level.