"The Beginner’s Guide to Hi-Res Audio"

  • 7 December 2021
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https://web.archive.org/web/20100410235208/http://www.cs.ucc.ie/~ianp/CS2511/HAP.html

“...Localization accuracy is 1 degree for sources in front of the listener and 15 degrees for sources to the sides. Humans can discern interaural time differences of 10 microseconds or less.”

https://www.ece.ucdavis.edu/cipic/spatial-sound/tutorial/psychoacoustics-of-spatial-hearing/#azimuth

“...under optimum conditions, much greater accuracy (on the order of 1°) is possible...This is rather remarkable, since it means that a change in arrival time of as little as 10 microseconds is perceptible. (For comparison, the sampling rate for audio CD’s is 44.1 kHz, which corresponds to a sampling interval of 22.7 microseconds. Thus, in some circumstances, less than a one-sample delay is perceptible.)”

 

You (and that paper) have a fundamental misunderstanding of what sample rate means and how it applies to digital sampling.  A change in arrival time of 10 microseconds due to positioning has no relationship to digital sample rate.  There is no “gap” in the data in which a phase shift can be missed because 10 microseconds is less than ½ sample rate. 

How, you say?  Well, as shown by Nyquist-Shannon, a bandwidth limited digital audio file converted back to analog doesn’t have gaps or stair steps or any of the other silly representations, it is actually EXACTLY the same as the original analog signal as captured by the listening device. 

Let’s say this again: Within ½ the bandwidth limit, there is no data loss, none.  Therefore, at 44.1 kHz, all audible sound is reproduced exactly as it was in analog form, and the ear hears all of it, including the phase shift.  All increasing the bandwidth would do is increase the frequencies that are reproduced, and the ear doesn’t hear ANYTHING over 20 kHz, phase shifted or not.

 

So read my Google Fu:

Strictly speaking, the theorem only applies to a class of mathematical functions having a Fourier transform that is zero outside of a finite region of frequencies. Intuitively we expect that when one reduces a continuous function to a discrete sequence and interpolates back to a continuous function, the fidelity of the result depends on the density (or sample rate) of the original samples. The sampling theorem introduces the concept of a sample rate that is sufficient for perfect fidelity for the class of functions that are band-limited to a given bandwidth, such that no actual information is lost in the sampling process. It expresses the sufficient sample rate in terms of the bandwidth for the class of functions. The theorem also leads to a formula for perfectly reconstructing the original continuous-time function from the samples.

 

https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem

 

You fell for the old audiophile nonsense that there are “gaps” in the data because each sample is a “slice in time”.  It’s just not true.  Sampling isn’t slicing the data, it is transforming the data, ALL of the data, into a format that can be stored digitally.  The digital to analog step then transforms the data, ALL of the data, back to it’s original analog form.  Nothing is lost, phase shifted or not. 

 

You need trained ears and a $50,000 system!

I can guarantee that in my home, even late at night, no human, however trained, will be able to pick the difference in a blind listening test even on a USD 100,000 system. Because that still has to deliver sound after interacting with my room - with its acoustics and ambient sound levels - which is a typical domestic one.

Whereas the HD video I can pick on a cheap HD capable TV, even when I have left my glasses out of reach.

HD audio is just digital snake oil, consumed by the credulous, who need the HD mark to be visible on their player/app to even know that they are listening to HD audio. 

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@ Kumar. I think we are just seeking an additional data point to make sure that it is working. Otherwise, your point is sensible.

It makes me wonder if there was a certain amount of “everyone else is doing it, we’ll lose sales if we don’t too” in the decision.Sometimes, being the lone voice of reason in the wilderness isn’t the ideal position to be in when you’re trying to sell stuff. Of course, other times, it’s the perfect thing...so who knows? 

 

Some say in some circumstances, that they can hear a difference between HD (16-bit) audio and UltraHD (24-bit) audio.. I’m not one of those people. I have been quite happy in the past with the lesser 320 AAC lossy audio.

Anything can be said, but no one has even claimed to have picked this difference in a controlled level matched blind listening test, using the same source file in the 16 bit version and comparing that with the 24 bit version. Not even on the most accurate headphones, which may perhaps be able to pick the difference between 16 bit and lossy 320 - in even a quiet domestic environment using the best/most expensive speakers out there, this too has not been demonstrated, room acoustics will come in the way.

Perhaps this is all pickable if the tester is the being in the HMV logo of many years ago...with training!

