Investigation Into Effects Of PC load On DAC Analogue Output

[March Audio]

4 hours ago, PeterSt said:

 

Maybe this is not fully OffTopic, as I realise that I only need to hook up my own and apply all the stuff I normally apply in order to see (hear) what happens. And, If I could describe SQ changes, would you be prepared to believe that (say initially) ?

Considerung the evidence to the contrary, unless you could demonstrate with a convincing blind test, frankly, no.

[semente]

6 hours ago, idiot_savant said:

So, we assume that the “noise”  is electrical rather than acoustic, and look for it influencing the output of a DAC on a non-tweaked system. And can’t find it.

We can't find noise at the DAC's ouput.

Ideally we would be testing the D/A chip's performance with different software, OS, computers, input interfaces, etc. but it is easier to just measure the (whole) DAC.

 

Is there a way to measure noise just before the signal goes into the D/A chip?

[March Audio]

7 minutes ago, semente said:

We can't find noise at the DAC's ouput.

Ideally we would be testing the D/A chip's performance with different software, OS, computers, input interfaces, etc. but it is easier to just measure the (whole) DAC.

 

Is there a way to measure noise just before the signal goes into the D/A chip?

You can look at the i2s lines but it's what comes out of the dac that is important.  If there are issues it will be seen in the dac output.

 

I will be trying several different PCs and laptops as sources.

[botrytis]

8 minutes ago, Summit said:

 

You can't back up your statements which are subjective and use censorship instead of showing evidence that support your claims. 

 

Sorry, March Audio is looking at things objectively. Saying you can hear differences, is not an objective observation, it is subjective since we know nothing about the situation, etc.  Measurements are needed.

[semente]

1 minute ago, March Audio said:

You can look at the i2s lines but it's what comes out of the dac that is important.  If there are issues it will be seen in the dac output.

 

I will be trying several different PCs and laptops as sources.

 

I understand what you are trying to say but it has been claimed often that noise "travelling along" with the signal stream affects the D/A conversion.

Could there be an aspect of the D/A chip performance that is not shown in a "traditional" set of DAC output measurements?

[semente]

In other words, is anything not being measured that could explain the perceived audible differences?

[March Audio]

3 minutes ago, semente said:

 

I understand what you are trying to say but it has been claimed often that noise "travelling along" with the signal stream affects the D/A conversion.

Could there be an aspect of the D/A chip performance that is not shown in a "traditional" set of DAC output measurements?

What youvare really asking here is are there things we can't measure but can hear?

 

Simple answers no.  We can measure way below thresholds of hearing.  However you need to use the correct measurement to find what you are looking for.  Correlation can be difficult. 

[pkane2001]

2 minutes ago, Summit said:

 

I have not said that! And no he is not presenting things objectively.

Let’s not make it a debate about who believes what. Do you have any objective evidence that contradicts what @March Audio measured? If yes, then share it, as it’ll be thousands times more convincing that any accusations of subjectivity.

[semente]

6 minutes ago, March Audio said:

What youvare really asking here is are there things we can't measure but can hear?

 

Simple answers no.  We can measure way below thresholds of hearing.  However you need to use the correct measurement to find what you are looking for.  Correlation can be difficult. 

 

If I remember correctly people were reporting poor sound quality from early solid state amplifiers and engineers said it wasn't possible. And were later proved wrong (Otala et al.).

Could a similar thing be happening here?

 

You provide a set of measurements that does not explain many reports of perceived audible differences.

Isn't there a chance that something else might need looking into / measuring?

 

I don't have a horse in this race, I am merely curious.

[March Audio]

15 minutes ago, botrytis said:

 

Sorry, March Audio is looking at things objectively. Saying you can hear differences, is not an objective observation, it is subjective since we know nothing about the situation, etc.  Measurements are needed.

Sorry I made an error, apologies @semente.

 

I meant to say that I am removing summits posts where they are inaccurate and just trying to provoke argument

[Summit]

1 minute ago, March Audio said:

Sorry I made an error, apologies @semente.

 

I meant to say that I am removing summits posts where they are inaccurate and just trying to provoke argument

 

If they would be "inaccurate", why not explain how instead of removing them?

 

Yes I questioning your statements and have asked you to post evidence of what you claim to be facts.  That is the very core in objective audio discussions. 

[March Audio]

1 minute ago, semente said:

 

If I remember correctly people were reporting poor sound quality from early solid state amplifiers and engineers said it wasn't possible. And were later proved wrong (Otala et al.).

Could a similar thing be happening here?

 

You provide a set of measurements that does not explain many reports of perceived audible differences.

Isn't there a chance that something else might need looking into / measuring?

 

I don't have a horse in this race, I am merely curious.

Actually you might be interested in the paper below which shows those conclusions about negative feedback were wrong.

 

https://www.google.com/url?sa=t&source=web&rct=j&url=https://linearaudio.net/sites/linearaudio.net/files/volume1bp.pdf&ved=2ahUKEwjp3IWGvZLxAhW6wjgGHbMSA4gQFjAAegQIBBAC&usg=AOvVaw3TQHX7dKj3pUiCoPCahlPA&cshid=1623514050065

 

It's a deliberately leading question you are posing which has no answer. 😉

 

Anyway, it's straying from the purpose of this thread.  This is about seeing if we can measure differences in a dac output, when a PC is unloaded and when loaded.

