PTE’s Blind Tests

Jim Rush of PTE (Precision Transducer Engineering) of Orange, CA explained that he was using the system in his room, headlined by PTE’s The Phoenix self-powered, bi-amplified loudspeaker ($5700/pair), to conduct 10 different blind tests with five sequences. The results of his experiments, which he said demonstrated that most people couldn’t discern differences with a high degree of accuracy, are slated to be posted to PTE’s website.

In the test I witnessed from the sidelines, attendees were asked to distinguish an analog source from a digital copy made using Antelope Audio ultra high-resolution electronics. Besides the highly accurate The Phoenix, the rest of the equipment chain consisted of a George Warren turntable outfitted with a Graham 2.2 arm and Soundsmith Hyperion cartridge, PTE’s MM/MC-R phono preamp ($1595) and a T+A 2030R preamp.

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JohnnyR's picture
Did You Run Screaming.........

......from the room afterwards talking about blind tests? I know how they make you so upset and all. Of course YOU didn't participate.....silly me for asking.

mrplankton2u's picture
HOW DARE HE!

This guy has the nerve to challenge golden eared audiophools on the glorious merits of pops, clicks, wow, and flutter???

The high end has been boxing itself into a corner (sadly, no help from Stereophile) much like James Inoffe has been proclaiming that huge increases in atmospheric CO2 are natural and that global warming is a hoax.  Utlimately, purveyors of $100,000 speaker wire, "harmonizers", electricity "conditioners" and the like are going to find there aren't any more suckers...ahem I mean customers that are willing to pay for their particular brand of marketing BS. Credibility is hard to build up and maintain and easy to destroy. Stereophile may feel in the short run that it needs to keep presenting the ridiculous, unproven claims for interconnects/wires, tube amps, analog sources, battery powered digital devices and the like as fact in order to keep the lights on and pay for "journalists" to travel from show to show. In the process, it is turning away the  majority of people who might otherwise participate in a quality focused marketplace in favor of the select few freaks that don't have a legitimate appreciation for real quality and support of industry state of the art. Merit is replaced with marketing hype and con games. Science and objectivity is diplaced by belief and cronyism. There are a few folks that have been in the business for a long time who have recognized this trend and spoken out about their concerns. Unfortunately, the folks at Stereophile are not in that camp.

Btw, I'm curious what cables Jim was using and what was the impression of the system's performance according to Mr. Serinus. A cursory look at Serinus' other blurbs at RMAF include the usual accolades and list of high priced "accessories". Why no mention of his impression of Jim Rush's system performance? Did he think we wouldn't notice? Are we all supposed to be that stupid? 

When I think of the current "high end", I'm reminded of some lyrics from a favorite old song:

"And then you get an artist says he doesn't want to paint at all

He takes an empty canvas and sticks it on the wall

The birds of a feather all the phonies and all of the fakes

While the dealers they get together

And they decide who gets the breaks

And who's going to be, who's going to be

In the gallery." - Mark Knopfler

JohnnyR's picture
No Reply

Sorry but as you can see, you won't get a serious or any reply for that matter from Stereophile if you bring up REAL points for consideration.

kev313's picture
point

JohnnyR, Why waste so much energy if you do not like anything about the world covered by Stereophile?

GeorgeHolland's picture
I saw a few things he liked

I saw a few things he liked but also he was asking some serious questions in his own way. Like why himself and mrplankton2u never got a serious reply. I'd be curious to know also. I think it's wonderful that blind tests were done in this situation and wonder why Stereophile doesn't use them at all

jimrush's picture
Blind Tests

Without acrimony I just wish to say that blind tests are stressful and enlightening. Many of us think we can hear  things that seem to evaporate when we are put to the test.

I wish to thank the brave audiophile souls who participated in our test and issue a challenge to others who think that they hear improvements with fancy power cables.

If you can really hear these differences then you should be able to tell which power cord  is playing 8 times out of ten. We tried this at the show and we could not hear any difference on a repeatable basis. The over $1000 power cables in question will not be named here.

