Understanding the Role of DACs in a Simple Audio Setup

[WoodyLuvr]

I'll check out sound on sound. I can only fit so much information in my brain for any given hobby but hopefully I can be more objective with my purchases in the future, as well as information I parrot to others. I've already learned quite a bit just from this conversation. Thanks again!
Sorry for not writing a longer message I'm a bit tied up right now.

@BrokeAudiophileMan - a very good day to you.

Firstly, hats off to you for both your humbleness in apologizing and for wanting to learn; considering different experiences and perspectives isn't always easy to do. With that said, don't hesitate to just "do you". Have fun and enjoy the experience the way you want to. For example, some people enjoy the gear and the collecting side of the hobby as much as they do listening to the music which is perfectly fine, to each their own. There is no wrong or right way .

Secondly, coming back to your original post... the following video is a completely different perspective to consider. It is a most excellent introductory lesson to ADC & DAC. The video also offers some interesting opinions and caveats about the hobby. Do I agree with everything that is said? No, of course not but it is presented in such a compelling and well put manner that it is hard to not warrant some careful consideration and reflection.



Thirdly, the greatest bane of forums is that tone and intent both seem to go right out the door and the coldness of text prevails. WIth misunderstanding, arrogance, thoughtlessness, over-sensitivity, and even keyboard rage replacing all normal (natural) modes of communication as if in person. Thus forum discourse is not truly reflective of how we would behave and engage with one another in person, face-to-face... I must always remind myself of this when on fourms.

Cheers!

 

[gregorio]

the following video is a completely different perspective to consider. It is a most excellent introductory lesson to ADC & DAC. The video also offers some interesting opinions and caveats about the hobby. Do I agree with everything that is said? No, of course not but it is presented in such a compelling and well put manner that it is hard to not warrant some careful consideration and reflection.

I’m glad you don’t agree with everything that is said but wow, it’s just packed with falsehoods and BS. It’s the opposite to “a most excellent introductory lesson”! It’s certainly a “completely different perspective” in a similar way that flat earthers have a completely different perspective but is it one that should be considered?

Unfortunately, many audiophiles fall for this approach; “it is presented in such a compelling and well put manner”. They don’t really understand the facts or underlying principles and fact checking all the assertions would be hugely laborious and impractical, so if they want to know something they have little choice but to accept the veracity of what they’re being told on the basis that the presenter is nice, seems believable, is compelling and has a well put manner. Unfortunately, that’s a terrible basis for determining veracity! People with all those qualities can be just as misinformed or misguided as anyone else and having all those qualities is actually a requisite for all good scammers/conmen!

When we’re dealing with facts, especially proven ones, there is not “a completely different perspective to consider”, there’s the perspective that aligns with those facts or a different perspective that is wrong!

I won’t go through everything he got wrong because that would take ages and to be honest I gave up when his defining test for a great DAC was how well it inspired him to draw a star constellation! But he starts off with the infinite number of points on a curve fallacy. 100% of the information (within a specified bandwidth) can be captured and reproduced with a finite number of points, a fact that was mathematically proven in 1948 by Claude Shannon, upon which the entire digital age is based and if it were wrong, then the digital age would not exist. This fact alone invalidates most of his subsequent assertions, although as with any good misinformation, there are quite a few valid assertions along with the invalid ones and BS conclusions.

I would not advise this video as a source of learning (except if you want to learn how to misrepresent something!), you’ll walk away with as much if not more misinformation than you started with!

G

 

[WoodyLuvr]

I’m glad you don’t agree with everything that is said but wow, it’s just packed with falsehoods and BS. It’s the opposite to “a most excellent introductory lesson”! It’s certainly a “completely different perspective” in a similar way that flat earthers have a completely different perspective but is it one that should be considered?

Unfortunately, many audiophiles fall for this approach; “it is presented in such a compelling and well put manner”. They don’t really understand the facts or underlying principles and fact checking all the assertions would be hugely laborious and impractical, so if they want to know something they have little choice but to accept the veracity of what they’re being told on the basis that the presenter is nice, seems believable, is compelling and has a well put manner. Unfortunately, that’s a terrible basis for determining veracity! People with all those qualities can be just as misinformed or misguided as anyone else and having all those qualities is actually a requisite for all good scammers/conmen!

When we’re dealing with facts, especially proven ones, there is not “a completely different perspective to consider”, there’s the perspective that aligns with those facts or a different perspective that is wrong!

I won’t go through everything he got wrong because that would take ages and to be honest I gave up when his defining test for a great DAC was how well it inspired him to draw a star constellation! But he starts off with the infinite number of points on a curve fallacy. 100% of the information (within a specified bandwidth) can be captured and reproduced with a finite number of points, a fact that was mathematically proven in 1948 by Claude Shannon, upon which the entire digital age is based and if it were wrong, then the digital age would not exist. This fact alone invalidates most of his subsequent assertions, although as with any good misinformation, there are quite a few valid assertions along with the invalid ones and BS conclusions.

