Help GoldenSound / GoldenOne Get An Audio Precision Analyzer

[Confused]

7 hours ago, idiot_savant said:

@GoldenOne I applaud your efforts to provide objective measurements and try to provide more in-depth analysis. I would be happy to offer advice/insight, so I’ll start with this:

As unpopular as this may be, I’d really recommend looking to the efforts John Atkinson has provided over the years - he’s truly done exceptional work, trying to keep measurements consistent and I believe him to be a thoroughly decent man. 
 

your friendly neighbourhood idiot 

In terms of a large number of consistent measurements, it is also worth looking at the work of Paul Miller.  (Hifi News / AVTech Miller Audio Research)

 

Interestingly, he started out as a chemist. 

(and he worked out that MQA was not all it was claimed to be)

[Confused]

13 hours ago, GoldenOne said:

Yep paul miller certainly has some excellent stuff. Though I do wish the measurement suite was a little more thorough.

Which actually I suppose is a good question, what are some measurements that people wish were taken of more products?

 

One measurement that interests me is amplifier output impedance.  The reason for this interest comes from a time I listened to three amplifiers on the same day, with the same speakers.  The amps were at slightly different price points, with a variation in specs as you might expect.  One thing that I did pick up was a noticeable difference in the presentation of the bass.  One amp seemed to have better bass depth and accuracy, versus another that had maybe slightly more prominent upper bass, but lacked the depth and accuracy of the other.

 

Later, when I checked the specs, I noticed that one amp had a lower output impedance versus the other.  I have always suspected that this was a least a contributing factor to what I observed.  Later amp demo's seemed to follow a trend, that in terms of bass performance, my subjective preference went to amps with the lowest output impedance.  OK - This hardly meets the requirements for double blind testing or any kind of statistical significance, but it does seem to me that output impedance is given very little prominence in measurements, in comparison to power output, signal to noise ratios and similar.

 

I could also answer your question in an entirely different way.  It seems to me that the big issue with measurements, and the objective vs subjective debate is that there is very little correlation between what is observed and what is measured.

 

To take an example.  One controversial area at the moment is "audiophile" ethernet switches.  I have seen measurements of switches that show differences at the DAC, but these differences are so small that they could not possibly relate to anything auditable.  Yet there remains many reports of clear audible differences with switches.  Indeed, some people are buying switches costing $1k, $2k and even $5k.

 

So am I suggesting that you should measure switches to find out what is going on?  Not really.  OK, you could do this if you wanted to, and who knows, you might find something, but I don not think this is the right approach.  Step 1 should be establish that there is an audible difference, and this should be done with a properly controlled blind test.  Once a clear situation is established where X demonstrably sounds different to Y, then the job of the measurements would be to try to establish the exact mechanism causing the audible difference.  From here we would learn.

 

The problem as I see it is that we have a vast body of subjective observations claiming all sorts of things, but proper controlled blind tests are almost non-existent.  I know that there are some that state that blind tests do not work for whatever reason.  OK, fair enough, but I would happily take part in a blind test, and if we are to establish a scientific link between the measured and the observed, I cannot see any other way (sensibly) of doing this other than starting with an observable difference established via blind testing in a controlled way.

 

I did have a slightly crazy idea of persuading a dealer to run blind test events.  I do know of one dealer that likes to have lots of events.  Of course, conventional wisdom would dictate that this is not is the said dealers interests, he want to have sighted tests where potential customers easily "hear" the difference and then happily buy the expensive thing tried.  This is probably how it will forever work, although I would add the contrary view that I might listen to two products, think I hear a difference, but then convince myself it is probably just imagined, placebo or expectation bias, thus keeping hold of my money.  If however I could reliably hear a difference between X and Y in blind conditions, this would give me the confidence to spend.  A crazy thought I know, so no need for anyone to explain why it will never happen.

 

So this is the key I think, somehow we need to organise more independent blind testing.  From this, interesting things to try and measure could follow, and if measurable differences were found, we could then try to correlate this to what is already established as audibly different.

 

Without such blind testing, I am not sure if more measuring will get us anywhere?

[Confused]

On 6/14/2021 at 2:51 PM, GoldenOne said:

So I'm going to have an APx555 here for a couple weeks (not mine, not keeping it, just here temporarily). This likely won't be long enough to do some of the more in-depth stuff but I'm going to measure anything I can get my hands on just cause why not, but also will probably do a brief video explaining a little about why the APx555 is different to just using a good ADC etc.

If anyone has anything specific that they think I should do whilst it's here lmk!

I am a little surprised there was not more response to this one.  Anyway, reading through some recent threads here on AS gave me an idea of something that could be tested.

