How to turn off volume normalization when streaming from library.

Are you really sure Sonos does volume normalization? There’s a lot of complaints on the forum that Sonos does not normalize Spotify for instance. So it would seem strange Sonos would normalize playback for music coming from a NAS - without an obvious setting to not normalize……

It would be good to hear from others.

Depending on the tags Sonos will apply some volume adjustment to library music. It's not controllable, and it's a bit half baked. 

What format are the tracks? How were they ripped? 

Is this documented anywhere, please?

It used to be, but I can no longer find the article. Perhaps because support is so patchy Sonos decided not to publicise it any more.

There have been requests for at least a decade for Sonos to sort it all out. I guess that since local library play has now slumped in popularity it’s fallen off the bottom of the to-do list.

From a hazy memory and a quick search here:

• Sonos takes note of the REPLAYGAIN_TRACK_GAIN tag in e.g. FLAC, but only to a limit of +/-10dB adjustment. Moreover positive gain is limited by available headroom and I seem to recall that positive gain didn’t scale as much as expected.
• Sonos takes note of the iTunNORM tag in ALAC, but I’ve no experience of using it.

I still have REPLAYGAIN_TRACK_GAIN set on my FLAC tracks, which does work to a degree.

Many thanks for the info :-)

Can we get an option to turn this off?

Does anyone know if the Sonos Port supports MP3Gain’s Track Gain settings in Music Librabry MP3s?  I’ve spent years normalizing all of the tracks in my MP3 collection using this protocol, but it doesn’t appear to work w/ Port. 

It’s tough to understand this, since in my experience MP3Gain actually modifies the volume scale factor in each MP3 frame. Sonos would have no option but to play the scaled content. In fact it wouldn’t know that the content had been scaled at all.

Perhaps I should have asked the question this way:  Does anyone know if the Sonos Port MP3 decoder actually reads gain headers frame by frame as a track is decompressed or if it only reads the ReplayGain normalization tag at the tail end of the track? 

@ratty: In theory, and according to the way MP3Gain was designed, you should be right.  But MP3Gain is an old protocol and I’m wondering if the Sonos developers simply moved past it in writing the MP3 decompression software for the Sonos Port MP3 decoder.

Some more information to add after further investigation:  I kept track of the albums in my library where there was no volume normalization.  Sorting these albums by their “encoder” tag, I found that Sonos does recognize MP3Gain’s Track Gain headers in my MP3s that were encoded using LAME or Windows Media Player, but not in any of my MP3s that were encoded with iTunes (versions 3.x, 6.x, 10.x and 12.x in my library).  Odd.

So, I’m just going to re-encode the tracks using LAME and then re-process the new tracks w/ MP3Gain.  Sorry I don’t have any other technical insights to offer.