Before you decide that I am just deaf, try it for yourself. And if you can hear it please post it somewhere on the web, I have not been able to find any such evidence.

Happy listening

Jim Rush

mrplankton2u's picture
Thanks For Your Commitment To Honesty And Candor!!

I haven't heard your speakers yet. But given how you've defined yourself in this instance and knowing a little about how your speakers are put together from other's investigations, I would highly recommend that folks in the market for a good solid powered stand monitor consider your Phoenix.  I'm personally familiar with the Peerless drivers you've used and they produce top notch sound. 

Thanks Jim!

GeorgeHolland's picture
Thank you Mr Rush for

Thank you Mr Rush for bringing reason and into a world that is increasingly being filled up with subjective blather and sillyness, I'm sure you made a few enemies among the cable faithful but that's to be expected when you proclaim the earth really isn't flat.

GeorgeHolland's picture
Mr Rush, has JA or Mr Serinus

Mr Rush, has JA or Mr Serinus come by again and try out your blind tests? I invited them to do so but I feel deep down that it is a lost cause getting them to take it seriously. Always some excuse why they won't or can't. I suppose they aren't really serious about real testing. Let us know if they do however, thank you.

John Atkinson's picture
A Matter Of Timing

GeorgeHolland wrote:
Mr Rush, has JA or Mr Serinus come by again and try out your blind tests? I invited them to do so but I feel deep down that it is a lost cause getting them to take it seriously.

The show, and with it Mr. Rush's tests, ended in Sunday October 14; you are asking your question on Saturday October 20, Mr. Holland. Without Jason and I having access to a time machine, your question is moot.

As I pointed out to you earlier today, I have actually taken part in a large number of formal blind tests over the past 35 years. While many of those tests produced results no different from chance, others did show that I could distinguish the components by ear under blind conditions to the accepted standards of statistical significance.

And again I ask you what formal blind tests have you organized or taken part in to be so sure of their efficacy?

John Atkinson

Editor, Stereophile

GeorgeHolland's picture
You keep saying you have done

You keep saying you have done blind testing so lets see those published results? Anyone can say they did but the proof is in the showing there of. The snarky attitude is showing again Mr Atkinson, any wonder people don't post much on here asking valid questions? All the Stereophile staff seem to have a chip on their shoulders just waiting to pounce on anyone that doesn't agree with them. So much for civility.

jimrush's picture
The results are posted

I have tabulated and posted the results of our listening test, and it appears to me that there was an audible difference, although it clearly was not heard by all.  I think that as digital continues to get better and better the price of digitizing records will come down, and listening tests will be a useful way of determining when it is good enough.

Here are the results  http://www.pteacoustics.com/pte_demo1_011.htm

I want to defend Stereophile here: It is a lot of work to make all the measurements that are presented in the magazine. Whatever you may think about the long descriptions of sound, they are still very important for loudspeakers because we do not have a measurement for things like imaging specificity.

I also want to encourage audiophile societies to do some listening tests. This will help us all to see if the emperor has new clothes on or not.... BTW it can be fun.

Let's all light a candle and see what we can here.

Jim Rush

John Atkinson's picture
Statistics

jimrush wrote:
Here are the results  http://www.pteacoustics.com/pte_demo1_011.htm

Thnaks very much for posting the results, Jim. Unless I am misremembering, 94 correct out of 160 trials means that there was less than 1% possibility that the results were due to chance alone, ie, there was indeed a real, if small, audible difference. That doesn't necessarily mean that this was due to the digitization; there may have been interfering variables like a slight level difference or an absolute polarity inversion. Not having been present for the test, I don't know if there was or not, so more information on the test conditions will be welcome.

jimrush wrote:
I want to defend Stereophile here: It is a lot of work to make all the measurements that are presented in the magazine.

Thank you. Yes, the measurements are resource-intensive. Each set of published measurements represents a day or more of my life!

jimrush wrote:
Whatever you may think about the long descriptions of sound, they are still very important for loudspeakers because we do not have a measurement for things like imaging specificity.

