IM Distortion, Speakers and the Death of Science


One topic that often comes up is perception vs. measurements.

"If you can't measure it with common, existing measurements it isn't real."

This idea is and always will be flawed. Mind you, maybe what you perceive is not worth $1, but this is not how science works. I'm reminded of how many doctors and scientists fought against modernizing polio interventions, and how only recently did the treatment for stomach ulcers change radically due to the curiosity of a pair of forensic scientists.

Perception precedes measurement.  In between perception and measurement is (always) transference to visual data.  Lets take an example.

You are working on phone technology shortly after Bell invents the telephone. You hear one type of transducer sounds better than another.  Why is that?  Well, you have to figure out some way to see it (literally), via a scope, a charting pen, something that tells you in an objective way why they are different, that allows you to set a standard or goal and move towards it.

This person probably did not set out to measure all possible things. Maybe the first thing they decide to measure is distortion, or perhaps frequency response. After visualizing the raw data the scientist then has to decide what the units are, and how to express differences. Lets say it is distortion. In theory, there could have been a lot of different ways to measure distortion.  Such as Vrms - Vrms (expected) /Hz. Depending on the engineer's need at the time, that might have been a perfectly valid way to measure the output.

But here's the issue. This may work for this engineer solving this time, and we may even add it to the cannon of common measurements, but we are by no means done.

So, when exactly are we done?? At 1? 2? 5?  30?  The answer is we are not.  There are several common measurements for speakers for instance which I believe should be done more by reviewers:

- Compression
- Intermodulation ( IM ) Distortion
- Distortion

and yet, we do not. IM distortion is kind of interesting because I had heard about it before from M&K's literature, but it reappeared for me in the blog of Roger Russel ( http://www.roger-russell.com ) formerly from McIntosh. I can't find the blog post, but apparently they used IM distortion measurements to compare the audibility of woofer changes quite successfully.

Here's a great example of a new measurement being used and attributed to a sonic characteristic. Imagine the before and after.  Before using IM, maybe only distortion would have been used. They were of course measuring impedance and frequency response, and simple harmonic distortion, but Roger and his partner could hear something different not expressed in these measurements, so, they invent the use of it here. That invention is, in my mind, actual audio science.

The opposite of science would have been to say "frequency, impedance, and distortion" are the 3 characteristics which are audible, forever. Nelson pass working with the distortion profile, comparing the audible results and saying "this is an important feature" is also science. He's throwing out the normal distortion ratings and creating a whole new set of target behavior based on his experiments.  Given the market acceptance of his very expensive products I'd say he's been damn good at this.

What is my point to all of this?  Measurements in the consumer literature have become complacent. We've become far too willing to accept the limits of measurements from the 1980's and fail to develop new standard ways of testing. As a result of this we have devolved into camps who say that 1980's measures are all we need, those who eschew measurements and very little being done to show us new ways of looking at complex behaviors. Some areas where I believe measurements should be improved:

  • The effects of vibration on ss equipment
  • Capacitor technology
  • Interaction of linear amps with cables and speaker impedance.

We have become far too happy with this stale condition, and, for the consumers, science is dead.
erik_squires
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Neurons are machines
Neurons are living systems like other cells or animals or being like me....

I own a part of me that act like a machine.... When I play tennis I am a kind of machine....When I drive a car... Etc

In this sense neuron like me are also machine... But it is not what you are saying..... This is the difference between your reductive perspective and mine...Neuron like any other living system can act like a machine but are not machines...



Schrodinger does not describe life negatively, he describe his apparent manifestation, and said all that is not mechanical, then dont reduce to the second principle....The fact that living system use his environment to dissipate his entropy in a continuous way does not reduce life to the second principle and this is what you said...
The latest hypothesis / theories is that life may actually be a predictable outcome of the the 2nd law of thermodynamics

The fact that life use his environment to adjust itself and dissipate his entropy in an improved continuous way does not justify your affirmation that life is only a predictable outcome of the second principle at all….This new hypothesis of Jeremy England is only a more interesting way to characterise systems that are more complex than the Prigogyne far from equilibrium systems and dissipative structures and complete it... That’s all....



Laws dont exist eternally, they are temporary manifestation at a certain level of the universe of the relative human understanding....

Prime numbers exist tough in an absolute sense...

My Dad can beat up your Dad!!! 
Nuh huh... my dad can beat up your Dad...


nuh huh..., 

(ibid)
My Dad can beat up your Dad!!!
Thanks on a certain level a good briefing of the situation.... :)
I am stubborn like him but I try not to depreciate others....I try.... Perhaps I was not so successful here.... :)

 By the way I am a Chet Baker fan.... My best to you....