Is Digital Audio Transmission Analog? [video]

[DonR]

While he does come across that way on the podcast, that is not his real position. To wit, I followed up with him on that very thing and offered to come on his show and explain these things. He turned me down.

That would be akin to Martin Luther lecturing the Pope. I couldn't see the Pope taking up that offer either.

 

[amirm]

That would be akin to Martin Luther lecturing the Pope. I couldn't see the Pope taking up that offer either.

I am with you but if you listen to the podcast, he makes it sound like he is a layman hungry for technical explanation. This is/was quite contrary to the content of his videos. I took him on his word when I made my offer, only to realize that the demonstrated openness in his podcast doesn't really exist.

 

[DonR]

I am with you but if you listen to the podcast, he makes it sound like he is a layman hungry for technical explanation. This is/was quite contrary to the content of his videos. I took him on his word when I made my offer, only to realize that the demonstrated openness in his podcast doesn't really exist.

Ahh... two-faced.

 

[MRC01]

I disagree that "digital is about discrete steps". There are no advantages to discrete steps, it's just an unavoidable, practical consequence of being about numbers. A good hint of that is that we strive to reduce the step size as much as practical (24-bit audio, 32- and 64-bit float processing). Sampling is about discrete time, digital is about storing them as numbers. Discrete steps are about neither, just about resolution.

It's discrete in both dimensions. The samples values are encoded as discrete rather than continuous. And the time intervals over which the samples are taken are also discrete.

"...they don't have to be numbers, and numbers are incidental."—Oh? As a DSP guy, I find that pretty statement pretty hard to defend—care to try? I don't care if you want to call them symbols or whatever, in the end you've only made up a new numbering system. How are you going to do a gain change if they aren't numbers? Filter? FFT? You'll need to do math, with numbers.

Generally speaking, digital is about discrete encoding, and discrete encodings may or may not use numbers, though in the case of audio it is with numbers. My point is that it's not the numbers that make it discrete.

 

[Axo1989]

Ahh... two-faced.

Or, one side of a story.

 

[earlevel]

It's discrete in both dimensions. The samples values are encoded as discrete rather than continuous. And the time intervals over which the samples are taken are also discrete.

Did you miss my point? Being discrete in level is simply a necessity of digital, so we can't have infinite bits. I don't know what your point is in belaboring the fact that the values are quantized. In digital, the finer the quantization (up to the point where it doesn't matter because it's close enough), the better. It's you who only mentioned discrete in levels, I mentioned both.

Generally speaking, digital is about discrete encoding, and discrete encodings may or may not use numbers, though in the case of audio it is with numbers. My point is that it's not the numbers that make it discrete.

Woah, you clearly have not understood what I wrote. Show me where I said it's "the numbers that make it discrete". I went out of my way to separate the terms. And sampling is always analog sampling (because we're sampling an analog signal); if we want it to be digital, we then convert a briefly-held sample converted to a number and store or transmit it. Please go back and read both posts, I made this very clear.

"and discrete encodings may or may not use numbers"—of course, we can store it as a voltage in a BBD or CCD—I said this.

If you mean that they don't have to be numbers of some sort, that's silly. OK, assign unicode characters (or bimaps, or whatever you want) to levels as you see fit. Now, either build a computing device that operates on those unicode characters (bitmap, whatever) in a mathematically correct way (an insane path to take), and a DAC that accepts them as well, or convert them to numbers that you can execute in an existing cpu. Or, just store them as proper numbers. Look, I even mentioned other number systems, just for someone like you—go back and read.

But to say they aren't numbers, or don't have to be numbers, no. Whether they are numbers or proxies for numbers, the bottom line is that they need to be numbers for any signal processing, and they need to be numbers to be fed to any audio DAC in order to listen to what was sampled. What is the point in pretending they could be anything?

"though in the case of audio it is with numbers"—what exactly did you think we were talking about in this thread? My posts specifically cited audio. Digital means that it pertains to digits—it's in the name.

Are you worried that I don't understand the process, or that I'm not describing it the way you would, and are taking me to task for it?

 

[Ler0ck]

I’m waiting this day soooo long. Great video

 

[oscar_dziki]

A new argument has developed that transmission of digital audio is really analog. And for this reason, everything digital can be subject to audible difference from digital audio cables to digital output of streamers. This was emphasizes in a video by Darko Audio saying this explains his subjective opinion of streamers sounding different. I address this in this video and how there is some validity in what he says but his end conclusions are incorrect:

Coming up next on Darkos channel: "Audiophile Pendrives comparison - which provides the deepest bass from your FLAC files"? Stay tuned folks!

 

[Blumlein 88]

I want a test of the effects of different types of internet optical fiber in streaming music.

 

[voodooless]

I want a test of the effects of different types of internet optical fiber in streaming music.

Just imagine what coloring the side of the fiber with a green pen will do

 

[Awsmone]

Sorry if someone pointed this out already in 6 preceding pages, but of course we can measure properties of bottled water. And there is no doubt that some properties, above some threshold, could make a taste difference. Which would be verifiable in a blind difference taste test.

