Review and Measurements of the PS Audio Stellar Gain Cell DAC

[Frank Dernie]

But I know that is the level I asked the DAC to reproduce. And it created distortion that in my setup was audible. And that setup was ordinary, with no extra amplification.

I will check the link.
I will set the gain of my system such that a 0dB signal would give a sound level of 120dB at 1m from my speakers, then listen to the signal without changing the gain.
That is the only way to tell whether it is audible or not.
I don't doubt the electrical ratio is -120dB and that is clearly measurable what I am still sceptical about is that a -120dB signal giving 0dBspl in my room will have audible distortion without amplifying it such that a 0dB signal would risk deafness, a level I would never use to listen to music...

 

[StevenEleven]

I have read from an audio engineer that while in one sense what @amirm (yes @amirm in particular) does is a bit extreme for checking what would be an audible flaw in the home, it is an industry standard practice in checking for quality in the field of audio engineering.

This thing costs $1600 and is claimed to be state of the art and the owner of the company says that if he tried to make it measure better it would sound like “dog poo” like better measuring stuff from his competitors. And in the same breath he says that the sub-par measurements of his equipment would not make any audible difference. So I would suggest he does not deserve any slack on either side of the spectrum. Did he lie the first time, or did he lie the second time, or is he really that incoherent?

Do we want @amirm to do DBT listening tests with music in his living room at 70 dB and call it a draw, or do we want him to run tests that check for relative quality of the gear, particularly as it relates to deceptive manufacturer marketing and relative prices?

 

[amirm]

I will set the gain of my system such that a 0dB signal would give a sound level of 120dB at 1m from my speakers, then listen to the signal without changing the gain.
That is the only way to tell whether it is audible or not.

Speakers are a different animal than headphones I used unless you have a very quiet listening space.

 

[GrimSurfer]

Do we want @amirm to do DBT listening tests with music in his living room at 70 dB and call it a draw, or do we want him to run tests that check for relative quality of the gear, particularly as it relates to deceptive manufacturer marketing and relative prices?

Since I likely don't have the exact same hearing as @amirm, nor live in his home, I vote for option two: measuring gear's performance and reporting how these correspond to manufacturer's published specs.

Besides anyone can do a DBT to accurately resolve issues of preference, whereas @amirm has the demonstrated skills and the necessary equipment to conduct objective measurement With a high degree of precision.

 

[digitalfrost]

Well look at that https://www.stereophile.com/content/book-review-99-true-almost-national-bestseller

99% True: Almost a National Bestseller, by Paul McGowan.

 

[GrimSurfer]

Well look at that https://www.stereophile.com/content/book-review-99-true-almost-national-bestseller

99% True: Almost a National Bestseller, by Paul McGowan.

That which is popular is very rarely true or accurate.*

(*More word games from PM. Truth is a binary concept, accuracy is a variable one.)

 

[ahofer]

As someone pushing a DBT for charity challenge, I recognize this concern. However, I don’t think anyone anticipates much uptake, so consumption of time is unlikely to change, at least from this effort.

The point of the challenge, from my perspective, is to set a line in the sand, a set of measured tolerances that describe electronics (and wire, and fuses) that cannot be told apart. To me there is a) value in defining those tolerances and b) an aspirational hope that someone can show us something new audible in a blind test.

The collateral benefit - when confronted by a condescending Golden Ear, Unmeasurable Audibles Troll, or Quantum Uncertainty Babbler, link to the challenge and watch him (yes, probably him) waffle helplessly before ignoring.

 

[ahofer]

99%

Well look at that https://www.stereophile.com/content/book-review-99-true-almost-national-bestseller

99% True: Almost a National Bestseller, by Paul McGowan.

99% Signal*, the Road to DAC Nirvana

*unless the signal is really quiet, then more like 50%

 

[GrimSurfer]

As someone pushing a DBT for charity challenge, I recognize this concern. However, I don’t think anyone anticipates much uptake, so consumption of time is unlikely to change, at least from this effort.

The point of the challenge, from my perspective, is to set a line in the sand, a set of measured tolerances that describe electronics (and wire, and fuses) that cannot be told apart. To me there is a) value in defining those tolerances and b) an aspirational hope that someone can show us something new audible in a blind test.

The collateral benefit - when confronted by a condescending Golden Ear, Unmeasurable Audibles Troll, or Quantum Uncertainty Babbler, link to the challenge and watch him (yes, probably him) waffle helplessly before ignoring.

I understand where you're going with this @ahofer, but there's no talking to these people on any kind of rational and mature level. They're residents of their own echo chambers or nihilistic towards everything but their own views.

Edit: Here's a good example of how people rail against stuff when they think there is a chance they might be wrong:

https://forum.psaudio.com/t/my-apologies-but-i-have-to-share-asr-s-review-of-the-sgcd/13310/122

It doesn't take many posts before a reasonable proposition is rejected and the topic locked by people with the most to lose reputationally.

 

[Michael_B]

I once got offered a product for review by a manufacturer on the condition I post it to Head Fi.

I reviewed it, as promised, but I put in absolutely ridiculously florid descriptions, bordering on audio porn, thinking of it as a troll and that the audience would see it as a bit of satirical writing.

To my surprise, the manufacturer was pleased and the audience took it sincerely.

