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Peter Mc
August 23, 2016
Question

Connect no longer bit-perfect?

  • August 23, 2016
  • 450 replies
  • 29769 views
It looks like the Connect is no longer bit-perfect. Here's my evidence: let's discuss this.

First, I constructed a wav file of pink noise with amplitude ramping up from zero to digital max and back to zero.
I play this through my Connect and record the SPDIF output from the coax output into my PC.
The recording uses a Scarlett 8i6 audio interface set to use the Connect as master clock.
I record into a DAW (Sonar) multiple times - all instances are identical.
However, this recorded signal is not quite the same as the original wav file - it can be up to -21dB different.
See https://www.dropbox.com/s/t8od479xo9hi5el/connect_diff.PNG?dl=1
Note the expanded scale on the difference (third) track.

It looks like the difference gets larger when the signal is larger. To confirm this, I import the
original and difference files into Matlab and plot the raw data (difference vs original). There is clearly audio compression
happening here. See https://www.dropbox.com/s/p1yq6wcqafvnhaj/diff_vs_orig.png?dl=1
The scale is such that digital maximum is 1.

There also appears to be a slight bias when the waveform is negative and the signal is below the
compression threshold. See an expanded version of the previous plot
https://www.dropbox.com/s/9001tl9mkle4wly/diff_vs_orig_zoom.png?dl=1

Happy to answer questions about the method and conclusions.

Cheers, Peter.

p.s. Volume is set to fixed - I haven't tried variable.
In a loopback test (8i6 out from DAW to 8i6 in, no Sonos gear involved), I get bit-perfect cancellation.
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    450 replies

    February 23, 2017


    It should still be really simple to disable all DSP in fixed volume mode and provide bit-perfect output.

    Did you notice any audible improvement in the normalisation feature performance subsequent to this change? If you did not, and nor did anyone else, the obvious question is that the above should not be a big project needing resources?
    Peter Mc
    Peter McAuthor
    February 23, 2017
    Are you asking me? I guess I don't understand the question. What change are you referring to?
    "The presence of those seeking the truth is infinitely to be preferred to those who think they've found it" - Terry Pratchett
    February 23, 2017
    The first question was to you, the second slanted towards Sonos! To you - do you find that volume normalisation now works noticeably better than it did when the Connect output was bit perfect. If the answer to that is no, the second question arises.

    I have found no difference in how volume normalisation doesn't work well from the time I am using Sonos - 2011.
    Peter Mc
    Peter McAuthor
    February 23, 2017
    I wasn't even aware of volume normalisation when the brick-wall limiter got introduced (version 6.0 of the software if I remember correctly). I've done a lot of learning since then. And I certainly can't ABX this change! So I can't answer your question.
    "The presence of those seeking the truth is infinitely to be preferred to those who think they've found it" - Terry Pratchett
    Enthusiast II
    February 27, 2017
    I think this was introduced when certain tracks caused some serious clipping, Mainly from streaming services. It was almost like the Sonos units themselves were adding gain.

    I know Meridian have a -3db across all channels on their processors on the volume side, this is in case you want to add any DSP functions, such as their Trifield setting, where increasing the width might actually add -0.5db to the main speakers and push them into the realms of clipping.

    But any normalisation should be done in the analogue domain, not applied in the digital domain, well certainly not when the output is set to fixed.

    This should be a very easy firmware upgrade.


    I actually came on here to ask if there was a new higher end product coming out that would allow higher res files and MQA decoding as after trying things like the Meridian MS200 and even their cheap explorer 2 (£129) going back to the Connect sounds incredibly flat, almost like the soundstage has collapsed. Seeing this thread might explain why that now is, not the fact the Sonos Connect is really bad, just that it is reducing volume in the digital domain and therefore throwing away resolution.






    I really like the Sonos gear, my Play 5's are fun, the Connect Amp does a fine job for the bedroom, the interface and the way I can search Soundcloud, Spotify and Tidal is great, plus being able to stream from my iPhone is also nice, and now you can see the Sonos gear as endpoints/zones from Roon it is a even better, but I do wish there was a higher end unit for serious listening on the main system.

    With all the other options out there now, and with the price increases many are jumping ship, and the only reason is the fact audiophile has moved on from 16/44, it has been 12 years now since Sonos came out, my ZP100 is 12 years old, my ZP80 (or maybe it's a 90) is probably 11 years old.
    They sit there happily playing, but where is the product to get me buying more from you?