I would not advise this video as a source of learning (except if you want to learn how to misrepresent something!), you’ll walk away with as much if not more misinformation than you started with!

G

Wait a minute... the world isn't flat?!

Have you ever considered creating your own introductory video covering a few of the basics to help us all out especially where you think audiophiles are going wrong?

 

[gregorio]

Have you ever considered creating your own introductory video covering a few of the basics to help us all out especially where you think audiophiles are going wrong?

Not really. I’ve been on camera publicly a few times, interviewed or appearing in connection with some project or artist I was working with but I hated doing it, hating seeing myself afterwards and just wasn’t much good at it TBH. Fortunately, in general no one much wanted to see me on TV anyway, with the possible exception of my mum and I’m not certain even she did!

I could write something down instead I suppose but I’ve never gotten round to it. I’ve written a few published articles in the past regarding audio recording/creation but not specifically about audiophile myths.

G

 

[bigshot]

There are links to two videos in my sig file about audio myths from the AES that go over some major points and provide download links to the test files so you can listen to them yourself.

 

[old tech]

I think where most get it wrong (as in that video) is thinking that the sample points are joined by a straight line, steps or no line at all. If you're thinking this way then sure, increasing sample points will increase the accuracy of what is being reproduced. The better way of thinking about it is thinking mathematically like algebra. If you were to reproduce a picture of a circle all you need are three sample points, that will have all the information to redraw the circled perfectly as long as the (let say) DAC knows it is reproducing a circle. Increasing the sample rate will not give a more accurate circle as the samples already have all the required information. It is a lot more complex with audio and video electrical signals as they have a time element but conceptually this is a better way of looking at it than the "stair steps" fallacy.

 

[VNandor]

Even two points is enough to define a circle, you just have to agree that one coordinate is the center and the other one is a point of the perimeter.

A circle can be drawn on a 2D plane (X and Y coordinates) just like how an electrical signal can be drawn on a 2D plane where the X-axis could represent time and the Y-axis could represent Voltage, so the curve is perfectly capable of representing a voltage changing over time, signals aren't any different or more complex than a 2D shape in that sense.

 

[Lohil]

Hi everyone,

I’ve been diving into the world of DACs and wanted to share some insights and get your thoughts. Starting with a basic setup of PC -> DAC -> AMP -> Headphones, it’s clear that we need a DAC that offers:

1. Uncolored Sound: The DAC should not add any coloration to the sound.
2. No Audible Distortion: It should have minimal to no audible distortion.
3. Linear Output Across All Frequencies: The output should be linear across the entire frequency range.
4. Balanced Output with 4Vrms: This ensures a strong and clean signal.

These specifications are measurable in lab conditions and can be clearly defined. For instance, the Topping D10 Balanced, which costs just over $100, meets these criteria excellently.

Despite this, I still see threads and messages where people claim that a DAC sounds “good” or “bad,” and discussions about DACs costing thousands of dollars that, in some cases, measure worse electronically than the Topping D10 Balanced.

So, my question is: Do audiophiles prefer a DAC that adds color to the sound, or do they seek a perfectly linear and accurate output? From a common-sense perspective, I believe a DAC should be as transparent as possible, leaving any desired coloration to the AMP.

Am I wrong in thinking this way?

I don’t consider myself an expert and could be completely mistaken. If so, I’d love to hear your opinions!

There's been quite a bit of back and forth on this thread already and I've only just skimmed it, so hopefully I'm not going over what's already been said. To the question directly from my perspective I'd agree, a DAC ideally faithfully recreates an analogue of what was once analog but is now digital for the time being. Any coloration therefore should later come from an amp or the kinetics of the equipment itself being used to create the sound.

The issue from a technical standpoint is that such a thing is never really possible / a very difficult problem.
You have of course this classic image of a digital representation of a sin wave and the noise that it generates as a result over time, Source

Now this above would be very noisy and is more just to be illustrative as ultimately these transitions would be better sampled, smoothed out by filtering and ultimately even smoothed partly by the kinetics of the the w/e you're using to reproduce the sound.

But the overall problem remains I'm trying to take a continuous waveform, discretize it, and then take that discretized waveform and make something continuous out of it again.
So in the end all we have are these points in time, but no information about the smooth curve on which they connect to one another which will always impart a change to the sound. So the DAC designer has to figureout how to approch this problem and that decision will make an effect on the final sound. As for approximations themselves how close of an approximation to a continuations waveform do you need to get before it no longer effects the sound perceptually, I don't know, but is of interest to me.
And this is just the issues a perfect DAC might have, which can produce a specific voltage at a specific point in time - there is of course a host of electrical challenges then to the degree of accuracy you can accurately reproduce the individuated samples.

