[gregorio]

Typically ADCs measure voltage, not current.

ADCs (and the digital process) measure/quantify the amplitude of voltage variations within an electrical current. That's it, there is nothing more, nada, zilch ... this is the basic tenet of digital audio theory, always has been, always will be until/if digital audio is replaced by some other technology. That's frankly unlikely in the foreseeable future, as the digital audio model/theory provides for the perfect recording and reproduction of audio and there's nothing better than "perfect".

G

 

[gregorio]

Um, if I do a little math, that's a huge amount of data in a matter of seconds.

No, it's a tiny amount, about 1.4 million bits (176kB) per second for two channels of it (stereo). Roughly about 0.5% of what USB2 was capable of, and less than 0.01% of what modern storage or current USB specs are capable of. It wasn't even taxing for 20 year old computers, let alone today's technology.

G

 

[Phronesis]

No, it's a tiny amount, about 1.4 million bits (176kB) per second for two channels of it (stereo). Roughly about 0.5% of what USB2 was capable of, and less than 0.01% of what modern storage or current USB specs are capable of. It wasn't even taxing for 20 year old computers, let alone today's technology.

G

But that’s my point. A string of millions of 1s and 0s is useless from a practical standpoint as a measurement. If you look at that raw data, you won’t be able to make any useful inference from it.

 

[gregorio]

A string of millions of 1s and 0s is useless from a practical standpoint as a measurement.

A string of millions of 1s and 0s is useless for ANYTHING from a practical standpoint, it's what those 1s and 0s represent that's useful, which in this case is the measurement of voltage amplitudes. Do we really need to go back to the basics of what digital data is and how binary information works?

G

 

[SoundAndMotion]

One other thing I'll mention... When I see someone take my posts and reply to them line by line or phrase by phrase, I just read a sentence or two, then skip on by to the next person's post. It takes me way too long to parse out what they are talking about if they tear the context up into tiny little scraps and argue each little detail. My time is limited and I prefer to read clear paragraphs where someone states their case in the first sentence, supports it with with evidence in the next few sentences, then sums up with a conclusion at the end. Complete thoughts that are well organized get ideas across more effectively than scraps of contextless arguments piled up in a heap. I always try to reply that way myself.

There are other posters who don't mind line by line replies. You can feel free to communicate that way with them, but I don't have the patience for that particular argumentative technique. I apologize for not reading the last section of your post. If you want to reorganize it into a clearer format, I'd be happy to read it.

Sorry, but I don't buy the above part of your post for exactly 3 reasons:

First, you do interact with people who answer you in line-by-line replies, as you did with @gregorio a little while back in the Immersive Sound thread. But gregorio's your buddy and I'm not. I get it. But honesty is better.

Second, we are all busy with our lives, but you do spend a lot of time here. It's quite a feat to have 18,792 posts right now, but I can't see how frequently you post (i.e. posts/day), because you have mentioned you were banned for a bit before Sound Science was created. So just looking at this year, 2018, it seems you have 2389 posts right now. Is that possible? I must have that wrong. Someone should check. Since this is the 324th day, so that is over 7* posts each and every day. Impressive. But are you too busy to read what I wrote.... or afraid?

Finally, you give me writing advice. Thanks! And you say that you try to abide by that yourself. But reading the word salad above what I quoted here, I see it has nothing whatsoever to do with my post. You just spat all that stuff out.

I don't have a problem with you not wanting to answer my previous reply to you. But I can't believe the reasons you gave. I think you don't want to deal with the issues I brought up. Got it.

*Edit: I had a stupid mistake above stating 70 posts/day and corrected it. Thanks to @taffy2207 for pointing this out and apologies to @bigshot

 

[SoundAndMotion]

ADCs (and the digital process) measure/quantify the amplitude of voltage variations within an electrical current.

The bold makes no sense. ADCs measure the voltage (SAR) or voltage variations (SD). Not within an electrical current. What does that mean?

And the rest of my post on measurement and recording?

 

[SoundAndMotion]

I'm trying to think of a reason why it would be important for an audio component to be able to reproduce sound that isn't present in the recording. Maybe oversampling in DACs? But that is more of a processing thing than something that is measured as opposed to recorded. Do you have any examples of that? Perhaps I misunderstand the point you are making.

Personally, I don't see any reason for audio equipment to need to reproduce sound human ears can't hear. Audibly perfect is good enough. I suppose their can be psychological reasons why someone would feel the need to control things they can't physically perceive, but I'm reasonably well balanced and practical. It isn't a problem for me.

Again, you don't respond to what I wrote (to gregorio). It has to do with the difference between measurement and recording, not reproducing sound that's not in the recording. You seem to have misunderstood. Maybe if you try again. Or ask a question. Happy to help if possible.

 

[gregorio]

[1] The bold makes no sense. ADCs measure the voltage (SAR) or voltage variations (SD). Not within an electrical current. What does that mean?
[2] And the rest of my post on measurement and recording?

