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measurements are models - Page 6

post #76 of 93
Quote:
Originally Posted by raddle View Post
 

The reason I think it's important to understand measurements as models is this: I think there are certain phenomena that the current state of sound science fails to explain. I think that sound science is consistent-- it's a set of observations and theories that reinforce each other. I think it has holes, however.

 

But first I'm finding it hard to believe that anyone would think FR is not a model. I'm interested in the reality of how it is used and measured. Apart from that, it's just meaningless numbers.

 

However, I think that I've been a little too rigid about defining "models" and indicating how they are used. I admit there are a lot of ways that models are used and defined, but this doesn't change my point about FR.

 

I would be interested in how people here would answer the question: "Why do we measure FR?"

 

Besides that I'll note that FR models a device as linear and can be used to predict its response to future signals that have not been previously measured, although not with perfect accuracy.

 

Which phenomena are the ones that aren't explained? Where do the holes show up? How do you know there are holes? Can you demonstrate or elaborate on them? If you're talking about unexplained perceptual phenomena then many of these things claimed are unproven. It is impossible to know with 100% certainty whether they are real in the sense that many people think they are (some difference in sound output causes a perceptually different response) or just a product of psychological biases and other nuisance factors. Until the former is proved we tend to think the latter is more likely in many cases. When you furthermore talk about perceptual accuracy, this is a moving target and varies from person to person.

 

 

The Fourier transform or the measurements may or may not be models (okay, we can call them models if you want). If we claim a certain device has a certain frequency response then implicitly we have characterized its performance with a model, yes, which has known limitations for accuracy. We measure FR because for many systems it provides good predictions of systems behavior with a range of untested inputs. Anyway, that is why, if necessary, additional and more accurate models are used.

post #77 of 93

The phenomena that science fails to explain is the way subjectivism can make people fight to the death over things that are easily disproven.

post #78 of 93
Quote:
Originally Posted by raddle View Post
 

I would be interested in how people here would answer the question: "Why do we measure FR?"

 

To calibrate the volume level of each frequency in the range of human hearing to make sure that our reproduced sound exactly matches the intended sound. In short, to guarantee that what we hear in our homes is the same as what the engineers who recorded the sound intended. The closer you can get to calibrated, the more fidelity to the original.


Edited by bigshot - 1/8/14 at 11:23am
post #79 of 93
Quote:
Originally Posted by bigshot View Post
 

 

To calibrate the volume level of each frequency in the range of human hearing to make sure that our reproduced sound exactly matches the intended sound. In short, to guarantee that what we hear in our homes is the same as what the engineers who recorded the sound intended. The closer you can get to calibrated, the more fidelity to the original.

Based on the other thread the OP started; http://www.head-fi.org/t/698421/why-im-a-subjectivist, I believed what the OP trying to say is FR cannot predict his cable listening, therefore it is useless. Instead of trying to explain his perceived difference, he is trying to just discredit measurement as a "model". This will explain all the micro-mechanism and holes that he claimed is missing in science.

post #80 of 93

That thread makes no sense. Fidelity and accuracy are easy to determine. That's what measurements are for.

post #81 of 93
Quote:
Originally Posted by dvw View Post

Based on the other thread the OP started; http://www.head-fi.org/t/698421/why-im-a-subjectivist, I believed what the OP trying to say is FR cannot predict his cable listening, therefore it is useless. Instead of trying to explain his perceived difference, he is trying to just discredit measurement as a "model". This will explain all the micro-mechanism and holes that he claimed is missing in science.

Sometimes I feel sad for people who've spent a lot of time and money, and their entire experience consists of a mixture of some obvious scientifically valid conclusions, and a lot of subjective opinion.
Its not only in this forum, plenty of other scenarios and fields.
Some just don't want to start with the theory of a topic, others simply haven't had a chance.
But now since they've put in so much time and effort, they obviously will defend that experience. Imagine someone telling you that most of your life experiences are invalid....

A tough situation. No wonder ignorance is bliss.
post #82 of 93

For the life of me, I can't see how you can possibly achieve a high level of quality without following the fundamental principles of sound to build your system. People who assume that a high price tag equates with high quality are basing their systems on something other than audio fidelity.

post #83 of 93

I don't know if ignorance is bliss, but it sure helps a lot of people going against some fundamental laws of physics with a straight face.

post #84 of 93

Ignorance is simply not knowing. Stupidity is refusing to know.

post #85 of 93
Thread Starter 
Quote:
Originally Posted by dvw View Post
 

Based on the other thread the OP started; http://www.head-fi.org/t/698421/why-im-a-subjectivist, I believed what the OP trying to say is FR cannot predict his cable listening, therefore it is useless. Instead of trying to explain his perceived difference, he is trying to just discredit measurement as a "model". This will explain all the micro-mechanism and holes that he claimed is missing in science.