So tl;dr and to get back to the og question every DAC could be said to effect the sound in some way, you can scientifically measure what it is that the DAC is doing to that sound, but imo what exactly makes "good sound" or in this context "a good approximation" is not totally understood.

 

[XTF1]

But the overall problem remains I'm trying to take a continuous waveform, discretize it, and then take that discretized waveform and make something continuous out of it again.
So in the end all we have are these points in time, but no information about the smooth curve on which they connect to one another which will always impart a change to the sound.

Simply untrue.
I think you may benefit going back to the basics of digital signal processing and review the Nyquist-Shannon theorem…

 

[Lohil]

Simply untrue.
I think you may benefit going back to the basics of digital signal processing and review the Nyquist-Shannon theorem…

well yes for a summation of sinewaves below a certain frequency, but of course reality does not magically cut off at 20Khz, if it did any sample rate above that of a CD would be pointless.

 

[XTF1]

well yes for a summation of sinewaves below a certain frequency, but of course reality does not magically cut off at 20Khz, if it did any sample rate above that of a CD would be pointless.

Yes, the hearing reality of a human fades away drastically beyond 20 kHz (and well below that for many, me included ). So it is indeed pointless…

Anyway, the theory still stands above 20 kHz: 768 kHz sampling still allows perfect reproduction of a 384 kHz signal.

Oh, and what kind of audible signal is not a summation of sine waves?

 

[castleofargh]

There's been quite a bit of back and forth on this thread already and I've only just skimmed it, so hopefully I'm not going over what's already been said. To the question directly from my perspective I'd agree, a DAC ideally faithfully recreates an analogue of what was once analog but is now digital for the time being. Any coloration therefore should later come from an amp or the kinetics of the equipment itself being used to create the sound.

The issue from a technical standpoint is that such a thing is never really possible / a very difficult problem.
You have of course this classic image of a digital representation of a sin wave and the noise that it generates as a result over time, Source

Now this above would be very noisy and is more just to be illustrative as ultimately these transitions would be better sampled, smoothed out by filtering and ultimately even smoothed partly by the kinetics of the the w/e you're using to reproduce the sound.

But the overall problem remains I'm trying to take a continuous waveform, discretize it, and then take that discretized waveform and make something continuous out of it again.
So in the end all we have are these points in time, but no information about the smooth curve on which they connect to one another which will always impart a change to the sound. So the DAC designer has to figureout how to approch this problem and that decision will make an effect on the final sound. As for approximations themselves how close of an approximation to a continuations waveform do you need to get before it no longer effects the sound perceptually, I don't know, but is of interest to me.
And this is just the issues a perfect DAC might have, which can produce a specific voltage at a specific point in time - there is of course a host of electrical challenges then to the degree of accuracy you can accurately reproduce the individuated samples.

So tl;dr and to get back to the og question every DAC could be said to effect the sound in some way, you can scientifically measure what it is that the DAC is doing to that sound, but imo what exactly makes "good sound" or in this context "a good approximation" is not totally understood.

Those graphs illustrate audio DACs like this picture illustrates cooking:

You're showing first order, 1bit, no noise shaping, no filter, leading to a crap signal and an SNR of 6dB!!!!!!!!!

 

[bigshot]

well yes for a summation of sinewaves below a certain frequency, but of course reality does not magically cut off at 20Khz, if it did any sample rate above that of a CD would be pointless.

Human hearing cuts off at 20kHz and for the purposes of listening to music in the home annything above that is pointless .

 

[Lohil]

Those graphs illustrate audio DACs like this picture illustrates cooking:

You're showing first order, 1bit, no noise shaping, no filter, leading to a crap signal and an SNR of 6dB!!!!!!!!!

Haha yes that would be an apt comparison

Yes, the hearing reality of a human fades away drastically beyond 20 kHz (and well below that for many, me included ). So it is indeed pointless…

Anyway, the theory still stands above 20 kHz: 768 kHz sampling still allows perfect reproduction of a 384 kHz signal.

Oh, and what kind of audible signal is not a summation of sine waves?

Well yes nothing stops you from picking an arbitrarily high number of samples and this then gets to the question I raised as to at what point does a change no longer perceptually effect the human hearing. There is the camp that says anything above 44.1 Khz is effectively meaningless, but there is argument as to why it could need to go higher given missing phase information or higher order frequencies aliasing down to what might be perceptible.

In any case the point of the image and my statement on not having any information is to illustrate how (given an implied non infinite sample rate) given two sample points you will be making an approximation of the original waveform which will always lead to an inherent non neutrality of the DAC.

 

[bigshot]

People argue about a lot of silly things… but inaudible still doesn’t matter in home audio. 16/44.1 is all you need to listen to music with human ears.