Skip to main content
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.
    This topic has been closed for further comments. You can use the search bar to find a similar topic, or create a new one by clicking Create Topic at the top of the page.

    450 replies

    March 12, 2017


    If you weren't such an opinionated bigot


    Your constant droning on is very bigoted.

    It is boring, it is rude,

    there are so many threads with the same nonsense

    I think you talk shite

    but why tell everyone it does matter to that they are wrong?!


    In any of my posts since 2011, and they are a few more than your 55, I don't recall using phrases as objectionable as the ones quoted above; if I have and someone shows them to me, I will apologise. The last one quoted isn't rude of course, that has been quoted for this response:
    This is not a private conversation between people on two sides of a divide. Others that either have or are considering Sonos are also the audience and it does matter to them if you are wrong.

    And here is the aspect of the problem that you are probably ignorant about - this story has been playing out for ten years now and no one claiming the kind of things you have has ever been able to back up their subjective claims with anything of more substance. So when someone new comes along here singing the same song, being short - as opposed to rude - with them is natural; all the more because none take the trouble to read the earlier conversations. Some even admit to not having read the full thread.

    By the way, you will not find any of the regulars being short with people that ask the same troubleshooting help over and over.

    And then there is this - consider the two statements below:
    1. Sonos kit is capable of being as good as the best audiophile system

    2. Sonos kit delivers better sound quality than any audiophile system out there

    There are people here that don't even fully understand ABX, that will demand an ABX proof for statement 1.

    And there are those that will not accept that statement 2 requires such proof, even where " Sonos" and "Audiophile system" are replaced by "Hi Res" and "CD quality". By the way, no one accusing me as they often do of being a Sonos fanboy will have seen Statement 2 as written above in any form, from me - or from any of the regulars.

    Then there is the "in my opinion" thing going around. People that know better, understand where and when it is to be inferred. Would it help if I just added " IMHO, YMMV " to my signature?! Doing more than that is tiresome, silly and inefficient, and I do not intend doing that just to please those that have run out of counter arguments that have a leg to stand on.
    Peter Mc
    Peter McAuthor
    March 12, 2017
    People that know better, understand where and when it is to be inferred.

    Who are these people that are able to judge that claiming someone is a liar is inferred opinion, but that claiming MQA sounds better is a statement of fact? And how do they tell the difference?
    "The presence of those seeking the truth is infinitely to be preferred to those who think they've found it" - Terry Pratchett
    March 12, 2017
    I am not sure I understand you; to the extent I can, my inference is that both the statements you have made are opinions.
    jgatie
    March 12, 2017
    I never called anyone a liar. I stated the quote that was printed was a lie, i.e. the opposite of the truth. Big difference, especially when the person later claimed he was misquoted.

    As to the other, I've repeatedly stated that MQA probably does sound better. So fact or opinion, I've got no problem with either. Hi-resolution audio often sounds much better than CD.
    Peter Mc
    Peter McAuthor
    March 12, 2017
    Because of the conversation around this post (before and after). It seems people who claim hi-res sounds better cop a beating on this forum for not providing suitable evidence of what is taken to be a statement of fact, whereas a claim that someone is a liar is to be inferred as opinion and therefore need not be backed up with evidence. How do your "people that know better" tell the difference between these two scenarios?
    "The presence of those seeking the truth is infinitely to be preferred to those who think they've found it" - Terry Pratchett
    Peter Mc
    Peter McAuthor
    March 12, 2017
    I never called anyone a liar.

    Mr. Reiss is lying in his PR statement.

    I stand by my accusation. Dr. Reiss is lying in his PR statement.

    ...in reality a lie, attributed directly to you.
    "The presence of those seeking the truth is infinitely to be preferred to those who think they've found it" - Terry Pratchett
    March 12, 2017
    It seems people who claim hi-res sounds better cop a beating on this forum for not providing suitable evidence of what is taken to be a statement of fact, whereas a claim that someone is a liar is to be inferred as opinion and therefore need not be backed up with evidence. How do your "people that know better" tell the difference between these two scenarios?
    Sorry, I still don't get you. In my view, both statements obviously are opinions, I don't need the "in my opinion" caveat to be attached to each to infer them to be so. And if challenged, both need to be backed up. I see that jgatie is doing just that with respect to the second, so I will not add anything there except to say that he is making a fine point of distinction that needs to be discerned.
    Peter Mc
    Peter McAuthor
    March 12, 2017
    This post. It's the shill statement, not the lying one, that I should have used as an example. I challenged jgatie to provide evidence of his statement that "This study was a carefully crafted shill for the Hi-res audio industry". He claimed that everyone else would have already inferred that his statement was an opinion, and therefore he provided no evidence to back it up. As jgatie also said, " It's once someone starts making definitive claims that they need to start giving proof." How very convenient that he considers that his statement should be inferred to be an opinion, perhaps by your "people that know better". Do you start to understand now the double standard being applied here?
    "The presence of those seeking the truth is infinitely to be preferred to those who think they've found it" - Terry Pratchett
    March 12, 2017
    I challenged jgatie to provide evidence of his statement that "This study was a carefully crafted shill for the Hi-res audio industry".

    . Do you start to understand now the double standard being applied here?

    I see what you mean, and I am doing something that isn't usually wise - jumping into a conversation between two people - but this may just as likely be cross talk and not double standards.
    Here is what would probably have yielded better results:
    Statement: "This study was a carefully crafted shill for the Hi-res audio industry"
    Response: "Why do you think so?" or another form of the same question, asking for a justification of the statement. And it doesn't matter if the statement is an opinion or a fact - or whether it was prefaced with the " In my opinion". In any of these case, the response is legitimate.
    Somehow I doubt that the response to the response above would then have been on these lines:
    " I just think so, it is my subjective opinion and I don't have to say why I hold it".
    March 12, 2017
    Just for the heck of it, let me give what would my response have been if asked!

    I'd have said that the author of a study that found and reported some perceived differences at times between Hi Res and CD based on a meta analysis of reports, some of admittedly dubious quality that his study relied upon, allowed himself to be directly quoted as saying things in favour of Hi res found by his study, that his own study did not admit to have found. And this was cleverly done, with the admittedly wrong quote only accepted to be so where and when challenged.

    How's that, Ump?!