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

The 'usual idiots' who request a level-matched double-blind test?

Yes the 'idiots' who would like to see objective scientific evidence rather than believing marketing hype and claims of superhuman hearing or violations of the laws of physics. Those idiots.

The world is truly upside down. Next thing we know, the cast of 'Finding Bigfoot' will get accepted to Mensa.



Just listen to it.

If you can't hear it fair enough. If you can then decide whether it is worth the price.


Been there, done that. If there's a difference, it's going to be in the mastering, definitely not in the rendering. 16/44.1 was chosen for its ability to completely reproduce EXACTLY everything the human ear is capable of hearing. That fact hasn't changed. What has changed is the level of marketing pushing for ever higher bit depths and sampling rates, some of which may be useful on the recording side of things, but meangless in the reproduction chain, except to get technically unsophisticated rubes to purchase music yet again at inflated prices.

BTW, there isn't a recording in existence that uses even the full 16 bits of a CD. Most pop music has ~ 9dB of dynamic range; see "loudness wars". Not many amplifiers have noise floors below the -120dB of a dithered 16 bit recording, either. The extra 8 bits of a 24 bit recording are simply lost in the noise. We won't even talk about the noise floor of a typical living room, and what a full 120dB of dynamic range above that would do to your eardrums, lol.
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Blimey thanks for the education. Christ, tomorrow they will probably tell me the earth isn't flat, that will really ruin my week.

Yeah, of course it is in the mastering, but when the best masters are only available through hi res or MQA it would be nice to be able to play them.

I agree with what you said, but I think there is lots to be done with timing and reducing digital smearing, and that is usually done at higher rates.

If all dacs were perfect, if all masterings were perfect your arguments would hold true, but they are not. Still a long way to go.


Have you tried MQA?
A simple MQA dac and a pair of headphones, switch the MQA on and off. Some tracks have serious gains, others not so.
But there is a difference.


However, no matter what I say you obviously have your beliefs and don't want to change them.
I don't deal with "beliefs". That's for the audiophools. I stick to facts. Real facts, not alternative ones.
I think 44.1kHz is good enough if the DAC does it's job properly. But there may be filtering, phase, leakage and non-linearity issues that make a real-world DAC less than perfect at 44.1kHz. The Sonos DAC is mid-range at best.

There are arguments you can make for 24 bit (and Sonos have said this themselves). The least-significant of 16 bits buys you a noise floor of -90dB (ignoring dithering, which is what gets you to the quoted -96dB of CDs). The next bit gets you to -84dB, so there is a 6dB difference, which is generally agreed to be audible at normal volume. It's not clear if this matters at such low volumes. At the other end of the scale, the volume difference between the two most significant bits is about 0.0003dB, so this is unlikely to be an issue.

It is likely that the mastering of hi-res and MQA songs is the biggest difference here. It would be interesting to downsample one of these and do an ABX test.

All Sonos kit uses a 1dB brick-wall limiter, which you could probably argue is at least as big a problem as resolution and bit rate.

Cheers, Peter.

The point is, as a Sonos customer where do I go from here?

Lol. How about to listening to more music?
Peter, the only way one can rank the Sonos DAC against any other at any price on sound quality is via a level matched blind test, and I am yet to see one reported any where. If I do, I just might have reasons to reconsider what my ears tell me today!
Obviously, in the case of DACs with bolted on filters and additional EQ capability there will be a better ability to customise sound to preferences/room responses, but that is then no longer just a DAC comparison if one is comparing one of these with another.
I could just as well claim sound signatures from power supply units, as some audiophiles still do by the way. And if the Connect had an ability to accept an external "audiophile quality" PSU as an option, people would be claiming better sound from using these! Why do you think does the DAC question not raise its head in the world of pro audio where active speakers with built in DACs generally are the norm? Because DACs have now matured to the level of PSUs and have become commodity components that it does not take special skills to integrate into an an amp, or an active speaker. As in the case of PSUs, it just takes sound engineering that is no longer cutting edge and therefore is widely known. There will still be cases of lousy implementation of DACs, but that is also in the case of PSUs.
On audiophiles, a question: why can't someone that has a 1 pair/5 pair with bonded Sub, properly set up in a room, Trueplay tuned,using the best available masters, also be called an audiophile?
Answer: Because his kit has tone controls:D
As an aside, my most extreme audiophile dabbling was in adding a Tube buffer between my preamp and amp, a little box of tricks made by Musical Fideiity in the UK. The idea sold, that I too bought mindlessly, was that it would add the tube magic to my sound.

