The meaning of measurements

[KeithR]

Hi Keith


I heard the ML 2.1 (which I owned) with the ML3 shortly after Vlad released it in my sound room. There is a "magic" about the ML3 that the 2.1 didn't have. It's a very holographic image. Keith you were planning to hear my ML3 with a buddy of yours. Let me know when.

have no doubt it sounds better. and in fact- I take back my statement as the measurements are a bit hard to read on the Zinio version, so perhaps will be easier once uploaded to Stereophile.com with full graphs.

 

[Ron Party]

You need, more particularly, a set of speakers that match the room they are in. Now, I do not mean that a particular set of speakers can rescue a bad room, sorry, no, nothing but treatment or worse will fix a bad room. Electronic correction does not fix bad rooms to any great extent, the best use for it is making a pretty good room great.

But in addition to that, you need a set of loudspeakers with an off-axis radiation pattern that works with the room, and with the listener's expectations and tastes. This is, by itself, one of the reasons that there are so many loudspeakers and so much argument about them, in short, what somebody wants in speakers is in part personal taste. And personal preference is just that, personal. No more, no less.

Finally, the idea of "holographic sound" from 2 speakers is only going to work in a very limited sense with a small number of recordings, again of the listener's expectation and taste, with a particular setup of a system in a particular room with particular speakers. The important parts are room, speakers, recording, and then everything else about 2 orders of magnitude or more down the scale in importance, and notice that of the 3 most important, all of them are affected intensely by personal taste.

I hope my point is starting to come out by now, yes?

The idea of true holography is called "wave field synthesis", which is in fact something that people do work on. It's kind of expensive, requires very, very custom recordings with very custom systems in a custom designed room and something like a minimum of 128 channels for the desired effect. At low and mid-frequencies, these systems do something akin to holography. They sound quite real, I've heard a few of them. The problem is that they sound, sometimes, too real, do you really want to know about the problems in the recording space? No, probably not.

There are systems, including one I've invented and worked with (there are a few, mind you, not just that) that attempt to capture perceptual cues, as opposed to soundfield (analytic) cues. They suffer from the same problem, in particular, they suffer from being too accurate sometimes. Somewhere out there, you can see some of the reviews for the system I worked on, but I don't have them at my fingertips at the minute. Good reviews. BUT they also require changing the whole production chain, and require 5.0 (i.e. 5 full range speakers) playback, or better 7.0. Not a bunch of little speakers and a couple of big ones, full ranged matched speakers all around.

But the real problem is production, either of concert captures (i.e. classical in-situ), or of synthetic studio production.

There is myth that ensures it won't work (i.e. don't use the center speaker, when it is in fact the most important, as shown in 1933 by some very basic work in soundfield perception), there are cinema production rules (which are right for cinema, Holman is a smart guy, but they are terribly wrong for home theatre or for hi-fi use), and a persistence of the "phantom center" which ensures that the most important features of multichannel of any sort can not work.

The sad part is that work before 1940 showed quite a bit of this, and convincingly, but we're still doing things in the modern way. (Yes, that is intentional irony.)

We have people arguing, for instance, that using time-delay panning as well as amplitude panning doesn't work, based on some older work that used time delays of 5, 10, 15, 20 milliseconds, which obviously won't work unless your head is 5, 10, ... FEET across.

So, there is a lot known about how to establish a good, convincing synthetic soundfield using perceptual principles, or doing it the hard way, and actually reproducing, at least in a 2-d way, the actual soundfield, but the market penetration is going to be a very, very tough issue, because it requires revising every step of a chain fraught with both science and myth, as well as what seems to me to be some deliberate misinformation here and there.

Hi j.j.

Very interesting information. Thanks. Over 3 years ago I started a thread on wave field synthesis but all I got in return was some cute trigonometry humor.

 

[NorthStar]

Awesome Ron!

* I'll do my very best to resuscitate (resurrect) it. ...Gimme some time (research).

Holographic Sound is seriously worth exploring (Wave Field Synthesis).

 

[RogerD]

I came across this Stereophile interview mentioned earlier.

