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Lead Maestro
December 7, 2021

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

  • December 7, 2021
  • 92 replies
  • 4122 views

The 13.4.1 S2 update added hi-res (Ultra HD) and Dolby Atmos audio support from Amazon Music Unlimited. With this update, Sonos released this great article about hi-res audio and how you can listen to it on Sonos. It’s a very detailed and well-written article:

https://blog.sonos.com/en-us/hi-res-audio-guide

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92 replies

Airgetlam
December 22, 2021

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. 

Bruce
December 22, 2021

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.

Stanley_4
Grand Maestro
December 22, 2021

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.

melvimbe
December 22, 2021

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. 

 

An industry, or more accurately just an industry related group, can create a standard, but they can never require compliance. All they can really do is market and educate the public on what the standard is, why it’s important, and make sure the standard is followed strictly by product that applies and claims to meet the standard.  if the public doesn’t know or care about the standard, and it’s loosely enforced, then it’s pointless.  All that takes a lot of money, and generally speaking, if it doesn’t help increase sales, why bother.   I think the different music services primary means of competing is on audio quality, so they don’t have a big interest in standards.

That said.  it seems standards pretty much existed and worked in the days of physical media.  Once everything  stated going digital and ‘customers’ pirated music in whatever format and quality they wanted, things got all shot to hell.  Even when you could start buying music digitally, the industry didn’t want you to know that the quality was worse than CD.

 

 

Danny
Lyricist III
February 7, 2022

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!
    

 

ratty
February 7, 2022

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

jgatie
February 7, 2022

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?

Lyricist III
February 7, 2022

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.   

Lyricist III
February 7, 2022

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??

jgatie
February 7, 2022

Cite what??

 

Actual evidence for your claim.