Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

BEGINNER!!  Need help understanding Crossover/Impedance/Wattage
BEGINNER!!  Need help understanding Crossover/Impedance/Wattage
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 9th December 2019, 11:44 AM   #61
Allan M is offline Allan M
diyAudio Member
 
Join Date: Nov 2019
Quote:
Originally Posted by Gnobuddy View Post
The advertising always claimed to deliver something along the lines of "The sounds of one hundred glorious vintage guitar amplifiers in one tiny box!", while early Line 6 products delivered a reality closer to "The sounds of one hundred kazoos in one tiny box!"
Early 80s keyboard synthesizers spring to mind. Listening to them now they sometimes remind me of Atari console games of the same era.

Quote:
Exactly! IMO this is quite typical of what happens when art meets technology: creative artists push the technology past the limits envisioned by the engineer, until the technology breaks, and then the artist creates her most expressive art using the freshly exposed flaws in the technology.

I expect the "engineer" who invented the first paint-brush intended it to produce a smooth, uniform streak of colour. But artists quickly found flaws in the technology - make the paint too dry, and you get streaky and non-uniform marks on the canvas; make it too wet, you create a wash of non-uniform colour; change the type of solvent or the amount of pigment, and you end up with visible brush strokes instead of a smooth wash. And very soon all of these flaws in paintbrush technology became parts of any good painter's repertoire of techniques.
That parallel occurred to me also. In fact, good painting does exploit the quality of the materials being used, in a balance between a "transparent window" onto a realistic scene (photo-realism) and obvious brush-strokes - integrating the image of the subject and the qualities of medium (the marks of the implement and the medium) into a coherent whole. These are always the most exciting paintings or drawings.

On the guitar amp front, Leonidas Fender knew just enough about electronics to pick up a soldering iron and copy standard Hi-Fi valve circuits out of the back of RCA valve catalogues to create his early guitar amplifiers. The music he favoured - country and surf - was all based around the clean, bright, undistorted sound of the guitar, and that's what he intended his amplifiers to produce. They were based on standard Hi-Fi circuitry of the time, minimally altered to accept guitar signals; Merlin Blencowe (aka "The Valve Wizard") refers to them as "Adequate-Fi", as good a description as any![/quote]

I believe valve amplifier technology did eventually progress to the point of genuine hi-fi, except perhaps for the lower bass range, which was limited by practical output transformer core size. However, transistors surpassed valves in terms of linearity and output power, though only by allowing massive amounts of negative feedback and perhaps better impedance matching between amplifier output and loudspeaker. Also, they can do it for a lower price, with smaller size, less weight and lower power consumption (no cathode heating).

Quote:
The ones I used to buy in the USA in the 1990s all went out of business, one by one.
Electronics Australia (which began as Wireless Weekly in 1922) finished in 2000 but Silicon Chip, which was started in 1987 by an Electronics Australia editor, took it's place in the market, as microprocessors took over the field. SC still sells and has moved with the times. New magazines for young hobbyists are centered around Raspberry Pi and Arduino digital technology.

Quote:
Many years later, "Make" magazine arrived, and kick-started a renaissance in the oh-so-shocking idea that you could actually make things yourself, rather than buying everything from a shop. "Make" has found a niche audience and still exists today.

While I'm grateful for its existence, I doubt it has captured the attention of more than a tiny fraction of today's youth.
In Australia, coding has become a big thing among youth. The government is pushing it as part of school education, in preparation for the coming AI and IOT revolution. The magazines I mentioned integrate coding with electronics, as well as DIY construction and mechanical design, whereas up to the 2000s hobby electronics was more about straight circuit building.

