Amir and Blind Testing

Prof, with all due respect, Amir’s approach still assumes that he is measuring everything that matters in terms of ultimate sound quality. I think that is unlikely to be a valid assumption. If Amir’s assumption of perfect measurements is invalid, then the importance of human listening cannot be excluded from any evaluation of a product designed to improve the sound quality of reproduced music.

Amirm is coming to the question with knowledge about what type of distortion is possible, and what type of distortion is audible (given known thresholds of hearing).

If there is some OTHER form of distortion Amirm is not measuring for that would be audible...what would that be?

Shouldn’t PS Audio have identified just what that distortion was...if they even came up with a solution for it?

Yet PS Audio isn’t telling us they’ve identified some unknown type of distortion. They are saying their product fixes the AC power in standard ways that any engineer can understand...and test for! Which Amirm did. Amirm tested the effects of the regeneration on the power AND the effects with an amp hooked up.

What else could he possibly test? Simply waving at Some Mysterious Yet To Be Discovered thing no more helps PS Audio claims than it does anything at all.

As to Amirm not performing blind tests, I agree those would be a nice addition.

But given the objective evidence already showed distortion differences known to be inaudible, there isn’t any good reason to presume they’d be audible in blind tests.

PS Audio could, of course, always show otherwise. But we know they won’t. (The best inference being: because they couldn’t demonstrate any mysterious unmeasured audible distortion).

If there is some OTHER form of distortion Amirm is not measuring for that would be audible...what would that be?

I am pleased to inform you that the distortions coming from the room geometry, topology and acoustic content pairing with a specfic audio system is very powerful impediment to S.Q.... More powerful than comparison between relatively good electronic design subtelties measured by Amirm tools..

"Gear brand name subjective fetichist" like "tool objective measuring fetichist" ignore acoustic and psycho-acoustic and take the ears/ room to be unimportant way less than a decimal in THD+N amplifier specs for example...

This is called losing sight of the tree looking for an ant....

Yes it is useful to see an ant on a tree....But it is foolishness to never pay attention to the tree..

Distortions is not an electronical notion "per se" it is first and last a psycho-acoustical notion...Electronical design distortions concept come from the measured hearing human range perception and qualitative evaluation and subjective judgment guiding necessity ...

No piece of gear sound the same in different rooms...

An anechoic chamber is an experimetal room not a listening room..

There is no STANDARD room, all small room are different and own different acoustic positive and negative potential..

Then evaluation of an audio product not only is relative to human ears "specific" innate distortive potential working and history but related to specific room negative and yes, unbeknownst to most, sometimes to the positive effect of some distortions when they are controlled in some range and timing ratio for psycho-acoustic reason and experiment...

Acoustic is at least at the same level of complexity than basic electronic ...

I dont speak about common rule of placing acoustic panels on a wall here when i speak about acoustic... 😁😊I speak about something a bit more complex to say the least...Physical acoustic and psycho-acoustic of small room is not less complex than amphiteater acoustic architecture but in fact perhaps more complex because it must be designed for a specific audio system only and for the singular pair of ears of the owner room......

« Look at the tree on the back of  the walking ant »-Anonymus Zen monk

I'm ready glad that audio precision doesn't think like the objectivists on this forum, they actually think there is more or better measurements that can be performed in the future to better understand what we are hearing.

Amirm is coming to the question with knowledge about what type of distortion is possible, and what type of distortion is audible (given known thresholds of hearing).

If there is some OTHER form of distortion Amirm is not measuring for that would be audible...what would that be?

This is the problem I mentioned earlier. I do not believe that either Amir or the folks at PS Audio know exactly how all possible distortions (and time delays, phase changes, noise patterns, filter slopes, audible effects that change with frequency, etc.) interact to affect the sound quality the human brain hears and interprets. Thus,  SQ cannot be assessed using measurements alone. Listening must be part of the assessment. 

My summary of the P12 review on ASR is that Amir agrees that the P12 cleans up the waveform, as PS Audio intended, but that he can't measure any changes that he believes could improve the SQ when an amp is hooked up to the P12. Of course, Amir doesn't think listening is needed because he thinks his measurements tell the whole story. In contrast, PS Audio has measured and listened to the P12 during development of the product, and most users report hearing major improvements in SQ when using the P12, especially when there are significant problems with the power being supplied to the P12.

I do not believe that the folks at ASR are omniscient, and I also do not believe that the folks at PS Audio are trying to rip-off their customers.

This is the problem I mentioned earlier. I do not believe that either Amir or the folks at PS Audio know exactly how all possible distortions (and time delays, phase changes, noise patterns, filter slopes, audible effects that change with frequency, etc.) interact to affect the sound quality the human brain hears and interprets. Thus, SQ cannot be assessed using measurements alone. Listening must be part of the assessment.

Great post indeed! thanks very much....

And particularly these 2 lines...

I do not believe that the folks at ASR are omniscient, and I also do not believe that the folks at PS Audio are trying to rip-off their customers.