VS: I had been working for a long time on the question of why one piece of equipment makes good sound and the other does not. This question is as old as the world itself. I took the path of psychoacoustics and developed a number of mathematical models which manifested a more or less close approximation to reality (fortunately, back in Russia, I had a whole R&D department at my disposal). Those mathematical models were described by differential equations; specific correlation systems were developed. Using this information I obtained the electronic models of processes.

AM: In other words, you created something akin to the analog computer?

VS: Correct. As a result, I ended up with a very limited number of topologies which can be used in audio applications. Now I make audio equipment using those results. As a rule, I do not go through listening tests of the designs I create: when design is finished I make one listening test for control purposes...

AM: Simply speaking, you know the results beforehand?

VS: I do. Each model is designed absolutely deliberately with predetermined and predictable characteristics.

http://www.lammindustries.com/INTERVIE/audiorus.html

My take all the top designers use mathematical models for their circuit design. I know my SS amps were designed using a form of FHT analysis. Knowing the designer "he" knew well before hand how the amplifier would sound. As for measurements I think they matter most to the reviewers historically and consumers,but less to some designers.

 

[NorthStar]

So, measurements were done even before the building process, then a simple listening test for confirmation.

That tells me that no matter what measurements are/were performed afterwards, the reality is that most good audio designers already imprinted their "sound" into their designs (audio gear, loudspeakers, etc.).

Great perspective on after measurements, from Stereophile and the gang. ...Means not much at all.
And on top of that if we cannot trust our own ears how can we trust the reviewer's ears?

 

[Phelonious Ponk]

I came across this Stereophile interview mentioned earlier.

VS: I had been working for a long time on the question of why one piece of equipment makes good sound and the other does not. This question is as old as the world itself. I took the path of psychoacoustics and developed a number of mathematical models which manifested a more or less close approximation to reality (fortunately, back in Russia, I had a whole R&D department at my disposal). Those mathematical models were described by differential equations; specific correlation systems were developed. Using this information I obtained the electronic models of processes.

AM: In other words, you created something akin to the analog computer?

VS: Correct. As a result, I ended up with a very limited number of topologies which can be used in audio applications. Now I make audio equipment using those results. As a rule, I do not go through listening tests of the designs I create: when design is finished I make one listening test for control purposes...

AM: Simply speaking, you know the results beforehand?

VS: I do. Each model is designed absolutely deliberately with predetermined and predictable characteristics.

http://www.lammindustries.com/INTERVIE/audiorus.html

My take all the top designers use mathematical models for their circuit design. I know my SS amps were designed using a form of FHT analysis. Knowing the designer "he" knew well before hand how the amplifier would sound. As for measurements I think they matter most to the reviewers historically and consumers,but less to some designers.

And the irony dangled over the board with the dark weight of hanged men.

Tim

 

[JackD201]

Boy, seems like everybody using simulators like SPICE must be wasting their time eh? Let's all go back to stone tools.

 

[Phelonious Ponk]

Hi j.j.

Very interesting information. Thanks. Over 3 years ago I started a thread on wave field synthesis but all I got in return was some cute trigonometry humor.

If ever there was an oxymoron.

Tim

 

[Groucho]

Some people have the knack of sounding modest, interesting, impressive and knowledgeable in an interview. Some don't.

 

[JackD201]

Some don't have the knack anywhere.

 

[jkeny]

Boy, seems like everybody using simulators like SPICE must be wasting their time eh? Let's all go back to stone tools.

Yea & Spice doesn't even model real-world components with accuracy!

 

[microstrip]

I came across this Stereophile interview mentioned earlier.

VS: I had been working for a long time on the question of why one piece of equipment makes good sound and the other does not. This question is as old as the world itself. I took the path of psychoacoustics and developed a number of mathematical models which manifested a more or less close approximation to reality (fortunately, back in Russia, I had a whole R&D department at my disposal). Those mathematical models were described by differential equations; specific correlation systems were developed. Using this information I obtained the electronic models of processes.

AM: In other words, you created something akin to the analog computer?

VS: Correct. As a result, I ended up with a very limited number of topologies which can be used in audio applications. Now I make audio equipment using those results. As a rule, I do not go through listening tests of the designs I create: when design is finished I make one listening test for control purposes...