On the other hand, the psychological reasons for hearing all kinds of differences are well known and not just in the world of home audio. And of course, where sound levels are not accurately matched between the alternatives, the reason isn't even psychological.

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Does the generation 2 of the sub support Amazon Music high res 24 bit audio? I do not see anything about the compatibility of the subs. I did the update on the app and currently I am only seeing HD and no Ultra HD song tags (which I know are UHD). My current set up uses two fives with a gen 2 sub. Thanks. 

From the article:

As of this post’s publish date, the following Sonos products are capable of playing 24-bit music at 48 kHz: RoamArcBeam (both generations), FiveSub (all generations)MoveOneOne SLPortAmp, SYMFONISK Bookshelf, SYMFONISK Table Lamp, Play:5 (Gen 2), Connect (Gen 2), and Connect:Amp (Gen 2).

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I guess it’s a case that people want to know that they are getting the quality of audio they are paying for. Whether it’s actually needed, or not, becomes a separate question. 

 

Pretty much, this ^. That is all. And as a psychologist, lectures about psychology are even further drivel to my ears, or eyes.

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I thought the blog was very open about the advantages of hi-res. Though explained within the (commercial) restraints (you would not want to bash this new feature) it does state CD-quality contains all you can hear. Hi-res is just because that's the way music is recorded and because it can be done. No claims about quality anywhere.

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Does the generation 2 of the sub support Amazon Music high res 24 bit audio? I do not see anything about the compatibility of the subs. I did the update on the app and currently I am only seeing HD and no Ultra HD song tags (which I know are UHD). My current set up uses two fives with a gen 2 sub. Thanks. 


Having a similar issue but with Ones and Sub gen 2. When the sub is bonded, only HD plays. If I remove the sub so the Ones are in a stereo pair, Ultra HD will play. Rebond the Sub and it drops back to HD for the same songs that were just playing in UHD.

My Arc is bonded with Play:3 surrounds and a Sub gen 2 and I’m able to play Dolby Atmos/Ultra HD on that setup without any issue.

The bigger net thing is the biggest crock I've ever seen in print.  The 16 bit "net" is already big enough to record a mosquito in the room followed by a jack hammer.  How big a net do you need? 

 

But 24 bit is used in studio recordings, right?  Might of been better for the article just to leave that issue alone and just state what is done without going into why it’s done that way.

One other thing I didn’t like about the article is it seems to conflate recording in a studio with the final produced file coming out of a studio.  There is no doubt that what’s recorded is mixed and mashed up to remove issues and mistakes, staple together the best parts of multiple records, etc.  You aren’t really getting a perfect reproduction of what was recorded in the studio regardless of what resolution of audio you’re listening to.

 

The other place Sonos is being disingenuous is in equating Sonos speakers with quality headphones as being able to be like the recording studio such that this new super fantastic sound quality can be heard. Like ALL other speakers that interact with the room acoustics and have to deal with the ambient sound levels in even a quiet domestic room, Sonos speakers can never do what headphones can - eliminate the room and all that it brings to the listening, from the frame.

 

Quality is a subjective term, and I don’t fault Sonos in this regard for using it.  Personally, headphones don’t feel as natural to me, and the lack of external sounds, or having muffled external sounds, can be more distracting.   And obviously, headphones lack the shared experienced with others and prevent communication, etc.  I get what your saying regarding ambient noises reflections, but they are a part of reality, and certainly what you would get if you were listening to a live performance.  Removing everything but the music is different, not necessarily better.  Headphones most certainly have their place and are great for some people and situations,  but are certainly not an objectively better option than speakers .

 

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The other place Sonos is being disingenuous is in equating Sonos speakers with quality headphones as being able to be like the recording studio such that this new super fantastic sound quality can be heard. Like ALL other speakers that interact with the room acoustics and have to deal with the ambient sound levels in even a quiet domestic room, Sonos speakers can never do what headphones can - eliminate the room and all that it brings to the listening, from the frame.

Quite true, but nor can headphones create bass that one can feel as well as hear.

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Why can’t the music industry standardize these designations and require compliance. Not sure who or how it would be done, just want transparency and honesty not marketing speak. 

 

Headphones most certainly have their place and are great for some people and situations,  but are certainly not an objectively better option than speakers .

 

I did not say they are better; I just said that they can capture more of what Sonos is talking about and there is therefore a greater chance of this more accurate sound capture being heard on headphones compared to any speaker including Sonos. Not that there is any controlled blind test on headphones that establishes this for Hi Res...but I can see that they have a better chance of picking up any benefit, if  it exists.