Quote:
There was a survey a couple of years ago that found the median age of diyAudio members was 55. I bet that number is steadily increasing, too.
I guess today's "geek" tends to think there's an app they can download for anything they want to do.
  Reply With Quote
Old 9th December 2019, 04:27 PM   #62
Allan M is offline Allan M
diyAudio Member
 
Join Date: Nov 2019
Quote:
Originally Posted by Gnobuddy View Post
The original Mackie HR824 monitors were rated at +/- 1.5 dB from 39 Hz - 20 kHz, a pretty amazing accomplishment, and IIRC we measured it as flatter than that through the crucial mid frequencies.

This measurement required a mic that was much flatter yet; fortunately my then-employer had one, a Bruel & Kjaer measurement mic and accompanying preamp, which was ruler-flat from 4 Hz to 100 kHz (!!!), and which I was told cost several thousand dollars at the time.

Each HR824 speaker had built in electronic EQ which was individually tweaked at the factory to compensate for inevitable manufacturing tolerances in drivers and enclosures, and that's how Mackie managed to achieve such a flat response.

The poor-mans alternative at the time was the Alesis M1 Active near-field monitors, which were equally flat, except for the bottom octave. They didn't reach down as far as the Mackies, and a poorly thought out decision to push bass response as low as possible, and then roll it off abruptly, resulted in boomy and poorly controlled deep bass. Other than that, though, they were very good speakers.

...

So I bought a set of near-field studio monitors that were great bang-for-the-buck, combined them with a subwoofer to flesh out the frequencies below 70 Hz or so, and have been content with them for some 15 years or more now. They're definitely not perfect, but they're pretty good.
Would this current-model Mackie monitor (MK-HR824 MK2) perform as well as the original HR824?

8" 2-way High Resolution Studio Mon | Mackie - Amber Tech

There are other, cheaper models in the same range:

% Search Results - Amber Tech
  Reply With Quote
Old 9th December 2019, 11:49 PM   #63
Gnobuddy is offline Gnobuddy  Canada
diyAudio Member
 
Join Date: Mar 2016
Quote:
Originally Posted by Allan M View Post
...In fact, good painting does exploit the quality of the materials being used...
My wife is a painter (with a college degree in fine art), and I've learned a lot from watching her work over the years.
Quote:
Originally Posted by Allan M View Post
I believe valve amplifier technology did eventually progress to the point of genuine hi-fi
Sure, but Leo began selling guitar amps in 1945, and these started as copies of inexpensive back-of-the-catalogue amplifier designs intended for use in affordable radios and record players. Nothing like the price-no-object Williamson amps that were still a few years away.
Quote:
Originally Posted by Allan M View Post
However, transistors surpassed valves in terms of linearity...only by allowing massive amounts of negative feedback
Interesting fact: inside a triode valve, the electric field between cathode and grid overlaps the electric field between cathode and anode. As a result, there is heavy negative feedback built right into the fundamental nature of the triode, which is what makes it a fairly linear (and low voltage gain) device!

And what happens if you remove this invisible internal negative feedback between anode to cathode? You can do this by inserting a grounded (mesh) electrode between control grid and anode. We all know what happens if you do this: you get a tetrode - which has more voltage gain, and far more nonlinearity.

In fact, a tetrode has so many linearity problems that the pentode was quickly invented. It too has much higher nonlinearity, and much higher voltage gain, than the triode with its built-in negative feedback.

Unsurprisingly, transistors are also extremely nonlinear, like valves, unless you allow negative feedback from output to input. The difference is that triodes have that feedback already built into the physics of the device; BJTs and JFETs don't.
Quote:
Originally Posted by Allan M View Post
Also, they can do it for a lower price, with smaller size, less weight and lower power consumption (no cathode heating).
Indeed! Not to mention much lower thermal noise, because the device operates at about one-quarter of the absolute temperature (i.e. temperature in Kelvin) of a heated valve cathode, and thermal noise is proportional to the square root of the absolute temperature.
Quote:
Originally Posted by Allan M View Post
New magazines for young hobbyists are centered around Raspberry Pi and Arduino digital technology.
Funny thing: just about every time I look up a Raspberry Pi or Arduino project, it's been created by an adult, usually an adult male with a techie background, who has enough disposable income to buy these toys, and enough technical knowledge to use them effectively.