AM: Simply speaking, you know the results beforehand?

VS: I do. Each model is designed absolutely deliberately with predetermined and predictable characteristics.

http://www.lammindustries.com/INTERVIE/audiorus.html

My take all the top designers use mathematical models for their circuit design. I know my SS amps were designed using a form of FHT analysis. Knowing the designer "he" knew well before hand how the amplifier would sound. As for measurements I think they matter most to the reviewers historically and consumers,but less to some designers.

IMHO the most interesting part of Vladimir Lamm thought provoking interview for this thread is the part where he refers to formal measurements. He shares an opinion that I have seen implicitly referred by other designers - once you master the topology and understand well its implications in sound quality, the formal measurements can be correlated with sound quality.

 

[RogerD]

IMHO the most interesting part of Vladimir Lamm thought provoking interview for this thread is the part where he refers to formal measurements. He shares an opinion that I have seen implicitly referred by other designers - once you master the topology and understand well its implications in sound quality, the formal measurements can be correlated with sound quality.

Here is the explanation for the science and methods used for my Agtron Platinum monoblocks in 1994, The designer Carl Staub knew exactly how the amplifier would perform before hand.

FHT is the name for the high-resolution,time domain circuit modeling used exclusively in the design of each Platinum component.
With FHT,there is now a scientific systematic approach to satisfying the critical demands of high end audio enthusiasts.

FHT allows the iterative analysis of circuit behavior in response to dynamic and spectral pseudo random simulation.It quantifies and analyses the effects of such things as dielectrics,dissipation,inductance,hysteresis,differential nodal transfer characteristics,and group distortion effects with resolution to 1 x 10-12

The result is a level of accuracy and integrity that would otherwise be unobtainable with conventional design /testing methodologies. Agtron manual 1994

 

[mep]

Some don't have the knack anywhere.

I used to have the knack on LP, but my dog ate it.

 

[JackD201]

I used to have the Kinks but..........nevermind!

 

[Phelonious Ponk]

I used to have the knack on LP, but my dog ate it.

The Knack...I miss power pop. Pop has no power over me anymore. The Knack, Elvis Costello, The Smithereens, The BoDeans...when men were men and pop was powerful...sigh...

Tim

 

[Steve Williams]

Post deleted

Now back on topic.

 

[DaveyF]

Here is the explanation for the science and methods used for my Agtron Platinum monoblocks in 1994, The designer Carl Staub knew exactly how the amplifier would perform before hand.

Interesting, Roger. However, given the numerous variables that one has to contend with in a system, like the type of speaker's paired with the amp, the room, the type of music preferred by the listener, the type of front end, the volume level that the listener prefers to listen at, the ancillary cabling and on and on; I do NOT see how anyone can really know for sure what their amp will sound like in the "typical" listener's system. Perform as to the measuring devices used, that's another discussion altogether!

 

[RogerD]

Interesting, Roger. However, given the numerous variables that one has to contend with in a system, like the type of speaker's paired with the amp, the room, the type of music preferred by the listener, the type of front end, the volume level that the listener prefers to listen at, the ancillary cabling and on and on; I do NOT see how anyone can really know for sure what their amp will sound like in the "typical" listener's system. Perform as to the measuring devices used, that's another discussion altogether!

I disagree. Here on WBF there is atleast thousands of pages written on measurements,from everthing to soup and nuts. So why would it be so far off base for a electronics engineer like Lamm or Staub who understand the science so completely to have correct expectations on the signature sound of their design. If you ask me,mere mortals like us don't comprehend such a gifted intellect as those who build and design such ground breaking gear.

 

[j_j]

I disagree. Here on WBF there is atleast thousands of pages written on measurements,from everthing to soup and nuts. So why would it be so far off base for a electronics engineer like Lamm or Staub who understand the science so completely to have correct expectations on the signature sound of their design. If you ask me,mere mortals like us don't comprehend such a gifted intellect as those who build and design such ground breaking gear.

Could you explain just how the existence of "thousands of pages" of discussion on an internet forum proves much of anything?

Or was that sarcasm?