Personally I don't like headphones and never use them, but there is little argument against the fact they offer a more accurate sound. The ambient sounds that you refer to are heard on them as well; those in the live performance, be it in a studio or concert hall.  What they eliminate, and what speakers cannot, is ambient sound in your home or mine, or in any other domestic environment. We may like the latter because we are used to it, which makes it just a personal preference.

Because it worked so well with the CEC consortium, and the various issues many manufacturers have had implementing that?

I get where you’re coming from, and support it, but getting various companies to pay attention to a “standard” as opposed to their own bottom line, and marketing strategies seems like a false hope. 

 

Headphones most certainly have their place and are great for some people and situations,  but are certainly not an objectively better option than speakers .

 

I did not say they are better; I just said that they can capture more of what Sonos is talking about and there is therefore a greater chance of this more accurate sound capture being heard on headphones compared to any speaker including Sonos. Not that there is any controlled blind test on headphones that establishes this for Hi Res...but I can see that they have a better chance of picking up any benefit, if  it exists.

 

 

I assume you were referring to the following statement.

However, if you’re listening to a hi-res track with quality headphones or a Sonos speaker, you’re setting yourself up with the best possible circumstances to experience that track as it sounded in the recording studio.

It’s probably intentionally vague, I think, as Sonos can’t really say that 24 bit is better.  Again, I think the statement is silly as it implies nothing is done to the track between it’s recording and the final production file you’re hearing.  But regardless, I think the point was about producing the audio rather than eliminating any other audio you may hear.

Honestly, I think it’s odd that they mention headphones at all, particular since they don’t mention quality speakers that Sonos doesn’t make.  My guess is that the only reason they mention headphones is Sonos is very likely to sell their own headphones very soon.

 

Personally I don't like headphones and never use them, but there is little argument against the fact they offer a more accurate sound. The ambient sounds that you refer to are heard on them as well; those in the live performance, be it in a studio or concert hall.  

 

 

No, I was referring to ambient noises in the actual listening environment, not on the recording.  I personally don’t care for recorded ambient noises, such as you would get in a live recording.  

 

What they eliminate, and what speakers cannot, is ambient sound in your home or mine, or in any other domestic environment. We may like the latter because we are used to it, which makes it just a personal preference.

 

Right, I generally don’t want those eliminated, personally preference.  I use headphones mostly at work, when I cannot use speakers.  The other time I would use headphones is when I need hearing protection or trying to block out annoying sound.

Does the generation 2 of the sub support Amazon Music high res 24 bit audio? I do not see anything about the compatibility of the subs. I did the update on the app and currently I am only seeing HD and no Ultra HD song tags (which I know are UHD). My current set up uses two fives with a gen 2 sub. Thanks. 


Having a similar issue but with Ones and Sub gen 2. When the sub is bonded, only HD plays. If I remove the sub so the Ones are in a stereo pair, Ultra HD will play. Rebond the Sub and it drops back to HD for the same songs that were just playing in UHD.

My Arc is bonded with Play:3 surrounds and a Sub gen 2 and I’m able to play Dolby Atmos/Ultra HD on that setup without any issue.

It would appear that there is an issue with the sub and a stereo pair of speakers playing the UHD files. I have seen this discussion here and in other forums as well. 

 

I get where you’re coming from, and support it, but getting various companies to pay attention to a “standard” as opposed to their own bottom line, and marketing strategies seems like a false hope. 

Won’t work probably because it is snake oil to start with, in terms of what is audible about it. As opposed to the HD and beyond video side of things where there is a universally adopted standard definition for things like HD Ready, HD, 4K etc,

Agreed, Kumar, but even an agreement on the nature of the snake oil nostrum might benefit folks who look for these false “key words” in marketing statement might ease some of the posts we deal with. 

In a broader context home audio is a mess anyway where definitions are concerned - HiFi and Audiophile quality as two classic examples. So in that tradition even someone like Amazon plays fast and loose with the definition of HD, applying it to the CD format. And if I am not mistaken, Sonos has also jumped on that HD bandwagon thereafter.

PS: And of course, the total mess over definition of output power in watts ranging from rms to PMPO...that one is a doozy.

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In the US we have had some regulation of the audio amplifier power rating since 1974. This is a look at the rule and the problems.

[quote]Many manufacturers have taken advantage of this vacuum by publishing a confusing array of unrealistic power claims. Some go so far as to slap a sticker on the front panel with an inflated power figure that's based on only one-channel driven at 6-ohms and 10% THD. [/quote]

https://www.audioholics.com/amplifier-reviews/ftc-amplifier-rule-help-protect-home-audio-consumers-today

 

If the industry won’t establish and enforce standards then we are reduced to getting government involved which is rarely the best solution.

