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
New research suggests that when you are dead, you are dead. n=in billions over the centuries. So far, dead bodies haven’t appeared to care much about the consciousness left or not left after the fact.
If some spirits are dead absolutely after death, I might consider to adopt your limited, non scientific, curious modern materialist superstition....I dont want to encounter some spirit on a reincarnation....


 I will give you a way to figure this thing out: use your imagination, and learn that this gift is not only there to lie.... The creative imagination of man is that give us access to art, science, and numbers....Without that imagination we  are like animals.... To perceive  the invisible is a gift to scientist and artist...
geoffkait,

Will you continue posting numbers and recent news on that virus thread? It seems only mahgister and you can post there so I would like to follow your numbers.
mahgister,

If you only paid attention to what I post and not focus on trying to insult me at every moment, you would not need to repost my words a couple of weeks later and credit whoever you are infatuated with at that moment.

When you are dead, you are dead. That is how it goes. Believe in what you wish.
geoffkait,

Also, from that other thread, are you interested in booties or in shoe covers? Booties are much less practical and harder to come by.
If you only paid attention to what I post and not focus on trying to insult me
You dont even remember anything correctly.... I even apologize few times to you to keep peace to no avail... You go on harassing my posts with half truth to your convenience....


And after that glupson you ,make threat in my back, I can give you the posts if you want, and you accuse me of something inacceptable like contribute to kills people.... This is too much.....

I am a soul who can apologize, I can recognise when I am wrong, I never made any threat here to anyone, I am friendly with people of different political opinions....but there is limit.... You crossed them...


Dont read my posts and dont trail me anymore....