Question

Connect no longer bit-perfect?

Forum|Forum|10 years ago
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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J

JRausch

Lyricist III

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.

K

Kumar

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.

A

amun

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....

K

Kumar

Why am I not surprised that you can't come up with a better response?

E

Emile15

Unless I missed something, there still isn't a reply by Sonos to the original question about the Connects not being bit perfect?

Y

Yiannis74

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.

K

Kumar

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.

Y

Yiannis74

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.

A

amun

...I have introduced a bit perfect Roon zone to the main system.

What kit did you use for this, please?

Y

Yiannis74

...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.

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