My quick summary:

Regarding 16 vs 24bit/sample resolution: As a streaming/transport format there will be no audible gain as long as studios are finally compressing the dynamic range of their master recording to fit into the 96dB provided by a 16bit representation of a signal. Also, as has been said before, I doubt anyone (even with golden ears) can hear the difference as 96dB SNR sounds "fantastic" while 144dB (which is what you theoretically get from 24bit) is just overkill. However, as an internal format in studio- as well as in listetning equipment 24bit/sample resolution makes total sense for doing proper volume control and eq in the digital domain. But this is happening anyways even if your transport format is "just" 16bit/sample.

Regarding sampling rate, the discussion is a litte different though:

There seems to be common consensus that a sampling frequency of 44.1kHz is sufficient to accurately reproduce the audible frequency spectrum. In fact, according to the Nyquist Theorem this allows for reproducing frequencies up to 22.05kHz and only young children can hear frequencies above 20kHz while the hearing of an average adult Joe is capped at 18 or even just 16kHz. So, all good here? Well not quite...

Ever since the CD appeared in the 80's many audiophiles keep claiming that a good analog record still offers more accurate reproduction of the sound stage and more precise positioning and depth of the instruments. They are right!

This is because there is a (incorrect) notion that equates the frequency spectrum with only the amplitude spectrum but it neglects the corresponding phase spectrum. While it's true that the human ear (and brain) cannot hear the amplitude of frequencies above, say, 18kHz our two ears can extremely well detect phase differences between frequencies that are much higher! So while we cannot hear those frequencies as tones, we can detect the tiny differences in runtime which it takes those inaudible frequencies to arrive at the left and right ear respectively. In other words, our spatial location capabilities are of much higher resolution than our frequency hearing capabilities. Btw, this effect is heavily used by 3D sound systems like Dolby Atmos or THX.

This is why digital audio with increased sampling rates of 96kHz or even 192kHz would indeed provide a very noticeable benefit as it allows for more precise positioning and depth of the sound sources.

I say "would" because every track from Amazon labeled "Ultra HD" which I have seen (or been listeing to) so far is just 24bit/44.1kHz. So it gives me the "useless" 24bit/sample resolution but falls short of providing higher sampling rates which could really make an audible difference.

 

As long as you get HD it’s “fantastic”, there is currently no audible difference to “Ultra HD”. My hope is they provide more and more content higher sampling frequencies in the future. Then it will make a difference!
    

 

My quick summary:

Regarding 16 vs 24bit/sample resolution: As a streaming/transport format there will be no audible gain as long as studios are finally compressing the dynamic range of their master recording to fit into the 96dB provided by a 16bit representation of a signal. Also, as has been said before, I doubt anyone (even with golden ears) can hear the difference as 96dB SNR sounds "fantastic" while 144dB (which is what you theoretically get from 24bit) is just overkill. However, as an internal format in studio- as well as in listetning equipment 24bit/sample resolution makes total sense for doing proper volume control and eq in the digital domain. But this is happening anyways even if your transport format is "just" 16bit/sample.

Regarding sampling rate, the discussion is a litte different though:

There seems to be common consensus that a sampling frequency of 44.1kHz is sufficient to accurately reproduce the audible frequency spectrum. In fact, according to the Nyquist Theorem this allows for reproducing frequencies up to 22.05kHz and only young children can hear frequencies above 20kHz while the hearing of an average adult Joe is capped at 18 or even just 16kHz. So, all good here? Well not quite...

Ever since the CD appeared in the 80's many audiophiles keep claiming that a good analog record still offers more accurate reproduction of the sound stage and more precise positioning and depth of the instruments. They are right!

This is because there is a (incorrect) notion that equates the frequency spectrum with only the amplitude spectrum but it neglects the corresponding phase spectrum. While it's true that the human ear (and brain) cannot hear the amplitude of frequencies above, say, 18kHz our two ears can extremely well detect phase differences between frequencies that are much higher! So while we cannot hear those frequencies as tones, we can detect the tiny differences in runtime which it takes those inaudible frequencies to arrive at the left and right ear respectively. In other words, our spatial location capabilities are of much higher resolution than our frequency hearing capabilities. Btw, this effect is heavily used by 3D sound systems like Dolby Atmos or THX.

