Question

Connect no longer bit-perfect?


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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453 replies

I I used Connects for many years and I became unhappy with the sound (digital out) a few years ago without being able to figure out why. This does not prove anything of course so I have decided to purchase an old ZP90 (reported as remaining bit-perfect) and once I get my hands on it I will try a blind test against my recent Connect to see what I find 🙂. It will be a few weeks before I do this but I will report back.

I am new here but have a number of Sonos components and looking to add a connect to my main HiFi setup. I am slightly bummed that Sonos does not see the connect as a hifi device. It doesn't need to have awesome components as long as it pushes a perfect stream to my DAC. Was this a hardware change, firmware change, or software change? ZP90 is not affected?
Back in 2011, I got a zp90, wired it to the DAC of a Marantz SACD player wired to a Quad 99/909 driving a pair of Harbeth speakers. In time, I realised that the analog output of the zp90 works just as well, the first step on the road of simplifying my kit to the point that now a 1 pair + Sub sounds just as good to my ears, in my home.

YMMV, but I suggest that getting a Connect still makes sense as long as you are sure that there is life in and intent to use the downstream HIFi kit long enough to obtain value from the Connect.
To clarify, I have a house in a somewhat rural area that has Sonos in every room. I also have a condo in the city that has a high end reciver along with a very solid 2.1 system. I was looking at the connect as a way to bring streaming into that system. After doing a lot a research I have a feeling that the connect will have hardware limitations in the future.
In what way? It will continue to be as good a source to your 2.1 system in future too, so if you do not expect to move to later technologies for music in its space, the Connect will serve.

But since you just want to bring streaming to one system, why not use Chromecast Audio that costs just USD 35 to do so? It also gives you the psychological satisfaction of using bit perfect/Hi Res digital output into a "more superior" DAC, if your HIFi set up has one that takes digital inputs. If not, in truth, the analog output of that device is just as good - in absolute terms, not just "for a USD 35" device.The only disadvantage to it is that you will not get the on body control buttons that Connect has.
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I also think that the changes in the Connect's digital output are the result of a decision by Sonos. Who knows, maybe they decided they wanted to 'voice' the output in a certain way. I am not so sure that the results are not audible though. I cannot back it up with hard science / blind testings etc. I think the OP (Peter Mc) reported he could actually hear the difference so I would not rule out audible differences so quickly.

I used Connects for many years and I became unhappy with the sound (digital out) a few years ago without being able to figure out why. This does not prove anything of course so I have decided to purchase an old ZP90 (reported as remaining bit-perfect) and once I get my hands on it I will try a blind test against my recent Connect to see what I find 🙂. It will be a few weeks before I do this but I will report back.


It seems a shame to let this epic thread die, so how did you get on?

I have two CONNECTs, and they sound as good as anything I've ever owned, using either the digital or analog outputs. However, I confess that I listen with my ears and not with a signal analyser.
You need to get your ears checked...:-))
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You need to get your ears checked...:-))

Yup, that's certainly been suggested, most frequently by my wife. 🙂
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The posts that still show up here are interesting even though I ditched my Connect in favor of an Auralic Aries for my system.

The comments about ears and the age of some of us is of interest to me because I am 72 and, of course, my hearing has deteriorated. You cannot know how many times I have heard people comment I should not waste my money on better sound equipment because I can't hear the difference. That is just not true. I cannot hear the same frequencies younger people hear, but I can still tell the difference between good gear and not-so-good gear. Perhaps the best example is having to sell my Belle Klipsch speakers I bought in 1976 because there is no way they would fit when I moved from a house to a condo. A friend had replaced his Dynaudio Contour 1.8 Mark II speakers with Peak Consult Princess (you won't find them at Walmart) ones having about the same footprint (about 12" x 8"). Side by side in his home, I could definitely tell a difference them. Not frequencies, not volume (we measured), but the Consults were "better". obviously better. When asked to describe, I could only say "presense". He graciously sold me his Dynaudios for a good-friend price. I checked them as free bags on my flight from Phoenix to Cincinnati. Shipping was a super bargain!