Very often the buyer is an actual software / hardware / firmware engineer, who's grown tired of writing reams of boiler-plate C++ code just to set PIC configuration fuses and PWM timing in his Microchip PIC-based project; so he shells out the bucks for an Arduino or Rpi, and is happy as a clam playing with it instead. More fun, less tedious boiler-plate code.

I own a couple of Raspberry Pi 3's, and a couple of Arduinos. And I'm no exception to the rules: adult male, check; technical education, check; have written software for a living, check; don't want to bother with set-up code for Microchip PICs, check.

I would love to know what percentage of Rpis and Arduinos area actually in the hands of children. I haven't been able to find any trustworthy numbers on this, but I would hazard the guess that it's less than 10% of sales. Maybe much less.
Quote:
Originally Posted by Allan M View Post
In Australia, coding has become a big thing among youth. The government is pushing it as part of school education, in preparation for the coming AI and IOT revolution.
Both my wife and I have been involved with education for a long time. In the US, there was/is enormous pressure from the govenment to teach students what they call "STEM", management-speak for "Science / Technology / Engineering / Mathematics".

Look behind the scenes, however, and you find the STEM initiative didn't come from anybody in education or education research; it didn't come from educators or those who study education and educational needs. Instead, it came from powerful lobbies run by companies like Microsoft, who want access to an army of cheap labour to write still more insecure code for their next generation of crappy operating systems.

When I surveyed the job market for college graduates with STEM degrees, what I found was very few jobs for science graduates (when the cold war ended, so did most research labs; at college level, even permanent teaching jobs have disappeared, replaced by short term hire-and-fire "adjunct" teaching jobs.)

Mathematics is even worse; at college level, virtually the only jobs for maths graduates are in teaching, and they are the same short-term adjunct posts. We have many young people with PhDs in science and math living at the edge of poverty now. Here's one shocking glimpse at how bad things are: Facing poverty, academics turn to sex work and sleeping in cars | US news | The Guardian

How about the "TE" bits, technology and engineering? Here's an interesting reality check from a few years ago: Canadian Engineers: The Crisis of Under-Employment after Graduation

So the government is pushing STEM down the reluctant throats of hundreds of thousands of North American students with no interest in those fields, and who will have no job prospects if they actually take up serious study in those areas. Brilliant.

Meantime, most of the world's actual coding and engineering appears to have moved to China, India, the Philipines, and other similar countries, where the general population has no cultural fear of mathematics, and American companies like Microsoft can hire programmers for a fraction of the wages they would have to pay North American employees.

There is another factor which nobody is talking about: anyone can learn to write low-quality boilerplate code, but only a tiny, tiny fraction of people ever become great programmers, or learn to love the task of programming.

Writing code for a living is a very peculiar life, with long hours spent in isolation in front of a screen, away from almost everything that makes life actually worth living to most people: you're away from friends, loved ones, fresh air, sunlight, nature, sports, socialization, physical exercise.

Code for ten years, and you will likely be a lonely, overweight, unhealthy,isolated, unbalanced human being; great coders typically start out as unbalanced human beings, people who understand the idiotically logical rules of coding better than the complex interactions between human beings, people who are very often somewhere on the autism spectrum.

This is not the way most people's brains are wired. I don't see that changing, just because fifty thousand children learned how to make an LED connected to an Arduino blink on and off by writing five or six lines of code.

I spent a lot of hours coding in my twenties, and even made my living at it for a couple of years. And you know what? I'm never getting back all those lonely hours I spent poking at a keyboard, hunched over in front of a monitor.

I still write code for small personal projects like the automated Arduino-based cat feeder I built this year, or for friends, like the teacher who wanted a way to randomly pair up his students for their lab work; I wrote him a simple HTML/Javascript program to do the job.

