Originally Posted by dragonfyr
So when is someone going to jump out and tell we have all been punked by someone simply pretending to know what he is talking about?
Welcome to the lastest installment of: :
Operator Mistakes Can Lead to erroneous data which can be further compounded by the clueless interpretation of said wacked data! DUH!!!!!
Bigus, when you stop and recognize the absolutely amazing mistake this guy has made you will laugh your posterior off!
The message is that we need to know the spectrum level of reflections to be able to gauge their relative audible effects. This can be done using time-domain representations, like ETC or impulse responses, but it must be done using a method that equates the spectra in all of the spikes in the display, such as bandpass filtering. Examining the “slices” of a waterfall would also be to the point, as would performing FFTs on individual reflections isolated by time windowing of an impulse response. Such processes need to be done with care because of the trade-off between time and frequency resolution, as explained in Section 13.5. It is quite possible to generate meaningless data. All of this is especially relevant in room acoustics because acoustical materials, absorbers, and diffusers routinely modify the spectra of reflected sounds. Whenever the direct and reflected sounds have different spectra, simple broadband ETCs or impulse responses are not trustworthy indicators of audible effects". p. 93
If you need a text to explain this to you, the book won't help! It's too late! And what is scarier is the asinine conclusion that is drawn from this!
So, if we have a stimulus such as a tone at 500 Hz, the total modulation envelope of the signal may not be the same as a tome at say 5kHz.
Absolutely someone without a clue can generate wacked data! And only someone similarly clueless as to why would blame the tool!.
Combine that with the fact that existing treatments may indeed effectively EQ the incident energy and act as equalization, effecting some frequencies more than others.
Thus if one uses live material as a stimulus that may feature varying spectral content at differing times of the program, and you have boundaries or boundary treatments that do not behave in a broadband manner and may indeed effectively EQ the incident and reflected energy, you may indeed end up with whacked data.
And anyone who conducts a test in such a manner is an idiot.
Best practices require that we evaluate the behavior of the boundaries and /or treatments specifically to ascertain their behavior over the full specular spectrum.
Such boundaries that do not exhibit such a broadband response should be corrected.
And since when has it ever been best practice to play stimuli consisting of different spectra and attempting to equate them? Again, this is not a source of error, it is a MISTAKE. A MAJOR MISTAKE
. And the sign of an incompetent operator.
And apparently we need a book to tell us that measurements made via a MISTAKE are not valid!
And this is further compounded by some interpreting this as a fundamental flaw of the measurement process and not of an operator who hasn't a clue as to what they are doing?!?!?!?!?!?!?!
To quote Bill Engvall: "Here's your sign!!!"
Of course boundaries that are not broadband and which do not function in a linear fashion will effectively EQ the incident energy!
And attempting to compare unlike stimuli which by definition consist of non-equivalent energy content, is so whacked as to render the label of a “mistake” an understatement!!!
Best practices mean that we first evaluate boundaries for their behavior, and effect correction if such is the case.
And then testing ALWAYS dictates that we compare apples with apples!
And the fact that someone can construct a test focusing on the arrival time and gain of energy with respect to time and not be aware that the energy being compared must be equivalent is a fool.
But apparently a few amazed that conducting measurements improperly can result in whacked data feel the need to repeat their shocked amazement to readers who are also apparently assumed to be fools, as they all sit amazed at the OBVIOUS ramifications of such an asinine practice.
Thus, for those, unlike the intended crowd above, who have a few functioning brain cells, you have several CORRECT choices in properly using the tool!
As the tool can be used for a near limitless array of applications, (including a plethora of well designed variations) with regards to boundary investigations a simple rule of thumb implies that one:
1.)Ascertain the spectral nature of the boundaries followed by the behavior of any existing treatments. This will most probably require that one remove any treatments and first establish a baseline of performance for the boundaries.
2.)Once this is established and any lack of uniform broadband behavior rectified, insure that any treatments employed (assuming they are necessary and perform the desired function) are also broadband.