Now, that box also was sold with an optional box of the same size and looks, that was just an auxiliary PSU, that bypassed the built in PSU in the buffer box, to take the sound to the next level of "where do we go from here". I bought that as well.

Finally, and I still cringe to say this, I bought a purple coloured, thick as my finger, 6 inch long umbilical cord to connect the PSU box to the Tube Buffer box. THAT was to take the whole magic to the ultimate level. It was made in California, if that is saying something about it:D

Never Never Land of fairy dust. The magic mushrooms were all that were missing.
if all masterings were perfect
Now if someone could make a box of tricks that would let the mastering quality be irrelevant, by extracting the "true" sound from every mastering, THAT would be ground breaking progress. As an option of course, that sound may not be to everyone's tastes.
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I don't deal with "beliefs". That's for the audiophools. I stick to facts. Real facts, not alternative ones.

So you won't even listen to other kit? It is a blanket 'fact' that all kit sounds the same?

You don't think each manufacturers kit has their own sonic signature?

OK. Fair enough.
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The point is, as a Sonos customer where do I go from here?

Lol. How about to listening to more music?


I listen to music all day. But I do agree with the sentiment.



Obviously, in the case of DACs with bolted on filters and additional EQ capability there will be a better ability to customise sound to preferences/room responses, but that is then no longer just a DAC comparison if one is comparing one of these with another.


But that is what separates a good DAC from an average DAC.

You used to get the one filer, the one the manufacturer thought was best, now you get an option between different types so you can choose the sound you like.
What is so wrong with that?

Plus apodising, MQA decoding etc. etc.

Anyone who says all DACs are the same just sounds extremely ignorant.
What's wrong with that is you can do the exact same thing with a DSP and/or equalizer, in an almost infinite amount of configurations, and not pay thousands of dollars for it. A DAC shouldn't be purposefully coloring the output, if it does, it is not a "pure" DAC, it's nothing but DSP snake oil easily achieved in much less deceptive (and less expensive) ways.
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What's wrong with that is you can do the exact same thing with a DSP and/or equalizer, in an almost infinite amount of configurations, and not pay thousands of dollars for it. A DAC shouldn't be purposefully coloring the output, if it does, it is not a "pure" DAC, it's nothing but DSP snake oil easily achieved in much less deceptive (and less expensive) ways.

You can tailor the sound to make it sound similar using DSP, but that will be hiding more detail. Not saying that is a bad thing.
And there has been advances in digital playback that has improved things considerably, to believe that we can progress no more is just naive.
I agree a DAC shouldn't colour the output, but they are not perfect yet, so they do, the better DACs simply colour them less.


Who has said anything about paying thousands of dollars?
I am talking about DACs like the Meridian Explorer 2, retails at £129 (so around $149) or the Audioquest Dragonfly at £89, so around $119, both will do MQA.

I use Roon a my interface, Sonos as the endpoint is nice because it allows me to also play the compressed services Roon does not support like Spotify and Apple Music, so it is handy. What is wrong with wanting to be able to play the MQA files?

Why do the same people feel the need to come into every thread where people are asking for new features or for devices to be bit perfect and say "You're wrong, you're an idiot, all hifi and all files sound the same."

Do you go onto Porsche forums and say "You're all stupid, a Toyota will get you from A-B" or the watch forums and say "A Casio from the filling station free with a tank of gas will tell the time the same as a Rolex".
Of course they will, but some people may want more than that.

Peter, the only way one can rank the Sonos DAC against any other at any price on sound quality is via a level matched blind test, and I am yet to see one reported any where. If I do, I just might have reasons to reconsider what my ears tell me today!


Is what your ears tell you today the result of a level matched blind test?

I think it is important that we apply the same standards to ourselves as we require of others. I admit I do not always live up to this - it's difficult, requires constant vigilance, and an occasional reminder from friends 🙂


Why do the same people feel the need to come into every thread where people are asking for new features or for devices to be bit perfect and say "You're wrong, you're an idiot, all hifi and all files sound the same."

Do you go onto Porsche forums and say "You're all stupid, a Toyota will get you from A-B" or the watch forums and say "A Casio from the filling station free with a tank of gas will tell the time the same as a Rolex".
Of course they will, but some people may want more than that.


A Porsche can be objectively tested against a Toyota using scientifically valid methods and found to be a better performer. Also, if a Toyota was measured 0-60 to be faster than a Porsche (it has happened) in an objective series of tests, would you actually claim the Porsche is faster 0-60? Bottom line, give me a scientifically valid objective test of differences in quality of audio equipment and I'll back your post against any and all comers.

I'll be waiting.