This is why digital audio with increased sampling rates of 96kHz or even 192kHz would indeed provide a very noticeable benefit as it allows for more precise positioning and depth of the sound sources.

I say "would" because every track from Amazon labeled "Ultra HD" which I have seen (or been listeing to) so far is just 24bit/44.1kHz. So it gives me the "useless" 24bit/sample resolution but falls short of providing higher sampling rates which could really make an audible difference.

 

As long as you get HD it’s “fantastic”, there is currently no audible difference to “Ultra HD”. My hope is they provide more and more content higher sampling frequencies in the future. Then it will make a difference!
    

 

 

Cite?

This is why digital audio with increased sampling rates of 96kHz or even 192kHz would indeed provide a very noticeable benefit as it allows for more precise positioning and depth of the sound sources.

On that basis the difference between Red Book and Hi Res in any blind test should be like ‘night and day’, and yet: https://www.realhd-audio.com/?p=6993

The author nails it in this paragraph: “Is I’ve often stated in these articles, it is the production path that establishes the fidelity of the final master. Things like how a track was recorded, what processing was applied during recording and mixing, and how the tracks were ultimately mastered. If all of these things are done with maximizing fidelity as the primary goal, a great track will result.”

Again, 16bit/44.1kHz is completely sufficient in terms of fidelity, as it keeps the quantization noise low enough (-96dB) and reproduces all the audible frequencies (up 22.05kHz).

I should have said, that most current music productions do not take full advantage of the higher spatial resolution you get when using 96kHz sampling frequency and it’s debatable whether a rock/pop production would ever exploit it. With classic music, when done properly, you can definetly hear it.

Anecdotically, I remember when hearing a keynote from one of the invertors of THX at an IEEE signal processing conference back in 2000. He really made the point why 192kHz sampling frequency is required if you want to accuately reproduce the gun fire of a laser blaster flying across a cinema theatre.   

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So what audio quality do you get with a home theatre room setup where the rear speakers are not hi res compatible? For example, a Beam with Play:1s for surround.  Does it matter if you are in full mode or not?

 

I am curious about this. 

My quick summary:

Regarding 16 vs 24bit/sample resolution: As a streaming/transport format there will be no audible gain as long as studios are finally compressing the dynamic range of their master recording to fit into the 96dB provided by a 16bit representation of a signal. Also, as has been said before, I doubt anyone (even with golden ears) can hear the difference as 96dB SNR sounds "fantastic" while 144dB (which is what you theoretically get from 24bit) is just overkill. However, as an internal format in studio- as well as in listetning equipment 24bit/sample resolution makes total sense for doing proper volume control and eq in the digital domain. But this is happening anyways even if your transport format is "just" 16bit/sample.

Regarding sampling rate, the discussion is a litte different though:

There seems to be common consensus that a sampling frequency of 44.1kHz is sufficient to accurately reproduce the audible frequency spectrum. In fact, according to the Nyquist Theorem this allows for reproducing frequencies up to 22.05kHz and only young children can hear frequencies above 20kHz while the hearing of an average adult Joe is capped at 18 or even just 16kHz. So, all good here? Well not quite...

Ever since the CD appeared in the 80's many audiophiles keep claiming that a good analog record still offers more accurate reproduction of the sound stage and more precise positioning and depth of the instruments. They are right!

This is because there is a (incorrect) notion that equates the frequency spectrum with only the amplitude spectrum but it neglects the corresponding phase spectrum. While it's true that the human ear (and brain) cannot hear the amplitude of frequencies above, say, 18kHz our two ears can extremely well detect phase differences between frequencies that are much higher! So while we cannot hear those frequencies as tones, we can detect the tiny differences in runtime which it takes those inaudible frequencies to arrive at the left and right ear respectively. In other words, our spatial location capabilities are of much higher resolution than our frequency hearing capabilities. Btw, this effect is heavily used by 3D sound systems like Dolby Atmos or THX.

This is why digital audio with increased sampling rates of 96kHz or even 192kHz would indeed provide a very noticeable benefit as it allows for more precise positioning and depth of the sound sources.

I say "would" because every track from Amazon labeled "Ultra HD" which I have seen (or been listeing to) so far is just 24bit/44.1kHz. So it gives me the "useless" 24bit/sample resolution but falls short of providing higher sampling rates which could really make an audible difference.

 

As long as you get HD it’s “fantastic”, there is currently no audible difference to “Ultra HD”. My hope is they provide more and more content higher sampling frequencies in the future. Then it will make a difference!
    

 

 

Cite?

Cite what??