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Peter Mc
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

      Show previous replies
      jgatie
      jgatie
      December 1, 2017
      I never commented on Roon specifically. Ever.

      So the person who earlier today wrote “It's not Roon I'm against, it is the constant pimping of Roon in threads where it most certainly does not apply” is a different jgatie?

      Nice stripping of context, did you think I wouldn't notice? The statement was about before today. You specifically commented that I become "quite upset when a Roon is mentioned". As stated, I never commented anything about Roon before this thread, I only mentioned above Redbook. Even if you do count today's post as mentioning Roon, I made no comment on Roon itself, I specifically said I have nothing against it. Real harsh criticism there. I'm a real Roon hater. :8
      Ditte
      Ditte
      December 1, 2017
      Gentlemen, we appreciate a good discussion, however you're taking it a bit too far here.
      Can we get this topic back on track, please? 🙂


      All the best,
      Ditte
        gizze
        Enthusiast II
        January 6, 2018

        Be careful. One of the frequently posting Sonos fanbois here gets quite upset when a Roon is mentioned. He believes any mention of a Roon to be a “hidden agenda.” Oddly, he seems to have nothing against any other apps that permit direct control of Sonos speakers, including Spotify and Tidal. But you’re right, music played through Roon sounds great on Sonos, with the added plus that Roon will downsample higher-bit-rate files that normally won’t play on Sonos.


        It's not Roon I'm against, it is the constant pimping of Roon in threads where it most certainly does not apply. I would say the same about any other product constantly shoehorned into threads where nobody asks about it. Also, use of the term "fanboi"considered insulting and abusive, and often leads to having your posts edited by the mods. Everyone is entitled to their opinion without being subject to personal attacks or use of derogatory terms.

        Haha, wonderful.

        I popped in to see how this thread was going, and this was the first page I looked it.


        jgatie, you do realise you are quite famous on many of the hifi forums.
        We had a bit of a meet up the other month, and when somewhere asked "Are there any down sides to going Sonos as source?" Someone replied "Yeah, you have to listen to people like jgatie on their forums!"
        That tickled a few us.

        I'm sure you're a nice enough lad, maybe try and reign it in a bit, some people in life will like different things to you, accept it and you will feel much happier in life.




        I am running Roon with a Raspberry Pi and a Meridian Explorer 2 as my dac pre amp. Stunning, really, really stunning.
        £133 as well!
        It replaced my Meridian MS600 and Croft Pre amp at £3000 which I think says a lot about just how good it sounds.

        Roon is something else, I wasn't sure bout it at first, just seemed a lot, but I sold my 2 connects and paid for lifetime Roon and the 2 raspberry pi endpoints with the money.
        Still think Sonos is wonderful in the way it integrates Tidal, Spotify, Soundcloud etc.
        But having Airplay on the Pi along with Tidal and that wonderful interface and search of metadata means we just use the Play 5s now as Roon endpoints.
        jgatie
        jgatie
        January 6, 2018
        That's "rein". :8

        And if that was an audiophile forum, I can think of no higher achievement than to annoy a group of audiophiles. I can now die a happy man.
          Kumar
          January 7, 2018

          jgatie, you do realise you are quite famous on many of the hifi forums.
          We had a bit of a meet up the other month
          In what words is Hydrogen Audio spoken of in such places?
          gizze
          Enthusiast II
          January 11, 2018
          That's "rein". :8

          And if that was an audiophile forum, I can think of no higher achievement than to annoy a group of audiophiles. I can now die a happy man.

          My word, my awful grammar. Must be because you're king of the forum.
          jgatie
          jgatie
          January 11, 2018
          From Merriam Webster

          Definition of rein

          1 : a strap fastened to a bit by which a rider or driver controls an animal —usually used in plural
          2 a : a restraining influence : kept a tight rein on the proceedings

          Also from M-W

          Definition of rein in

          1 : to limit or control (someone or something) Congress must rein in spending. You had better rein that kid in before she gets hurt.
          2 : to make (an animal) stop by using reins The rider reined in his horse.


          🆒
          Ryan S
          Ryan S
          Retired Sonos Staff
          January 11, 2018
          @gizze, we appreciate the engagement, but let's cool it on the personal attacks.

          Everyone, we're way off course right now, let's bring it back on topic.
          Mark good posts by pressing the like button, and select the best answer on questions you've asked to help others find solutions.
          Sononos_fan
          Enthusiast II
          January 11, 2018

          My word, my awful grammar. Must be because you're king of the forum.

          That reign vs rein bit made me lol.

          Personal attack, where?
            gizze
            Enthusiast II
            January 18, 2018
            @gizze, we appreciate the engagement, but let's cool it on the personal attacks.

            Everyone, we're way off course right now, let's bring it back on topic.

            What personal attacks?

            Your forum favourite, jgatie, is one of the reasons many can't be bothered with posting on this forum, but you protect him.

            How about you take a look at my post asking for help on an issue?

            https://en.community.sonos.com/troubleshooting-228999/distortion-since-last-update-on-play-5-and-on-connect-amp-6763208
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