This was one of things I dsicussed in my preseations at RMAF: Imaging specificity is a property of the brain's internal constructs and by definition can't be measured.

John Atkinson

Editor, Stereophile

mrplankton2u's picture
WRONG!

If you continue to maintain that aspects of sound imaging between a pair of stereo speakers cannot be measured, you will place yourself on the wrong side of history. Highly regarded, successful people like Floyd Toole and Sean Olive who've devoted their professional careers to researching these issues have set forth loudspeaker performance criteria that improve aspects of the sound wavefronts which produce a more focused stereo image. We know from the blind tests these people have conducted and from the work of many others in the acoustics and psychoacoustics field that the ear brain combination rely on specific cues relating to absolute timing of sound pulses, phase aberrations (relative timing), and the impact of left to right amplitude differences as frequency is varied. This is proven science which bears directly on real world design criteria such as adherence to uniform frequency response, constant directivity, and measures taken to avoid problematic room interaction. The science has spoken and it has spoken very clearly to those who are patient and engaged enough to listen. The successful double blind tests conducted in the past have shown that better design approaches taking the above aspects into account has resulted in a loudspeaker that throws a more stable, focused sound image. PERIOD!

Thanks Jim for sticking with science and the scientific method - particularly on these thorny issues.

John Atkinson's picture
Science?

mrplankton2u wrote:
highly regarded, successful people like Floyd Toole and Sean Olive who've devoted their professional careers to researching these issues have set forth loudspeaker performance criteria that improve aspects of the sound wavefronts which produce a more focused stereo image.

You must be aware that Sean Olive and Floyd Toole's blind testing of loudspeakers was primarily performed in mono. But I am not wrong on the nature of stereo imaging. While you can measure the behavior of the soundwaves reaching the ears and project from those measurements what the likely effect will be, you cannot measure the quality of the stereo image itself, which is an internal construct, ie, an illusion.

This was the thrust of my Richard Heyser Memorial Lecture that I was invited to give to at the 2011 AES Convention.  You can download the preprint from www.yousendit.com/download/WUJiaXRBQ3RtMEpDaDhUQw. I request you to read it before continuing with your comments.

John Atkinson
Editor Stereophile

mrplankton2u's picture
Science? - Yes, SCIENCE, not MYSTICISM..

The lengthy "lecture" you linked to is totally irrelevent to the issue at hand - the simple question as to whether or not technology exists to accurately measure the deleterious effects of a loudspeaker on the signal fed to it - specifically where the "integrity" of the stereo image of the signal pair is concerned. Your preoccupation with "negative frequencies" demonstrates little more than your struggle to understand the difficulty in approximating the continuous time real world with discrete time methods as represented in the limitations of mathematical constructs such as the Lapalace and Fourier transform. The only valueable or useful lesson one can readily derive from that distraction is that  we now have the means to achieve the level of precision (bandwidth) and noise rejection to physically and repeatedly render signals to a higher degree of accuracy than the human ear and brain combination can detect. Machinery that can detect and accurately record softer sounds and wider bandwidths than the human ear/brain combination has been with us for a long, long time.

In this comment section and elsewhere, you appear to be engaging in a consistent pattern of conflating that which can be measured and recorded - with the human brain's response. Clearly, traditional stereo is a poor approximation of an original sound from an original source with two sources of sound - and all the challenges/problems that entails. This however does not mean we cannot isolate the loudspeaker's role in advancing the signal and determine where it is succeeding or failing in the chosen approach we've come to know as "stereo". It's like suggesting that since time travel has not yet been achieved, there is no point or capability to improve (dare I say - "perfect") the design of turbofan jet engines. Will a quieter, more efficient, and more powerful jet engine be a welcome change and a goal worth pursuing? Absolutely. Do the folks at Pratt and Whitney or GE throw their hands in the air and give up because they haven't figured out how to make a jet liner travel at the speed of light? Obviously, no. They keep measuring that which can be measured and make improvements/adjustments. 

