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Topic: What is a "high resolution audio system"? (Read 1571 times) previous topic - next topic
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What is a "high resolution audio system"?

I read the expression "high resolution audio system" all the time, and I don't understand what that means. I understand resolution in video, in film, in digital audio. But how can analog audio have a resolution? What can a better amplifier or speaker "resolve"? Noise, distortion, phase, it's all clear to me. But how any of those can impact "resolution"?

Of course, I suspect it is a made up audiophile expression. But I keep reading it even from people that I deem unsuspectable. So, is there a meaning that eludes me?

(mind you, I'm not a troll. I've been reading HA for many, many years, and I consider it the ONLY bs-free place on the internet when it comes to audio)

Re: What is a "high resolution audio system"?

Reply #1
As marketing slogans I am not confident there is any distinction between "fidelity", "definition" and "resolution" except the order of appearance?
While the "high fidelity" phrase has been around since the bronze age, "high definition" might have been introduced with HDCD and about at the same time you got marketing spin terms like "super bit mapping" and "extended resolution" - at 16 bit resolution yes, as far as I understand it was only how about resampling and dithering.
Actually, part of the extra "resolution" HDCD boasted was from the dithering process - the mid nineties was obviously a time where nobody was doing dithering so the ones who did (= everyone!) could boast extra resolution. Or was it definition.

There must have been more catchphrases with similar (lack of precise) content? ("Definition" seems to have died out with HD DVD?)

Re: What is a "high resolution audio system"?

Reply #2
With absolutely no authority, I would say "high resolution" in digital audio system was anything over 16 bits and over 44.1 kHz sample rate per channel.

If the signal path is purely analogue, then high resolution would have to mean very low noise and wide bandwidth end-to-end.

Whether the phrase is actually applied in that way is a question of marketing.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: What is a "high resolution audio system"?

Reply #3
From a wide perspective, "high resolution audio" can have many meanings, but for products bearing this logo:

The meaning is defined by JAS, and the use of this logo is not free:
https://www.jas-audio.or.jp/english/hi-res-logo-en
https://www.jas-audio.or.jp/english/hi-res-logo-en/hi-res-logo-application-process
Which means people buying products with this logo is paying to JAS.

Re: What is a "high resolution audio system"?

Reply #4
From the above links:
Quote
"Hi-Res Audio" logo applicable products JAS defines is to fulfill the following specification on the recording, reproduction and signal transition process

<Analogue process>
(1) Microphone response performance: 40 kHz or above during recording
(2) Amplification performance: 40 kHz or above
(3) Speaker and headphone performance: 40 kHz or above

<Digital process>
(1) Recording format: Capability of recording using the 96kHz/24bit format or above
(2) I/O (Interface): Input/output interface with the performance of 96kHz/24bit or above
(3) Decoding: File playability of 96kHz/24bit or above (FLAC and WAV both required)
(In case of self-recording equipment, FLAC or WAV file is required as minimum condition)
(4) Digital Signal Processing: DSP processing of 96kHz/24bit or above
(5) D/A conversion: Digital to analog conversion processing of 96 kHz/24 bits or above

No mention of noise performance.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: What is a "high resolution audio system"?

Reply #5
Oh. So, an extra tweeter for the over-the-top octave, and the gear should be "Capable of" recording to a 96/24 format or above - but no requirement that such a resolution was actually employed?

The RIAA had another take around the same time. 403 at riaa.org now, so this is from a vendor who actually uses the logo:

From the press release, they "quote" a definition that they don't link to:
“lossless audio capable of reproducing the full spectrum of sound from recordings which have been mastered from better than CD quality (48kHz/20-bit or higher) music sources which represent what the artists, producers and engineers originally intended.”

Note, "mastered from". Read: must have been digitized to at least 48k/20 in the second to final step, because that represents the intention of artists we didn't ask. Should have called the format "Resolution Intended by Artist (Authenicated)" and lit up a LED.

Re: What is a "high resolution audio system"?

Reply #6
Thank you for your replies, all interesting.

The fact that there is no single, simple answer, means that it's not something widely known to anyone but me.