As to the Rolex vs. Casio analogy, if you want to purchase audio equipment according to subjective styling or expensive decorative jewels or other materials, be my guest. I do the same with lots of purchases. However, if you claim it performs better, you better have experimental data to back up that claim.


Is what your ears tell you today the result of a level matched blind test?

I carried out an extensive one in 2011 using the Connect in analog mode and while using it to feed the digital inputs of my highish end Marantz SACD/KI Signature labelled player. In this set up, blind protocols were observed. Level matching was not done by instruments, but I don't think it was needed given the nature of the two inputs and the use of the exact same master/recording - which was Kind of Blue and Something Else, by the way. While switching back and forth, only the input selector on the SACD player was used and volume controls on the Connect or the downstream Quad 99/909 amp were not touched. Speakers used were Harbeth C7s, in the near field. But even if instrument based level matching was missing, here is my thinking on that subject - if I did not hear any differences even so, I do not see that I would have heard differences after instrument based level matching.

I confess that I haven't carried out a test on every DAC pair out there. I don't think I need to do that.

On the subject of DACs in general, a DAC is supposed to be a HiFi component in the sense of having to be audibly true to the original signal. Coloring isn't its function and DACs these days don't do this. Or so I have found.

DSP of different kinds is a different subject, and should not be used to muddy the waters of DAC quality assessments. One could just as well do this for a PSU comparison!
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Why do the same people feel the need to come into every thread where people are asking for new features or for devices to be bit perfect and say "You're wrong, you're an idiot, all hifi and all files sound the same."

Do you go onto Porsche forums and say "You're all stupid, a Toyota will get you from A-B" or the watch forums and say "A Casio from the filling station free with a tank of gas will tell the time the same as a Rolex".
Of course they will, but some people may want more than that.


A Porsche can be objectively tested against a Toyota using scientifically valid methods and found to be a better performer. Also, if a Toyota was measured 0-60 to be faster than a Porsche (it has happened) in an objective series of tests, would you actually claim the Porsche is faster 0-60? Bottom line, give me a scientifically valid objective test of differences in quality of audio equipment and I'll back your post against any and all comers.

I'll be waiting.

As to the Rolex vs. Casio analogy, if you want to purchase audio equipment according to subjective styling or expensive decorative jewels or other materials, be my guest. I do the same with lots of purchases. However, if you claim it performs better, you better have experimental data to back up that claim.


I give up.

You really are missing the point.

Some people want to discuss these things, let them discuss it rather than come into the thread and derail it.

The analogy with the car was not comparing dac differences FFS! It was pointing out on every forum, no matter what the subject content is, you get silly know it all old men like yourself who ruin every thread like you guys have this one. What pleasure do you get from that?
If you don't agree with our point of view fair enough, but just keep out and let people discuss things.
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Is what your ears tell you today the result of a level matched blind test?

I carried out an extensive one in 2011 using the Connect in analog mode and while using it to feed the digital inputs of my highish end Marantz SACD/KI Signature labelled player. In this set up, blind protocols were observed. Level matching was not done by instruments, but I don't think it was needed given the nature of the two inputs and the use of the exact same master/recording - which was Kind of Blue and Something Else, by the way. While switching back and forth, only the input selector on the SACD player was used and volume controls on the Connect or the downstream Quad 99/909 amp were not touched. Speakers used were Harbeth C7s, in the near field. But even if instrument based level matching was missing, here is my thinking on that subject - if I did not hear any differences even so, I do not see that I would have heard differences after instrument based level matching.

I confess that I haven't carried out a test on every DAC pair out there. I don't think I need to do that.

On the subject of DACs in general, a DAC is supposed to be a HiFi component in the sense of having to be audibly true to the original signal. Coloring isn't its function and DACs these days don't do this. Or so I have found.

DSP of different kinds is a different subject, and should not be used to muddy the waters of DAC quality assessments. One could just as well do this for a PSU comparison!



Simple question...

Do you believe digital audio has reached perfection?
K
I give up.

You really are missing the point.

Some people want to discuss these things, let them discuss it rather than come into the thread and derail it.

The analogy with the car was not comparing dac differences FFS! It was pointing out on every forum, no matter what the subject content is, you get silly know it all old men like yourself who ruin every thread like you guys have this one. What pleasure do you get from that?
If you don't agree with our point of view fair enough, but just keep out and let people discuss things.


Sorry, but I'll not sit back and let people post unscientific, subjective nonsense, nor will I let you bully me into stopping my replies. If you don't like my posts, disprove them. Humiliate me with facts and knowledge and I will shut up. Until you do, I will post what I want, when I want, as long as I'm within the forum TOS. I've not asked you to stop posting just because you disagree with me, have the same amount of respect for me.