And except for the purposes of selectively ascertaining degrees of deficiency, identical broadband sweeps should generally be used for testing, with any tests intended to be directly compared conducted with equivalent stimuli under equivalent conditions. And if broadband sweeps are not employed, care MUST be exercised in comparing any results generated by dissimilar stimuli! Depending upon the nature of the behavior to be examined, sweeps maybe be bandwidth limited in a narrow fashion, realizing the reduction in resolution, or 'bandwidth limited' in the broadband, increasing the resulting resolution and generally employed..
"The message is that we need to know the spectrum level of reflections to be able to gauge their relative audible effects. This can be done using time-domain representations, like ETC or impulse responses,
but it must be done using a method that equates the spectra in all of the spikes in the display, such as bandpass filtering.".Toole
OF COURSE IT CAN! And if you know how to use the tool properly, you would be doing this anyway!
Yup, The ETC which 'can be used properly' is declared "obsolete" by someone both unable to read and who hasn't a clue as to how to use it!
The next time we have someone present a book report, is it possible to ask that they be able to properly read for meaning?
And it become obvious from Chicken Little's rant that he hasn't a clue as to how to properly use the ETC or any such similar measurements!
And before he becomes even more upset, using identical broadband sweep stimuli is satisfies the same requirement as the perceived mistaken need to use limited band=ass measurements. The effective bandpass is simply wider!.
Failure to use best practices in testing does not indicate a flaw in the measurement technique; it instead indicates that the person conducting the tests is an idiot who is not qualified to conduct such tests.
Bandwidth limited tests can indeed be used for diagnostic purposes, provided one is familiar with how to do them.
Provided that such tests are properly conducted and that the results are interpreted properly.
NEWSLASH!!!! Cars are defective!!! Congress demands recall of all vehicles after man blames car for decreased gas mileage after filling the gas tank with sand!
This has been stated on multiple times ever since a few amazed souls imagined that some would be so stupid as to conduct such flawed tests and to improperly attempt to compare apples with oranges and to think such a comparison is valid!
But it is not the limitation of the tool that there are idiots who are not qualified to use them.
And it is likewise a foolish endeavor of some who are unable to recognize such mistakes of process who then attempts to fault the tool and not the operator. And in doing they would not be much smarter than those who conduct such flawed tests. And the need to point out such an OBVIOUS MISTAKE in understanding and process where MISTAKEN PROCEDURES LEAD TO WACKED RESULTS seems like the result of someone having in fact made that very mistake and now subsequently redirecting the attention to not only others but in some braindead manner to the tool, as if the tool prevented them from thinking! As if someone stops and thinks about this, going to such trouble to illustrate that a flawed measurement practice can result in whacked data that one cannot directly compare begs the question of proper measurement technique.
And it seriously appears to be a case where someone feels the need to deflect the attention from their own mistaken use of the tool and to make it look as if only ‘others’ would fall victim to their own foolish mistake!
So, fundamentally there is NOTHING here except an example of flawed measurement process, and it is NOT the fault of the tool – except insofar as the tool does not absolutely prevent one from making a mistake! And I guess in that respect, yes, the tool is flawed in that it does NOT prevent you from being an idiot and doing things incorrectly.
Yup, doing that is a MISTAKE! And thank goodness that we have a book that you can buy that identifies one of a myriad ways that an ignorant operator cam make mistakes.
But where I come from, that is the fault of the ignorant operator, NOT of the tool.
But seeing as we live in a culture literally dominated by the “victim mentality where no one is responsible, such a warning may indeed be applicable for the intended audience off the book which are apparently assumed to not be smart enough to conduct such a test properly. Well, at least Toole has found one reader for whom the message was aptly intended! And he is still running about blaming the tool!
And when you thought things could not become more ridiculous!!!!
But stay tuned, as will be treated to a book report blaming the manufacturers of medical equipment after some fool at home operates on themselves in order "to let the heat escape" as a result of their setting a thermometer on a radiator and misinterpreting the reading to imply that their body temperature was 180 F.