At my house, where the Belles were still in the living room, the comparison was not even close. The Dynaudios were clean and clear, just like at my friend's, but the Belles blew them away. Now, I don't mean like shake the house, which they could do -- theater speakers in a nice cabinet after all. But the fullness of the sound, the feeling of "being there" were head and shoulders over the Dynaudios. The were "better". I sold the Belles for more than I paid for them in 1976.

Even "bad" ears can tell a difference. Especially when it comes to speakers. I can most certainly tell a difference between CDs and MP3s, but not lossless FLAC rips. I doubt I, or most normal humans, can tell a difference between 10 gauge wire and some of the exotic stuff. I called Klisch a few years ago and asked about maintenance on the Belles and what wire they recommend. They suggested updating the crossovers (capacitors), but said 12 gauge lamp cord would do just fine for the wire.

One more oddity about "bad ears". I have a pair of Ultimate Ears in-the-ear monitors that I use with a Pioneer XDP-100R (a huge bargain these days with the 300 now out!) portable player playing FLAC rips. My right ear has been affected by Meniere's Disease. Not terribly, but noticeable. The left is hearing like a much younger person. When I use the monitors, the sound is perfectly balanced -- at least my brain makes it so. The quality of the sound is beyond incredible. Plugged into an iPod, they sound muffled playing Apple Lossless, which several test show me the same binary for the music part of the file. If it weren't for the "headphone effect" of being in the middle of the band instead of in front of it, this would be my preferred way to listen to music. I cannot explain the illusion of balance.

Lastly, and the whole point of posting here after about a year, is that perfect hearing is like perfect smell (I'm the "sniffer" in our building, called upon to find the source) or perfect taste. We can't begin to guess what music sounds like to someone with great ears and perfect pitch or what nuances one smells or tastes with "good" and "bad" food. But, good food smells and tastes better than bad even to those without such sensitive senses. Same for sound. Bad ears can still tell the difference, it's just not the same difference.

Hello, Kumar!
I can most certainly tell a difference between CDs and MP3s, but not lossless FLAC rips
It depends on the compression of the mp3. Most of us can tell the difference between a lower quality MP3 and a CD quality rip, but I don't think that it's the same with a 320k MP3. I certainly couldn't in a single blind test.
That is just not true. I cannot hear the same frequencies younger people hear, but I can still tell the difference between good gear and not-so-good gear. Hello, Kumar!
Hello...and I agree with you, but I have no way to prove it and neither the time nor the interest to argue about it.
@pwt: Wives, like customers, are alway right. Anyone else that questions my hearing, I am like Rhett Butler at the end of his patience with Scarlett: I don't give a damn.
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Kumar, Nor do I. I’m very happy with what I’ve got and what I hear. That’s all that matters.

Just got home from a Tommy Emmanuel / Dave Grisman concert in a great venue. Now that’s the way to listen to music. Emmanuel’s guitar playing was so amazing and emotional he had most of the theater in tears.
Now that, I agree with no reservation. There is NOTHING like a live gig. No matter what music, what genre.

On a scale of 10 for that experience, the best HiFi in the world can't cross 7. And the gap down from that 7 to the best of Sonos in a space that isn't too large for Sonos, is a lot less. Sonos would be 6.5, a subjective assessment, but it makes the point. If the brain can do the job of filling in the gap from 7 to 10 to still allow recorded music at home to be heard in a way that satisfies as it does, doing the same from 6.5 to 10 isn't a big deal/stretch for it.
I am like Rhett Butler at the end of his patience with Scarlett: I don't give a damn.
More flouncey, like Scarlett O'Hara when she can't get her own way....
Why am I not surprised that you can't come up with a better response?
Unless I missed something, there still isn't a reply by Sonos to the original question about the Connects not being bit perfect?
I also think that the changes in the Connect's digital output are the result of a decision by Sonos. Who knows, maybe they decided they wanted to 'voice' the output in a certain way. I am not so sure that the results are not audible though. I cannot back it up with hard science / blind testings etc. I think the OP (Peter Mc) reported he could actually hear the difference so I would not rule out audible differences so quickly.