And by the way, when you have to stoop to childish attacks like "silly know it all old men" when you don't even know my age, you've already lost the argument. Good job derailing the discussion into personal jabs. That's on you, not me.

PS- What are you talking about with "our point of view?" Last time I checked, the only person preaching the subjectivist/audiophile point of view is you. So by your rules, we should be the ones running you out of the thread, (except we don't do that).

You can tailor the sound to make it sound similar using DSP, but that will be hiding more detail.
I agree a DAC shouldn't colour the output, but they are not perfect yet, so they do, the better DACs simply colour them less.

Why do the same people feel the need to come into every thread where people are asking for new features or for devices to be bit perfect and say "You're wrong, you're an idiot, all hifi and all files sound the same."

Do you go onto Porsche forums and say "You're all stupid, a Toyota will get you from A-B" or the watch forums and say "A Casio from the filling station free with a tank of gas will tell the time the same as a Rolex".
Of course they will, but some people may want more than that.

Interesting statements, that allow for responses!
1. Room response DSP emphasises a particular detail over another and does this to compensate for the way room responses have messed up with the existing detail; so it isn't hiding any detail in an absolute sense, but restoring what was lost on the way from the speakers to the ears. It isn't perfect, but that is the direction of progress.
2. DACs may have bolted on DSP to colour the sound and that is by design. Nothing wrong with that as long as the DAC also has a flat mode such that one doesn't have to hear sound of a particular colour all the time. And in flat mode, DACs should and nowadays usually do, sound the same to the extent that is audible. Anyone saying that one DAC colours sound less than another in flat mode needs to have some basis other than subjective experience of the usually quoted kind to offer coherent responses when challenged. On this subject, if you were to say that the Connect has limitations because of its limited EQ capability and using a better equaliser downstream of it would give better results, I would not argue - but I would expect even that device to be just a pass through in flat mode, an essential feature.
3. Because people keep saying inaccurate things like saying that what some of us say includes things like: " All Hifi and all files sound the same". It doesn't and they do not.
4. In a Porsche forum, I would not tout the benefits of Toyota as you suggest I would. Because I would expect all forum members to have accepted that in buying a Porsche, they have willingly given up some admitted benefits of Toyota, so saying this would be wasting everyone's time. Where the analogy collapses is when you say that in buying Sonos, I have given up such and such sound quality benefits compared to XYZ. That may well be the case, but not in every case that is brought up here. In fact, there are very few cases where this is found to have an objective basis.

People that use Rolex do not ever claim - now - that it is for superior timekeeping. One does not even need a watch now, the smart phone does it all for me on that front, with unfailing accuracy as long as I charge the bloody thing! But those that wear Rolex, do so to flaunt wealth and status and don't hide that - do you know anyone that uses a Rolex that no one else can see?! They want something from Rolex other than - as you have also pointed out - time keeping that is superior to a Casio. But bringing the analogy home, people aren't willing to admit that their new audio kit is bought for more than just better sound. Why not be honest about it as the Rolex owners are? Why also beat the better time keeping/sound quality drum? If you want something more and it floats your boat - say something like backlit dancing VU meters for each channel - say so as a Rolex owner would!

Simple question...

Do you believe digital audio has reached perfection?

Simple answer: No.

I give up.


About time. Thanks. 🆒

Simple question...

Do you believe digital audio has reached perfection?

Simple answer: No.


Another simple question....


Do you believe digital audio, outside of mastering/production techniques, can be improved by playback resolutions greater than 16/44.1?


Another simple question....


Lol. You are baiting him!
This brings to mind a DAC I once had, made by Musical Fidelity - UK, not So Cal! It was bigger in every dimension than the standard stereo amp, and it weighed about twice as much. Massive heat sinks at the sides because the output stage had a couple of valves - Mil spec ones. It had feet that glowed - the colour changed from blue to red to indicate warm up complete!
It also had a selector for sampling frequency options with an LED indicator for chosen selection that read 24/96 or 24/192. No prizes for what sounded better when one noticed what the read out said.
It cost me about GBP1000. I ended up gifting it to a friend; I did not have the integrity levels needed to sell the beast to him. He was thrilled beyond measure, so someone is getting value from it, which is good.
The DACs I now use are sitting somewhere inside in my play 1 units/Connect Amps along with all the other good stuff:D
It's a simple question that deserves it's own thread. I'll start one.
Good idea Peter; name it well!
Actually Kumar, the question was for you. I wanted clarification on your 'No' answer to the previous answer (which i agree with).

I already know what his answer is. 😉