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
Your ignorance at being able to see and understand the future does not change what will happen.
You think that you understand the future better than him? :)


 Ok I apologize for the disruption but sometimes it is difficult to resist to answer.... My best to all....
Can anyone name one GP doctor that got replaced by AI?  I would love to have a job that I can say anything but don't have to back up with any evidences.

Anyway, this morning I called my health insurance help center, and I was greeted with what was an AI automated helper.  I got so frustrated I almost slammed my phone.  Luckily, I was later got hooked up to a real person.  
"...the last time I checked, the US economy unemployment rate was at 3.5%."
It was a long time ago.


March was 4.4%. Newest one I do not know, but It is probably a bit higher.

https://www.washingtonpost.com/business/2020/04/16/unemployment-claims-coronavirus/

That was because of the virus. The unemployment was at around 3.5-3.6% for the good part of last year, before the virus.
2019 Unemployment by Month
  • January: The unemployment rate rose to 4.0%
  • February and March: The rate fell to 3.8%
  • April and May: The rate fell to 3.6%.
  • June, July, August: The rate rose to 3.7%
  • September: The rate fell to 3.5%
  • October: It rose to 3.6%
  • November and December: It returned to 3.5%
2020 Unemployment by Month
  • January: The unemployment rate rose to 3.6%
  • February: The rate fell to 3.5%
  • March: The rate rose to 4.4%

"Can anyone name one GP doctor that got replaced by AI?"
I think he is talking about the future, not about what has already happened.

For whatever it is worth, pharmacies have already snatched some of the work from general practitioners. You could go to your local CVS and get immunizations and be treated for some minor illnesses. Immunizations are done by pharmacists, as far as I can understand. The rest are probably nurse practitioners, but I cannot back it up with written proof.

If you want a job that is still secure for probably one generation or maybe more, become a nurse. You will have many suitors in the western world. However, real nursing is not an easy job. Becoming a nurse and then switching to administration is a different story.