Can digital audio playback be improved by resolutions greater than 16/44.1?

Here is a Sep 2015 view on the subject from Sonos:
Sonos only supports up to CD quality, while others are capable of playing back 24-bit tracks. Giles Martin, sound leader at Sonos, claims this shouldn't make a difference though.

"You can't upscale audio, it doesn't work so it becomes a numbers game…I can make a call to shift us [to 24-bit], it isn't hard, but the problem is on the experiential side, it has to be right. You have to make sure things don't drop out or stop. Even with Tidal we are on the edge right now because the pipe needs to get bigger."

Martin added: "I refuse and the company refuses to play this numbers game where you go 'we're better than you', 'how much better', 'we are 8 better than you'. It doesn't make any sense as far as the consumer stuff goes and I think that's where we are at right now. I think it would be great if people listened to CDs right now and then say 'you know what, we need a bit more' and then they can experience it if they want and decide whether they can hear the difference or not as most people can’t."

And, if you read the often quoted xiph.org material on the subject, 24 bit for listening isn't even preferred to 16 bit, it just isn't necessary, and therefore a wasted resource.

A quoted part from that site:
"Professionals use 24 bit samples in recording and production for headroom, noise floor, and convenience reasons.

16 bits is enough to span the real hearing range with room to spare. It does not span the entire possible signal range of audio equipment. The primary reason to use 24 bits when recording is to prevent mistakes; rather than being careful to center 16 bit recording-- risking clipping if you guess too high and adding noise if you guess too low-- 24 bits allows an operator to set an approximate level and not worry too much about it. Missing the optimal gain setting by a few bits has no consequences, and effects that dynamically compress the recorded range have a deep floor to work with.

An engineer also requires more than 16 bits during mixing and mastering. Modern work flows may involve literally thousands of effects and operations. The quantization noise and noise floor of a 16 bit sample may be undetectable during playback, but multiplying that noise by a few thousand times eventually becomes noticeable. 24 bits keeps the accumulated noise at a very low level. Once the music is ready to distribute, there's no reason to keep more than 16 bits."

For why there is no reason, see the material on the site and see if it convinces you:) - dither is addressed.

All I know about 24 bit recordings is from my excellently produced and noticeably more expensive 24 bit recorded CDs from JVC, marketed as XRCDs - Xtra Range. Very good packaging, liner notes and mastering. But no better than the best CDs from other production houses for sound quality. They now sit in my NAS and sound just as good as they did when played through a high end SACD player with a pure copper chassis(sic), wired to a pre amp + amp, wired in turn to very good passive speakers, via thick speaker cables. But in place of all those boxes and messy wires and a component rack is a well placed 1 pair + Sub, tuned to the room via Trueplay. The racks of CDs are gone, into a NAS that isn't to be seen.

This is digital audio at its best. Will it be improved? Of course - via better active speakers and better versions of Trueplay. Hopefully there is also still some scope for Sonos to further improve the sound quality from the existing hardware, improvements delivered free over the net, all the way from the US to India.

This to my mind is real progress, not to be shied from. IMO, it is close to magic. All that is missing is the glow of the valves:D.

Peter, more from xiph for you to ponder and/or research:
"16 bit audio can go considerably deeper than 96dB. With use of shaped dither, which moves quantization noise energy into frequencies where it's harder to hear, the effective dynamic range of 16 bit audio reaches 120dB in practice [13], more than fifteen times deeper than the 96dB claim.
16 bits is enough to store all we can hear, and will be enough forever."

So not just dither, but shaped dither!

Thanks Kumar. That is fascinating - I never realized dither could increase the dynamic range that much. Having thought about it for a bit, I now understand how this works. It's interesting that Monty's plot cuts off at about 10kHz. I got to wondering what happens beyond that, and also what happens if there is more than one frequency? So here is an extended version of his plot. You can see the noise is shifted to frequencies that most of us can't hear, but those with excellent/young hearing might perceive increased very-high-frequency noise. Multiple frequencies increases the noise level slightly (see here), so real music with all frequencies present might increase this further.

So, based on this, I still contend that if dithering is necessary, it would be preferable to use more bits and not add potentially audible noise. I concede this is all really low level stuff.

Cheers, Peter.

Here is a recent scientific paper that gathers together many reputable high-res audio tests in a meta-analysis. The main conclusions (taken from the abstract) are:

"Results showed a small but statistically significant ability of test subjects to discriminate high resolution content, and this effect increased dramatically when test subjects received extensive training."

"The overall conclusion is that the perceived fidelity of an audio recording and playback chain can be affected by operating beyond conventional levels."

A careful reading will reveal that the author makes no finding about the causes of this result. However, it is also mentioned that most of the contributing studies varied the sample rate, not the bit depth. (See section 4.1 for these two statements).

Already discussed. Notice there is purposefully no mention of quality differences in the meta-analysis, only "differences". This slight significance can easily be explained by the presence of intermodulation distortion in the playback hardware caused by the stresses of reproducing ultra-sonics. This distortion has been tested to be audible, and unfortunately for the misleading commentary of the meta-analysis, it is always harmful to the quality of the sound.

Already discussed.
Where?

This slight significance can easily be explained by the presence of intermodulation distortion...
Intermodulation distortion was identified as a potential bias in three studies that, as far as I can see, were not used in the meta-analysis. See Table 2B and the second last para of section 2.4. Studies 25, 60 and 61 do not appear in Table 2.

I can make a call to shift us [to 24-bit], it isn't hard, but the problem is on the experiential side, it has to be right. You have to make sure things don't drop out or stop. Even with Tidal we are on the edge right now because the pipe needs to get bigger."

So he's saying that Sonos could shift to 24-bit, but then they would have trouble guaranteeing their current reliablity. They know this as Tidal is putting their technology 'on the edge right now'. Perfectly logical, given the much large file sizes involved.

It doesn't make any sense as far as the consumer stuff goes and I think that's where we are at right now.

So he's not even saying that there isn't a difference, just that it doesn't matter to consumers - in particular, potential Sonos customers, which is what they'll be mainly concerned about.

Many here have said that if a hi res file is down sampled to a Sonos compatible format and played on Sonos front ended kit, it cannot be audibly distinguished from where the file is being played in the native format via hi res capable kit, all other things like the speakers in use being the same.

Surely the test should be on the same (HiRes capable) player. There might have been an argument when the 'bit-perfect' argument was valid, but surely not on modern Connects.