Ding ding! You win the prize for first one to drag cables into the discussion. Look, we can limit this discussion to speakers with known audible differences.

post #86 of 93
Quote:
Originally Posted by raddle View Post
 

Ding ding! You win the prize for first one to drag cables into the discussion. Look, we can limit this discussion to speakers with known audible differences.

I don't know what it is you are trying to discuss. Are saying two speakers measuring the same can sound different or two speakers measured different can sound the same? Is this a modelling you're talking about? If so please illustrate how that works?

 

There are lots of work done on simulated accuracy on amp. The most famous being Bob Carver's tube amp challenge. They're all based on same measurement on different equipment. I would love to see an example where same measurement can produce different result.

post #87 of 93
Thread Starter 
Quote:
Originally Posted by dvw View Post
 

I don't know what it is you are trying to discuss. Are saying two speakers measuring the same can sound different or two speakers measured different can sound the same? Is this a modelling you're talking about? If so please illustrate how that works?

 

There are lots of work done on simulated accuracy on amp. The most famous being Bob Carver's tube amp challenge. They're all based on same measurement on different equipment. I would love to see an example where same measurement can produce different result.

Since measurements are incomplete models of a systems behavior, then two systems which measure the same can behave differently. Is a misconception common among objectivists that measurements completely characterize the behavior of the system; that is, a misconception that measurements can predict the output of the system for all possible future inputs.

post #88 of 93
Quote:
Originally Posted by raddle View Post
 

Since measurements are incomplete models of a systems behavior, then two systems which measure the same can behave differently. Is a misconception common among objectivists that measurements completely characterize the behavior of the system; that is, a misconception that measurements can predict the output of the system for all possible future inputs.


for once I will agree with you (open a bottle of champagne we need to celebrate this). if you take only a frequency response graph for example, you can have 2 things with a pretty damn close signature that will not sound the same. because of distortion or delays or reverb or just because both graphs were smoothed so the differences might have been erased then?

but the more complete the analysis the more it would become enigmatic to encounter 2gears measuring the same and behaving differently. 

I agree again that people tend to set in stone what a given phone will sound like and often forget about the various effects a given source can have on it. but if the system follows the requirements of the measurements, then the result will be mostly known. that 's why we lab rats tend to find very important to know our impedances and power. it would be silly of me to decide upon a multi BA IEM based on measurements, and then plug a 22ohm ak100 into it. there is a 100% chance that the sound will not be what I expect.

whatever thing you call model works only in the intended situation, I believe that's a given. but you are right, the way we manipulate measurements in audio forums tends to dismiss that fact so predictions can be wrong.

but in the end it's not the model's fault, the human using the results out of context is the guilty part of measurements.

post #89 of 93
Quote:
Originally Posted by raddle View Post

Since measurements are incomplete models of a systems behavior, then two systems which measure the same can behave differently. Is a misconception common among objectivists that measurements completely characterize the behavior of the system; that is, a misconception that measurements can predict the output of the system for all possible future inputs.
Where are these 'objectivists' who say a measurement completely characterises the behaviour of a system? Can you show how this 'misconception' is 'widespread'?
Are they the same objectivists who allegedly sit there all day recording impulse responses and calculating FRs and never actually listen to their equipment?

This forum has low tolerance for trolling, don't try.
Edited by higbvuyb - 1/12/14 at 6:36am
post #90 of 93

What are any examples of two things measuring the same on decent equipment (with the relevant-to-audio-and-usage performance metrics measured; if you're talking just FR of course that's not enough) where people are able to distinguish them reliably based on the sound? Are there any where there is little reasonable doubt that there weren't confounding variables or other factors leading to a positive result (detection)? I've asked this multiple times over the years but never get examples back. If it exists, this is where the science can stand to be improved. I mean, in the past there were aspects people didn't realize to measure for, for example. 

 

There are many examples of things measuring different but sounding the same, especially with differences small, but that in of itself is not a guarantee about whether things can sound different but measure the same.


Edited by mikeaj - 1/12/14 at 9:12am
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