I have no trouble with the concept of high resolution DIGITAL audio. If the sampling frequency is the horizontal resolution, and the word length is the horizontal one, than you can have high and low resolution.

What prompted my question was this video: Conference by Gary Galo. The speaker is an AES member, a widely published and (apparently) respected veteran of audio. The conference, by the way, is (to me) very interesting and well presented. During the Q&A, however, he gets asked this question: "When you have a jitter problem what do you hear?", and he replies: "What I hear is that high frequencies become a little harsh, ambience gets a little drier, and sometimes the soundstage localization is not as precise. When clock jitter is high, what I hear is a throwback to the things we didn't like in early digital audio. But, again, you have to have a HIGH RESOLUTION SYSTEM to hear it. Some systems are not resolving enough to reveal those differences, but that's what I hear."

I've read this kind of reply countless times. The "system" appears to have, in those words, a "resolution" or "resolving power". Hence my question: how does one measures or quantify this "resolution"? And how can an analog system be smart enough to hide anything?

Re: What is a "high resolution audio system"?

Reply #7
Being an AES member doesn't stop people from selling snake oil. MQA's Bob Stuart is an AES member...

Audio "resolution", like other words, can mean different things depending on the context. I think 9 out of 10 times the context is marketing aimed at a less informed audience, with flawed analogies to picture/video formats.
My (charitable) interpretation of high resolution in the context of "lets you hear details" is something with low noise and distortion. So that you can crank up the volume and hear the quiet parts clearly, for example.

So I think resolution makes some sense when talking about noise or bit depth, but less sense when talking about sample rates/frequencies. James "jj" Johnston talked about bandwidth in his presentation and I think that's a standard term in other fields when talking about frequency ranges.

 

Re: What is a "high resolution audio system"?

Reply #8
I have no trouble with the concept of high resolution DIGITAL audio. If the sampling frequency is the horizontal resolution, and the word length is the horizontal one, than you can have high and low resolution.
Digital sampling frequency and word length have no effect on "resolution" in the way we commonly think of that term.  Sampling frequency simply determines the highest frequency that can be captured, and word length the maximum level.  Resolution, as in video the number of pixels/inch, has no equivalent in audio; more samples do not mean greater accuracy.

A "high resolution system" in audio is one that can reproduce the spectrum of sound that humans can hear, commonly defined as 20Hz to 20kHz, at a comfortable listening level without audible distortion.  It need not be any more complicated than that.

Phrases like "your system is not resolving enough", "you aren't trained on how to listen", and "your ears aren't good enough" are often used to shill for product or to attempt to establish a pecking order in the audiophile community.

Re: What is a "high resolution audio system"?

Reply #9
The "system" appears to have, in those words, a "resolution" or "resolving power". Hence my question: how does one measures or quantify this "resolution"? And how can an analog system be smart enough to hide anything?
I think you're being too dismissive.  An analogue system clearly can't be "smart", but it certainly can hide stuff!  Ignoring the transducers for a moment, there is an electrical signal path from input to output which is ideally linear, but actually never is.

By "linear" we mean that the graph of output voltage plotted agains input voltage is a straight line.

In practice, the transfer function depends on the input frequency, so for an input containing a broad spectrum of frequencies the output is the sum of all the input frequencies multiplied by their respective transfer functions.  For any particular frequency, the transfer function may also include a phase shift.

Then there is the problem of the transducers: taking acoustic pressure waves and converting those to an electrical signal, using the amplified electrical signal to waggle a needle (or whatever) cutting a groove in a master disc, then at the reproduction end picking up the motions of the stylus and converting those to electrical, and finally the amplified signal into a loudspeaker to recreate the acoustic signal.

The fundamental purpose of the electrical stages is to boost the power so that the input transducer can drive the output transducer with sufficient force, but is generally "shaped" to compensate for performance shortfalls in the transducer.  This shaping may not be perfectly matched to each individual transducer, so this introduces response errors.  Also, in addition to the actual wanted signal, there is an unavoidable random noise signal (hiss) injected into the signal path by the components in that signal path.