1. It means that unless you have an alternating current you cannot have voltage variations which are analogous to sound waves.
2. No point responding, it doesn't change the fact that digital audio data is the measurement of voltage amplitudes and nothing else.

G

 

[Killcomic]

Every DAC and DAP I've ever owned has been transparent far beyond my ability to even hear it. I have no idea why someone would want to manufacture a colored DAC, but people keep swearing that they exist. I'd like to find one of these rare birds in the wild and figure out exactly what kind of coloration they have going on.

A half dB difference can be heard with tones, but it's not very likely that it's going to be heard when you play back music. And the human ear will certainly grow accustomed and correct for slight deviations like that. I'm looking for the clear differences I've been told exist.

Perhaps you need to test the headphone out instead of line out?

 

[bigshot]

Perhaps you need to test the headphone out instead of line out?

Then I'd be comparing the impedance characteristics, not the DAC itself. I've done comparisons of the headphone out on my portable gear because I normally use that... no difference between the line out amped and the headphone out. But I have cans that are designed to be used unamped. Headphones that aren't designed for that will need amping, and headphone out won't sound good with those cans unless you use an amp between the headphone out and the cans.

 

[SoundAndMotion]

1. It means that unless you have an alternating current you cannot have voltage variations which are analogous to sound waves.
2. No point responding, it doesn't change the fact that digital audio data is the measurement of voltage amplitudes and nothing else.

G

1- You can have alternating voltages without alternating currents. Have you had physics? Voltages are always between 2 places/points. Current flows through one place. Voltages produce current flow if there is a path, which is typical, but not required.
2- I don't deny digital audio data is voltage amplitudes versus time. But you certainly can do more: measurements on that data, e.g.:
Distortion
Noise
Spectrum, etc.
And measurement is not the same as recording. No comment on the TIM example I gave?

 

[bigshot]

First, you do interact with people who answer you in line-by-line replies, as you did with @gregorio a little while back in the Immersive Sound thread. But gregorio's your buddy and I'm not. I get it. Second, we are all busy with our lives, but you do spend a lot of time here. It's quite a feat to have 18,792 posts right now, but I can't see how frequently you post (i.e. posts/day), because you have mentioned you were banned for a bit before Sound Science was created. So just looking at this year, 2018, it seems you have 2389 posts right now. Is that possible? I must have that wrong. Someone should check. Since this is the 324th day, so that is over 70 posts each and every day. Impressive. But are you too busy to read what I wrote.... or afraid? Finally, you give me writing advice. Thanks! And you say that you try to abide by that yourself. But reading the word salad above what I quoted here, I see it has nothing whatsoever to do with my post. You just spat all that stuff out. I don't have a problem with you not wanting to answer my previous reply to you. But I can't believe the reasons you gave. I think you don't want to deal with the issues I brought up. Got it.

Gregorio is well aware that I don't read his posts when he does line by line quoting. Just ask him! My time belongs to me and I get to choose how I use it. Conciseness is a virtue. I'm using it right here in my reply to you.

You were asking me how I tested and I explained how and pointed out what I was testing for and why. I'm happy to discuss that subject if you want. I have very little interest in any of the subjects you raise in the quoted post above. You've veered way off the subject here into irrelevant argumentativeness. That isn't going to get you very far with me. Consider this a shot across the bow.

 

[gregorio]

2- I don't deny digital audio data is voltage amplitudes versus time. But you certainly can do more: measurements on that data ...

Agreed and I've already stated that just a few hours ago: "From that ONE measurement (quantised amplitude data) we can derive all kinds of other information that we can measure in numerous different ways. For example, we can process that ONE MEASUREMENT with a Fourier transform and derive all the frequency information but EVERYTHING we can measure (or not measure) is derived from that one single measurement of amplitude."

G

 

[Phronesis]

Agreed and I've already stated that just a few hours ago: "From that ONE measurement (quantised amplitude data) we can derive all kinds of other information that we can measure in numerous different ways. For example, we can process that ONE MEASUREMENT with a Fourier transform and derive all the frequency information but EVERYTHING we can measure (or not measure) is derived from that one single measurement of amplitude."

G

You're including a full description/listing of all the data as a type of measurement. To me, a measurement is a useful characterization of some aspect of an object which has practical value to a human qualified to interpret the measurement. No human can form a useful interpretation of a string of millions of 0s and 1s.

No need to drag this out further, you're choosing a definition of measurement which suits your purpose, but it's a very idiosyncratic definition which I've never seen anyone else use.

 

[bigshot]

If a number can't be interpreted by humans can it actually represent a measurement? If a tree falls in the forest and there's no one there to hear it, does it make a sound?

Does a recording studio measure a musical performance and output its measurements as frequencies and amplitudes plotted out over time?