 

I believe you have an "NAA" type device?  (SOtM sMS-200?)  In other threads there has been debate about computer / PC "noise" that can find its way to the DAC, so how you play back a bit perfect file can influence the sound, depending on the configuration of the PC, software, noise etc. 

 

As a subset of such discussions, it has been suggested by some that "network attached end point" type devices should effectively be immune to whatever might be going on in the associated PC, as long as the said machine is delivering the bits, nothing else matters.  Others dispute this notion.

 

Which gives me an idea for a test.  You could measure the output of the NAA (or perhaps the output of a DAC connected to the NAA) using different PC's to feed the NAA, or maybe the same PC is different states, first just running simple playback software, then maybe have the computer mutli-task, running the playback software and at the same time with the PC running near to the processor limit running another task.  There are very many ways this could be done, but the key would be to have the feeding computer in definitively different states, or maybe use a simple LPS powered NUC versus a big noisy SMPS ridden high powered PC.

 

Just a thought, maybe it is a bad idea for some reason, maybe a more optimum test could be devised?

 

Might be interesting though?

[Confused]

2 hours ago, GoldenOne said:

Friend of mine sent a small present to keep the analyzer company. 

 

The Panther looks a little disgruntled, and maybe looks as if it is actually "leaving a small present" on your analyzer in response.

[Confused]

12 minutes ago, GoldenOne said:

I did actually touch on this briefly in my DDC video.

Using a network streamer can be a big benefit especially if you were previously using a beefy (and very electrically noisy) PC.
And dacs can and do indeed show different measurements in both things such as outright THD+N and Jitter when connected via a more ideal source such as a streamer vs a PC.
How much this change is will depend on the specific DAC, with some dacs showing very obvious changes, something like an apple dongle being a rather extreme example. And some dacs which have proper internal galvanic isolation like a Yggdrasil or May should have no change at all.

In terms of USB vs an I2S/AES/SPDIF streamer though, the latter will affect performance more due to the fact that the source device/streamer is the master clock, not the DAC itself.

Yes, I enjoyed watching your DCC video, excellent stuff.  (Although I was left wondering how a Mutec MC3+USB might have faired, but you can't test everything I guess)

 

That said, what I am proposing is slightly different.  Not a PC direct versus NAA test or similar, but a fixed NAA / DAC system, with the only variable being the PC.  The question being, does the Ethernet / NAA route reduce susceptibility to noise from a big noisy PC, or does it eliminate it completely?  Maybe you have already established this?

[Confused]

13 hours ago, Superdad said:

 

Well 2,500 EtherREGEN owners--plus thousands more using and discussing their audible experiences with other switches, clocks, filters, SFP transceivers, and cables--will disagree with you there... 

Mindful that this thread is discussing things that could potentially be measured with an Audio Precision APx555, this perhaps begs a question.

 

@GoldenOne has already mentioned that he would be happy to measure an audiophile switch or router if someone were to loan one to him.  So lets say someone provided him with an EtherREGEN, would it be possible to use a APx555 to demonstrate measurable benefits from an EtherREGEN?  If so, what measurements or measurement methodology would you propose? 

 

This is a genuine question by the way, after all, I am one of those happy 2,500 EtherREGEN users.

 

[Confused]

7 hours ago, Rexp said:

Im more interested in measured difference between recordings than hardware, for instance can you do a 16/44.1 v 24/88.2 of Daft Punks Random Access Memories? I'll send files if necessary. 

Actually, this interests me also.  As an example, I can listen to something and think that my system sounds great, clean clear, no issues.

 

Then to the nest track, and maybe I hear some very slight distortions somewhere.  Of course, this can lead to paranoid thoughts that there is something wrong with my system somewhere, something I need to fix or tweak.

 

What would interest me would be if there was someway to analyze the actual digital file to identify and quantify such distortion.  I am thinking that in practical terms this is pretty much impossible to do.  For example, how would you discriminate between distortion that is supposed to be there, say from a guitar amp of effects peddle, and something that should not be there, say caused by a microphone or electronics used during the recording.

 

Comparing alternative versions of the same recording as you mention, is much more likely to reveal something meaningful I would think.

[Confused]

I watched the unboxing video yesterday. For me it was less of an unboxing, more of a mission statement from @GoldenOne.

 

And an excellent mission statement it is too, I think I pretty much agreed with every word.

 

I think that everything that can be heard almost certainly can be measured, but I suspect that in some cases the wrong things are being measured, and the right things not at all. The key is correlating measurements with the subjective experience, something that is not happening at the moment, in some areas at least.

 

I wish @GoldenOne the very best of luck with this new venture, it will be interesting to see how this develops.