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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Ryan S

Retired Sonos Staff

I would say calling someone out publically on the community as "the reason people don't come here" is a personal attack, don't you agree? Even if you don't, I think we can all agree that it has nothing to do with the conversation around the CONNECT"s audio playback abilties in this ~440 reply thread. I'd be happy to discuss this in private if you'd like, but for the sake of everyone who keeps coming to this thread due to getting email updates, let's stay on topic.

As to the thread you posted, if you're still having that issue, I'd say it's best to give us a call on our support line and work with a technician on it. It'd be easier to figure out what "distortion" means, and determine if it's due to a hardware issue or something else.

Mark good posts by pressing the like button, and select the best answer on questions you've asked to help others find solutions.

chicks

Tunesmap looks far more interesting than Roon. It’s clearly being marketed to music lovers, while Roon seems more oriented to the delusional audiophile tweakers. Naturally, it will require Sonos.

https://mobile.nytimes.com/2017/09/29/business/media/tunesmap-liner-notes.html

Belly M

Tunesmap looks far more interesting than Roon. It’s clearly being marketed to music lovers, while Roon seems more oriented to the delusional audiophile tweakers. Naturally, it will require Sonos.

https://mobile.nytimes.com/2017/09/29/business/media/tunesmap-liner-notes.html

Missed this, very interesting thanks chicks.

R

River__s

Contributor I

For this mean the original circa 2010 zp90 commands a higher resale value?? ?

K

Kumar

I would not buy one for a higher price - but you can try your luck to see if you can find an audiophile that believes.

MikeV

Unless the refresh of the Sonos Connect - a new Connect appeared in the FCC database back in April last year - happens to also have a return to bit-perfect?

The known difference between this new Connect and any existing versions is the wireless card... which is what would have required updated FCC records. Other changes could have been made as well. Whether this new Connect is even available yet is unknown.

The S in IOT stands for Security.

K

Kumar

I was referring only to paying a higher price for a 2010 made zp90 as opposed to say, a 2017 made Connect, in the used market - something I would not even dream of doing if I was in the market as a buyer. A brand new model Connect would of course be evaluated on other features as well, to decide a buy at the price asked.

G

Gadgetgeek

Contributor I

I doubt there is any other change beyond volume normalisation, and this can be defeated on your own collection by removing any volume normalisation tags if you really don't want it.

Note that you can't remove tags from music from streaming services.

So, the sky isn't falling in for most people as there are workarounds. It is, however (IMO) clumsy of Sonos to require people to have to use those workarounds.

It would also be much better if Sonos actually implemented a complete solution for volume normalisation as most people would be happy with having it, if it worked properly. The complaint here is that the Sonos implementation of volume normalisation is partly broken and there is no easy way to disable it.

Cheers,

Keith

G

Gadgetgeek

Contributor I

I've been following a few of these threads over the past several years. I also use a Connect, and have it connected to an Arcam D33 DAC.

It would definitely be beneficial if Sonos implemented a "defeat" switch for the Normalization process. But based on their target market for these products and the fact that people are streaming from the "cloud" it prob won't occur.

I made sure that I did not use any software that added ID3 Normalization tags. Seems to be a simple solution if you are somebody that is so concerned about audio quality.

B

basd2

Lyricist I

Any chance this will get resolved?

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