    If you brought out a Connect pro that played Tidal's MQA files and the HiRez (even if it were up to 24/96) I would buy it, as would many more out there. So come on, let's not pretend we are in the early days of music streaming anymore, let's offer some new product, and give us a reason to buy more gear from you.
    chicks
    February 27, 2017


    I actually came on here to ask if there was a new higher end product coming out that would allow higher res files and MQA decoding as after trying things like the Meridian MS200 and even their cheap explorer 2 (£129) going back to the Connect sounds incredibly flat, almost like the soundstage has collapsed. Seeing this thread might explain why that now is, not the fact the Sonos Connect is really bad, just that it is reducing volume in the digital domain and therefore throwing away resolution.

    With all the other options out there now, and with the price increases many are jumping ship, and the only reason is the fact audiophile has moved on from 16/44, it has been 12 years now since Sonos came out, my ZP100 is 12 years old, my ZP80 (or maybe it's a 90) is probably 11 years old.
    They sit there happily playing, but where is the product to get me buying more from you?

    If you brought out a Connect pro that played Tidal's MQA files and the HiRez (even if it were up to 24/96) I would buy it, as would many more out there. So come on, let's not pretend we are in the early days of music streaming anymore, let's offer some new product, and give us a reason to buy more gear from you.


    A "Hi Rez" Connect might sell in the thousands, or perhaps tens of thousands. The Play:1 sells in the millions. I doubt Sonos will produce something that only self-deluded audiophiles can "hear" a difference with.

    BTW, Sonos devices use a 24-bit buss internally. They're not discarding bits within the normal volume adjustment range.
    ratty
    February 27, 2017
    The 'usual idiots' who request a level-matched double-blind test?
    jgatie
    February 27, 2017
    The 'usual idiots' who request a level-matched double-blind test?

    Yes the 'idiots' who would like to see objective scientific evidence rather than believing marketing hype and claims of superhuman hearing or violations of the laws of physics. Those idiots.

    The world is truly upside down. Next thing we know, the cast of 'Finding Bigfoot' will get accepted to Mensa.
    Enthusiast II
    February 27, 2017
    The Sonos connect has now jumped from £279 to £349, the Bluesound Node at £499 is starting to look like great value.
    The Bluesound is now a Roon endpoint too.

    The point is, as a Sonos customer where do I go from here? There is no next level, or even a way to play todays formats, so the answer is to another brand, which as someone in the Sonos eco system already seems somewhat of a shame.

    I like Sonos as they do update their gear with firmwares to keep it useful, and useful some 12 years later in tech terms is very good going. But there are lots of customers who would like a Sonos Connect that does all the formats that are out there today, not just the ones we have had for the last 30 years.

    Adding a new connect that does the current formats they don't lose any customers, all their old gear will still do what it does today, but they will open themselves up to another market, and if they grab a share of that market I can bet many will suddenly buy a Play 5 for the kitchen and a couple of play 3s for the bedroom.
    It is a great system with great software and integration, but right now not having the kit for peoples high end system is going to see people having a rethink.

    Every forum I am on that is not music related, many are starting to try other brands, whether than Yamaha, Nad/Bluesound, Roon with a RaspberryPi etc. etc.
    Maybe that is more a UK thing because of the price increases? But it has been pretty vocal on the forums I use.


    I just looked at your kit, I agree, with your kit better quality is pointless.
    That is not a dig, that is the point I was making about my my Play 5 being fun and my Connect Amp (ZP100) doing a fine job, they are great for what they are.
    But there is a serious difference between playing Tidal through the Connect into my Meridian DSP speakers compared with the Meridian MS200 I just borrowed (£299 so £50 cheaper than the connect) and even with my Macbook going straight into the speakers playing back 24/96 through their Masters Series albums (MQA). Even my wife gave a "Wow!" and she listens to the radio through the TV speakers most of the time! 😉
    Enthusiast II
    February 27, 2017
    The 'usual idiots' who request a level-matched double-blind test?

    Yes the 'idiots' who would like to see objective scientific evidence rather than believing marketing hype and claims of superhuman hearing or violations of the laws of physics. Those idiots.

    The world is truly upside down. Next thing we know, the cast of 'Finding Bigfoot' will get accepted to Mensa.



    Just listen to it.

    If you can't hear it fair enough. If you can then decide whether it is worth the price.