Consequently, even if it were possible to design an amplifier to have a perfectly flat and phase zero response over the entire audio spectrum (it isn't), the transducers would still impose variations in the frequency and phase response.  Any lack of linearity WILL HAVE an effect on the output, and COULD HAVE an audible effect on resolving the detail of the sound (for those with genuine ability to hear it - which does not include me).  If the fine detail of the signal is of a similar level as the hiss, it will definitely be hidden even if the system were capable of reproducing it.  (Note that transducers can also have a response which is modulated by the signal which has been present immediately before, which adds another level of complication.)

Digital avoids a lot of this, but introduces its own problems in terms of analogue to digital conversion linearity and resolution, sample clock jitter etc.  And it still has to have a microphone at the input and a loudspeaker at the output which (as noted) need shaping.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: What is a "high resolution audio system"?

Reply #10
Digital avoids a lot of this, but introduces its own problems in terms of analogue to digital conversion linearity and resolution, sample clock jitter etc.
None of those things are an audible concern given modern digital recording, mastering and distribution practices (i.e. for the past 35+ years.)
for those with genuine ability to hear it
Yup, those amazing "golden ears" I keep hearing about!

Re: What is a "high resolution audio system"?

Reply #11
I think OP wanted to express an opinion that "resolution" should be used to describe discrete and quantized properties like sample rate and bit-depth. Yet someone thinks that even digital formats don't have "resolution" as well:
https://www.youtube.com/watch?v=Rc_-eavKptY

Conversely, it is also possible that people cannot differentiate 16/44 vs lower "resolution" formats when listening through the speaker of a Fisher-Price toy. In this case one may describe the speaker on the toy does not have enough "resolution" for 16/44 audio. It is just a system's usable frequency bandwidth and dynamic range, or signal to noise ratio.

Speaking of logos and marketing, I don't own anything MQA or anything with that Hi-Res Audio logo. My PC motherboard has "Intel High Definition Audio" though. :))

Re: What is a "high resolution audio system"?

Reply #12
Sampling frequency simply determines the highest frequency that can be captured, and word length the maximum level. 
Isn't that rather the minimum, non-zero level?

Re: What is a "high resolution audio system"?

Reply #13
Speaking of logos and marketing, I don't own anything MQA or anything with that Hi-Res Audio logo. My PC motherboard has "Intel High Definition Audio" though. :))
The onboard HD intel audio of my laptop is so good that I can hear the AC charger through the 3.5mm jack. In HD.

Re: What is a "high resolution audio system"?

Reply #14
The onboard HD intel audio of my laptop is so good that I can hear the AC charger through the 3.5mm jack. In HD.

Throw that crap in the trash.  Ick!

Re: What is a "high resolution audio system"?

Reply #15
Eh, it's a quad core ivy bridge laptop so it can last another decade if it had to. A USB DAC might be in the cards if I hang around here long enough.


Re: What is a "high resolution audio system"?

Reply #17
That makes sense, I can get that to happen sometimes but it's not consistent. Scroll-wheel/mouse-movement is UI and the OS prioritises UI to feel snappy. My best guess is that the prioritisation ramps CPU frequency up and down quickly, this draws more power briefly which increases PSU interference and that's what can be heard. Subjectively it seems worse on laptops which have larger swings and more interference as everything's crammed in.

Re: What is a "high resolution audio system"?

Reply #18
Quote
he gets asked this question: "When you have a jitter problem what do you hear?", and he replies: "What I hear is that high frequencies become a little harsh, ambience gets a little drier, and sometimes the soundstage localization is not as precise. When clock jitter is high, what I hear is a throwback to the things we didn't like in early digital audio. But, again, you have to have a HIGH RESOLUTION SYSTEM to hear it. Some systems are not resolving enough to reveal those differences, but that's what I hear."
I've never heard jitter.

I don't have a link handy but some people have done experiments introducing & increasing jitter.    The conclusion is that it's not audible unless something is badly broken.   When it's intentionally made bad-enough to become audible it's heard as noise.