Darko's premise is stupid on its face.

Absolutely correct, his analog is flawed

https://www.news.com.au/lifestyle/f...e/news-story/13cb4a17b1fc81c50b21e6cf532172c1

this australia enquiry showed the tap water was probably best

I liked the analogy that selling bottled water was about selling plastic bottles as the water had virtually no commercial value

sound like audio cables sales

 

[audio_tony]

A few years back I wrote to HiFi World to complain about the review of a USB cable, where the reviewer drew parallels with analogue transmission.

I received a reply from Noel Keywood (himself an engineer) defending the review, when he clearly should have known better.

This is a paragraph from the review (and the part that irked me)

"Normally, when you push music through a USB cable, the data, which arrives in blocks, includes narrow bits which represents the high frequency portions of the final music. Within current USB cables, these bits are largely lost because the cable isn't fast enough to cope, the sampling continues but the narrow bits are largely ignored because they are seen as errors."

EDIT: Link to my letter and Noel's response. It's a little way down the page under the heading "Cable Complaint"

EDIT (2): I found a link to the original review.

 

[dartinbout]

I want a test of Darko's bank balance as it coordinates with his reviews. At least with Guttenberg's reviews, he sites interesting music for me to pursue. Darkos' electronica reminds of the cheap speaker in my 80's 286. IMHO music is what you get when humans play instruments not when they write Excel macros.

 

[Vacceo]

I want a test of Darko's bank balance as it coordinates with his reviews. At least with Guttenberg's reviews, he sites interesting music for me to pursue. Darkos' electronica reminds of the cheap speaker in my 80's 286. IMHO music is what you get when humans play instruments not when they write Excel macros.

I find both recommending music as boring, uninteresting and even worse, mystifying.

Audio gear is not about music, the system is "dumb" and does not know if what you feed it is Monteverdi, the Sex Pistols or the recorded noises of a construction site. That is why understanding how reproduction works is crucial: the what is up to you, the how is what the manufacturer gives you.

 

[Blumlein 88]

Just imagine what coloring the side of the fiber with a green pen will do

I still have one of those green pens. My internet comes over wireless link from a relative a few hundred yards away. How do I apply the pen to that?

 

[PeteL]

I disagree that "digital is about discrete steps". There are no advantages to discrete steps, it's just an unavoidable, practical consequence of being about numbers. A good hint of that is that we strive to reduce the step size as much as practical (24-bit audio, 32- and 64-bit float processing). Sampling is about discrete time, digital is about storing them as numbers. Discrete steps are about neither, just about resolution.

"...they don't have to be numbers, and numbers are incidental."—Oh? As a DSP guy, I find that pretty statement pretty hard to defend—care to try? I don't care if you want to call them symbols or whatever, in the end you've only made up a new numbering system. How are you going to do a gain change if they aren't numbers? Filter? FFT? You'll need to do math, with numbers.


This just comes down to what words you like to use, but we're talking about audio in this thread, not the sense of touch or taste. As such, I don't think it does anyone any good to call something like AES-EBU "analog". It's a digital signal in the continuous time domain—more simply, "digital". Analog may imply "a smooth continuum of signal", but a continuous signal doesn't necessarily imply an analog signal.

It won't make me mad if you want to call AES-EBU "analog", I'm just saying I don't think it helps anyone. We all know what it means when someone says "analog audio". It's something that, on an oscilloscope, looks like what we expect the speaker to do when it's playing back that audio.

I think you are mixing up the "discrete steps" of a dynamic range limited sampling process, to the "discrete states" which is simply high or low voltage of a digital transmission which is what the OP was referring to. Further more, I am not sure really what you mean with discrete steps being about "resolution", I know we hear it that way sometimes but it's a flawed reasoning. The word length ultimately only define the dynamic range, not the "resolution". 24 bits have a lower noise floor than 16, nothing else, it's not clear from your post if you really understand the sampling theorem and the attributes of a sinc function. We should not link resolution to word lengt, it's a bit more appropriate for and I understand that it's generally accepted to talk about High-Res for high sample rate digital audio but its flawed. The sampling rate limits the bandwith, the word lenght limits the dynamic range, Inside those limit the reproduced waveform have the same resolution at least theoretically there is not one that is more precisely resolved that the other. Or have "higher resolution".

 

[dartinbout]

I still have one of those green pens. My internet comes over wireless link from a relative a few hundred yards away. How do I apply the pen to that?

The pen goes in the pinna, "obvs".......

 

[voodooless]

How do I apply the pen to that?

Oh, you ignorant fool Everyone knows you’ll need to apply it to the tips of the antennas.

 

[manisandher]

What does matter , is that, if random noise contaminates the ground plane in ground-loop situation, then this noise can mess with the analog section of a dac, or further afield , in the amp that comes after.

OK, this is of great interest to me.

Could you elaborate a bit as to from where this noise might originate, and the mechanism by which it could affect the analogue section of the DAC, or the amp?

 

[Killingbeans]

I still have one of those green pens. My internet comes over wireless link from a relative a few hundred yards away. How do I apply the pen to that?

A fog machine and some green dye