 

If you have some different measurements you would like tovsee performed we can try them.

 

Controlled subjective listening tests are the next step and I am planning to do that.

[PeterSt]

1 hour ago, pkane2001 said:

Seriously, Peter. Jitter is measurable in time domain. In fact, DeltaWave computes it for each individual sample in the file and the overall RMS value in the time domain.

 

Nice, very nice. I didn't know that DeltaWave could do that. Very interesting. I am going to try it out.

 

1 hour ago, March Audio said:

So Peter thinks nothing changes in the time domain and yet all this is about jitter - a time domain issue.

 

Ah, we're on that tour again. Quote me where I said that.

 

All I see is that you mentioned DeltaWave all right, but did not use it for Jitter measurement. But, I could have missed that.

 

So ... we are back at putting word's in other's mouths in order to next happily use that. Wait, abuse that.

 

1 hour ago, March Audio said:

He doesn't accept the demonstration of jitter not changing with PC load.

 

A new one. Just make things up, throw it over the fence and wait for buddies to upvote. You could try to quote me on that one again, but I'm afraid you are too dizzy.**

 

**): Now you can keep on repeating for the next two weeks that I called you a dizzy. No wait. I didn't say that.

[March Audio]

1 minute ago, Summit said:

 

If they would be "inaccurate", why not explain how instead of removing them?

 

Yes I questioning your statements and have asked you to post evidence of what you claim to be facts.  That is the very core in objective audio discussions. 

Because he is going round in circles arguing black is white. .  The tests performed are objective.  Him repeatedly saying the opposite is just disruptive noise

[Summit]

18 minutes ago, pkane2001 said:

Let’s not make it a debate about who believes what. Do you have any objective evidence that contradicts what @March Audio measured? If yes, then share it, as it’ll be thousands times more convincing that any accusations of subjectivity.

 

Its not the measurement per se, its the claims about PC, noise and so on.

[March Audio]

1 minute ago, PeterSt said:

 

Ah, we're on that tour again. Quote me where I said that.

 

All I see is that you mentioned DeltaWave all right, but did not use it for Jitter measurement. But, I could have missed that.

 

So ... we are back at putting word's in other's mouths in order to next happily use that. Wait, abuse that.

 

 

A new one. Just make things up, throw it over the fence and wait for buddies to upvote. You could try to quote me on that one again, but I'm afraid you are too dizzy.**

 

**): Now you can keep on repeating for the next two weeks that I called you a dizzy. No wait. I didn't say that.

"Yes, seriously. I was suggesting that nothing in the time domain changes"

[PeterSt]

1 hour ago, March Audio said:

And yet we are supposed to believe his "I hear it therefore it is" claims.

 

Ahem, and where did *I* say that ?

Maybe I did. Some times I get dizzy too. A quote again would help. Preferably from this thread because then it is in-context.

[March Audio]

Also

 

"Nobody is changing the time domain. So IMO this can only about jitter "

[PeterSt]

1 hour ago, March Audio said:

I'm sorry Peter but you have just demonstrated how little you understand about the subject.

 

Jitter dies not get averaged away in FFTs

 

Mind boggling.

Can you try Dutch please ?

[March Audio]

1 minute ago, PeterSt said:

 

Ahem, and where did *I* say that ?

Maybe I did. Some times I get dizzy too. A quote again would help. Preferably from this thread because then it is in-context.

So are you now saying that pc load variations are not audible, or that SSDs don't sound crap after all?

[March Audio]

4 minutes ago, PeterSt said:

 

Mind boggling.

Can you try Dutch please ?

Peter, you said the following:

 

"Nobody is changing the time domain. So IMO this can only about jitter "

 

This is a contradiction and demonstrates you don't understand the subject.

 

If you continue with posting pointless noise  I will just moderate and remove them.

 

[March Audio]

30 minutes ago, semente said:

 

You provide a set of measurements that does not explain many reports of perceived audible differences.

Isn't there a chance that something else might need looking into / measuring?

 

I don't have a horse in this race, I am merely curious.

Let's be clear, I am not saying that circumstances can't exist where dac outputs are affected negatively by the upstream PC.  I have already mentioned ground loops and lack of isolation.  I am planning to go on and demonstrate some of those problems.

 

However let's also be clear that unless those reports you are referring to were obtained in controlled conditions, they simply can't be trusted.  

[PeterSt]

1 minute ago, March Audio said:

Let's be clear, I am not saying that circumstances can't exist where dac outputs are affected negatively by the upstream PC.  I have already mentioned ground loops and lack of isolation.

 

Balanced interlinks.

[PeterSt]

2 minutes ago, March Audio said:

I am planning to go on and demonstrate some of those problems.

 

Wait ... that is a good one. So yes please, demonstrate for example the output of two bit perfect players and how they change the output of the DAC you measure relatively to each other.

That should be doable.

[PeterSt]

PS: Preferably so that we can do this at home. Me ahead.