Did you think the manufacturer was going to be displeased by a positive review?

 

[restorer-john]

Maybe a joke to you but I took the time to capture the tones and perform the ABX test and post the results. Not seeing any of you lifting a finger to advance our understanding of threshold of hearing.

And as I noted, there was no extra amplification. So don't go accusing me of corruption here without facts.

The results may be a surprise to you but wouldn't be to Fletcher-Munson after their 1933 listening test research to determine threshold of hearing:

View attachment 35470

You see the bottom set of curves where it says "threshold?" That is the lowest level tone we can hear. In the case of 1 kHz it is at 0 dB SPL. In the case of 3 to 4 kHz, it is actually -10 dBSPL (harmonic distortion of 1 kHz tone land here as does noise). If you pick a playback level of 110 dB, then the latter translates into 120 dB of dynamic range. In absence of TSS, and in quiet situation as in my closed headphones, you can hear such low level tones.

You need to get up much earlier than this to call my ethics into question.

Did you, or did you not, measure the playback reference level 0dBFS as 110dB SPL at the earphone/headphone (whatever you used) before you did your -120dB test? Or did you just turn up the volume until you could hear the tone?

 

[GrimSurfer]

I've read through the posts of @amirm, @Frank Dernie, and @restorer-john -- people whose views and professional competencies I deeply respect.

The issue, IMHO, isn't whether something is audible by @amirm just before the point of reaching a deafening level. It is whether it's reasonable to believe it would possibly be humanly audible within the context of what we know to be true from a scientific and medical standpoint. This is an objective and wholly defensible position that removes all sorts of variables out of the equation. It also eliminates any possibility of bias (I couldn't hear the noise with "brand x" but could with "brand y", even though their noise artifacts were of identical measurement).

This might seem like an unnecessarily inflexible objectivist position but is one that will avoid the worst outcome: the mere hint of bias affecting judgements or outcomes, thereby tainting the reputation of what this project seeks to achieve.

 

[AndrovichIV]

So if I am reading correctly he says that the aspects of his equipment that do not measure particularly well are not audible and are not a big deal, but that if he tried to make the equipment measure better, the gear would sound like "dog poo,” as does the better-measuring gear of some of his competitors.

To state the obvious, if, as he claims, the aspects of his gear that do not measure well (as compared to competitors) still perform well enough so as to be below audible thresholds, then making the gear measure better would not make it sound worse, or any different at all.

To paraphrase Uptain Sinclair, perhaps what appears to be a lack of understanding on his part is due to the fact that his livelihood depends on it.

Good catch. Logical impossibility he can claim that the deficiencies of his equipment are not audible, or that reducing them destroys the SQ, but he cannot claim both

 

[AndrovichIV]

Have you done your own listening test yet?

why is that relevant? What can we learn from such a test that Amirm could take?

 

[GrimSurfer]

why is that relevant? What can we learn from such a test that Amirm could take?

I like your way of thinking, @AndrovichIV. It reminds me of how the same discussion might play out in another engineering discipline:

Aeronautical Engineer 1: I have calculated that the airframe will withstand no more than 8g positive when flying without experiencing a catastrophic structural failure.

Engineer 2: Have you tried flying it beyond 8g in this configuration?

Engineer 1: No! Are you nuts?

Engineer 2: I'm quite sane, but we'll never know that 8g is the limit of the airframe until you fly it.

 

[AndrovichIV]

I understand where you're going with this @ahofer, but there's no talking to these people on any kind of rational and mature level. They're residents of their own echo chambers or nihilistic towards everything but their own views.

Edit: Here's a good example of how people rail against stuff when they think there is a chance they might be wrong:

https://forum.psaudio.com/t/my-apologies-but-i-have-to-share-asr-s-review-of-the-sgcd/13310/122

It doesn't take many posts before a reasonable proposition is rejected and the topic locked by people with the most to lose reputationally.

Surreal.

 

[amirm]

As expected:

Hmmm, it was serving their community quite well. It was not serving PS Audio or Paul.

Anyway, my challenge was not accepted. Paul must not have any charities he likes. $10,000 would have gone a long way for said charity and all Paul had to do is spend half hour, seeing if he can detect "dog poo" in other DACs.

Oh well, we will save that prize for some other person....

 

[GrimSurfer]

Hmmm, it was serving their community quite well. It was not serving PS Audio or Paul.

Co-rrect, Sir.

It's worth pointing out that I've seen you accused by folks on the PS Audio site of running a cult. Yet despite such claims, you let the discussion on MQA (something close to your heart on which I have no views one way or another) ride.

It is, therefore, curious that nary a peep occurs when PM shuts down a debate that challenges his interests.

This tells me that you either don't have business interests to protect or, if you do, you don't place them above scientific/technical truth of broader value to the community. My views on PM, however, are decidedly less generous...

 

[Soniclife]

why is that relevant? What can we learn from such a test that Amirm could take?

It was around the listening challenge he offered Paul, when he hasn't listened himself. This may well be very audible under controlled conditions.

 

[jaco61]

This all spots a lot of light not even to some defects of this PS product more so now in the personality of Paul himself. Oh no, this is pretty disgusting, to watch such proudness in ingnorancy spiced with an unecessary show of simple narcissism on top. Poa... with this reaction they are on best way on top of my not wanted list (still dominated by dog poo)