You said above:

" you can measure the behavior of the soundwaves reaching the ears and project from those measurements what the likely effect will be, you cannot measure the quality of the stereo image itself, which is an internal construct, ie, an illusion."

To that I say,

No one is suggesting we can or need to see if the current stereo method of processing sound is capable of producing a "perfect" or acceptable "internal construct" or "illusion". We know the answer. We also know the Fourier Transform is a less than perfect discrete approximation of a continuous phenomenon. We also know that jetliners aren't space or time travel machines However, these readily discernible facts don't prevent us from advancing the state of the art in either pursuit. Just as with stereo, how well we're doing CAN be measured and how well we achieve our goals is not an illusion - despite the fact that the goal itself is ultimately an illusion and the chosen method for achieving the goal at the outset was less than perfect or in some ways and to some extent - doomed to failure. As noted elsewhere, the goal of reproducing what is experienced at the entrance of each ear canal in a live musical event is not mysticism or technically out of reach. We've chosen a less than perfect method for getting to the end game And frankly, we don't need to concern or distract ourselves with how each person's brain or head transfer function impacts the utlimate sound image they form. We are so very far from worrying about that given the current paradigm.

John Atkinson's picture
Thank You

mrplankton2u wrote:
The lengthy "lecture" you linked to is totally irrelevent to the issue at hand - the simple question as to whether or not technology exists to accurately measure the deleterious effects of a loudspeaker on the signal fed to it - specifically where the "integrity" of the stereo image of the signal pair is concerned.

At least you read the preprint of my lecture, even if you didn't understand it. :-)

Let me try again: If a tree falls in the forest, does it make a sound if there is no-one there to hear it?

John Atkinson

Editor, Stereophile

mrplankton2u's picture
Perhaps you haven't yet heard...

Your age and lack of understanding is starting to show. That age old question has been deemed irrelevent. The new important (2 part) question which has supplanted it in the digital age is

 

If the sound of the wind through the trees has "negative frequencies", can you hear them? And if so, do they cancel out the "positive frequencies"?

 

John, I learned about "negative frequencies" in a well known university about 30 years ago. Despite the failings of your attempt to "lecture", it was a good read nonetheless. Thanks.

JohnnyR's picture
Wow John is All Wound Up..........

His "lectures" aren't all that based upong science or facts for that matter. I recall a certain "lecture" he gave on digital jitter that promptly got criticised from just about anyone that really knows the subject. His grasp on reality just isn't all that great.

mrplankton2u's picture
Now, Now..

Now, now, Johnny - perhaps we should give JA the benefit of the doubt. My hunch is that JA has just started listening to the special sounds of a new band that just hit the New York scene... They call themselves - the Dirac Delta Function 

Catchy name, huh?

: )

jimrush's picture
Imaging and Measurement

John Is right here guys:

The interaction of the Louspeaker the room and the human mind is incredibly complicated, and the illusion of reality is an experience of the human mind.

Can we measure everyting we can hear? No. Just trying to make a microphone -preamplifier combination with the dynamic range of human hearing is not possible as far as I know.

Rememer that the loudspeaker has a 3 dimensional radiation pattern. Unless you are willing to make an infinite number of measurements you do not really know all that is going on with the radiation patter of a loudspeaker.

Add to this the way the room interacts with all this and it's fair to say that imaging cannot be condensed into a single measurement.

Here are some measurable quantities that do contribute to good imaging:

Stereo matching. The better the channels match the better the imaging:

Wide horizontal dispersion. As John has observed with many measurements and listneing experiences.

Low cabinet acoustical output. The radiation from the cabinet leads the ear to localize the loudspeaker spoiling the dissapearing act of a good loudspeaker. This can be inferred from accelerometer measurement.

Rapid risetime. I am submitting this without proof, just many years of loudspeaker design and listenting.

Let's all be civil to each other.

Jim Rush

 

 

 

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