I used Connects for many years and I became unhappy with the sound (digital out) a few years ago without being able to figure out why. This does not prove anything of course so I have decided to purchase an old ZP90 (reported as remaining bit-perfect) and once I get my hands on it I will try a blind test against my recent Connect to see what I find 🙂. It will be a few weeks before I do this but I will report back.


It seems a shame to let this epic thread die, so how did you get on?

I have two CONNECTs, and they sound as good as anything I've ever owned, using either the digital or analog outputs. However, I confess that I listen with my ears and not with a signal analyser.



Unfortunately I never managed to test one against the other :-(. My plan has been derailed / delayed until I find out how to implement some room correction on the connect. I was planning to add a receiver / av processor in order to take advantage of room correction and I fear that the connect will become out of sync with my other zones (if fed through the receiver).
Different conversation and of course widely reported elsewhere.
I was planning to add a receiver / av processor in order to take advantage of room correction and I fear that the connect will become out of sync with my other zones (if fed through the receiver).

Use of room correction DSP takes away much of any supposed merit in bit perfect though? And yes, there will be sync delays but these will matter only when you play all zones as one group and sound from one zone carries across to the others.

I am no fan of trying to keep the source signal in its virginal purity and glory by the way, in the way of many audiophiles; most domestic rooms do enough to sully that virginity quite thoroughly before the sound gets to your ears, and good room response DSP is an important aspect of any audio set up these days. And since the Connect won't do Trueplay, you will have to go another route.
I have indeed accepted that the Connect is no longer bit perfect and I take that for granted now. It does not bother me as much as before because I have adopted Roon alongside Sonos and I have introduced a bit perfect Roon zone to the main system. I still want to use Sonos for the multiroom sync + Ease of use + Spotify integration. Assuming I can achieve this, these are significant advantages which partly balance out the bit-perfect situation (for me).

I find the Roon zone sounds great with no tweaking required but I need to tweak the Connect as I am not very happy with the sound. Multiroom sync is very important for me and sadly I fear this will not be possible once I link the Connect to a DSP unit (such as a Receiver). The only way would be to feed the Connect directly to the power stage of the amplifier but this is taken by the AV Receiver (pre out).

This is another topic however. In terms of the Connect, I have accepted (and take it as granted) that it is not bit perfect and that Sonos does not plan to return to that.
...I have introduced a bit perfect Roon zone to the main system.
What kit did you use for this, please?
...I have introduced a bit perfect Roon zone to the main system.
What kit did you use for this, please?


Hi Amun, I will PM you the details so that I don't take this thread out of topic.
...I have introduced a bit perfect Roon zone to the main system.
What kit did you use for this, please?


Hi Amun, I will PM you the details so that I don't take this thread out of topic.

Many thanks...
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I have indeed accepted that the Connect is no longer bit perfect and I take that for granted now. It does not bother me as much as before because I have adopted Roon alongside Sonos and I have introduced a bit perfect Roon zone to the main system. I still want to use Sonos for the multiroom sync + Ease of use + Spotify integration. Assuming I can achieve this, these are significant advantages which partly balance out the bit-perfect situation (for me).

I find the Roon zone sounds great with no tweaking required but I need to tweak the Connect as I am not very happy with the sound..


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.
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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.

I’ve never witnessed “constant pimping of Roon” here. I doubt that I’ve mentioned it more than handful of times over a few years. And I seldom see others mention it. (I have no connection with Roon, other than being a happy paying customer.) However, I do see other services mentioned far more frequently in all manner of discussions, often where nobody “asks” about them. What’s more, I wasn’t aware that somebody must be “asked” about something before it can be mentioned here. Perhaps because this is your opinion only? So, sincerely, I think you’re way off base. Roon is a product that works very well with Sonos, although that is by no means it’s main focus.
You are the last person who should be criticizing anybody for personal attacks. Your perception of “fanboi” seems a bit overdramatic, particularly since your name was not mentioned in my post. On the other hand, I find posts that say “sigh” in a dismissive manner to be highly insulting. It’s all in the eye of the beholder, I suppose. But thanks for the chuckle.
Sigh. Glad I could give you a laugh! :8