But now I'm aware that every hour spent coding is an hour away from my wife, my cat, my guitars, from sunshine, fresh air, the beauty of the outdoors, exercise, laughter - all things that add much more to the quality of my life than completing another coding project.

Expressing that thought in C/C++:
Code:
//Function to check on current quality of life
//"increment" must be between 0 and 0.25
//error checking for value of "increment" not shown for clarity


 float quality_check( increment ){
    float baseline = 0.75; //baseline happiness %
    float quality_of_life;
    int coding;

    srand(time(NULL)); // generate random seed
    coding = rand()%2; //randomly generate either 0 or 1


//check if you're coding, assign appropriate quality_of_life 

    if(!coding){
        quality_of_life = baseline + increment;
    }else{
         quality_of_life = baseline - increment;

         if (quality_of_life < 0){
            quality_of_life = 0;
         }
    }
    return quality_of_life;    
}


-Gnobuddy
  Reply With Quote
Old 9th December 2019, 11:57 PM   #64
Gnobuddy is offline Gnobuddy  Canada
diyAudio Member
 
Join Date: Mar 2016
Quote:
Originally Posted by Allan M View Post
Would this current-model Mackie monitor (MK-HR824 MK2) perform as well as the original HR824?

8" 2-way High Resolution Studio Mon | Mackie - Amber Tech

There are other, cheaper models in the same range:

% Search Results - Amber Tech
I wish I knew...I no longer have any contacts in the pro-audio world, and therefore have no insider information to share.

Search to see if Mackie has provided a factory anechoic-chamber frequency response curve for their current version of the HR-824, or if there are any independent third-party reviews that include one. (These are rare, as most reviews are written by technically illiterate self-proclaimed "golden ears".)

Ideally you would also find polar frequency plots taken at several off-axis angles, to give you an idea how good treble dispersion is (or isn't).

The original HR-824 used a shallow "horn" around the tweeter to narrow its treble dispersion a little at the crossover frequency, which made for a smoother transition from woofer to tweeter.

(In most 2-way speakers, the much bigger woofer "beams" at the crossover frequency, while the much smaller tweeter disperses sound widely, so there is an abrupt change in sound dispersion as frequencies move through the crossover region. This can spoil stereo imaging and create a subtle sense of something unnatural or "not quite right" about the soundfield.)


-Gnobuddy
  Reply With Quote
Old 10th December 2019, 11:24 AM   #65
Allan M is offline Allan M
diyAudio Member
 
Join Date: Nov 2019
Quote:
Originally Posted by Gnobuddy View Post
Sure, but Leo began selling guitar amps in 1945, and these started as copies of inexpensive back-of-the-catalogue amplifier designs intended for use in affordable radios and record players. Nothing like the price-no-object Williamson amps that were still a few years away.
It got better than the Williamson amplifier. The ultralinear configuration allowed great improvements on previous designs.

Quote:
Interesting fact: inside a triode valve, the electric field between cathode and grid overlaps the electric field between cathode and anode. As a result, there is heavy negative feedback built right into the fundamental nature of the triode, which is what makes it a fairly linear (and low voltage gain) device!

And what happens if you remove this invisible internal negative feedback between anode to cathode? You can do this by inserting a grounded (mesh) electrode between control grid and anode. We all know what happens if you do this: you get a tetrode - which has more voltage gain, and far more nonlinearity.

In fact, a tetrode has so many linearity problems that the pentode was quickly invented. It too has much higher nonlinearity, and much higher voltage gain, than the triode with its built-in negative feedback.
The ultralinear circuit allowed pentodes and tetrodes to assume the characteristics of triodes.

Quote:
Funny thing: just about every time I look up a Raspberry Pi or Arduino project, it's been created by an adult, usually an adult male with a techie background, who has enough disposable income to buy these toys, and enough technical knowledge to use them effectively.
Yes, I gathered that they are suitable for more than just kid's games and projects. In fact, these "kids" projects make use of circuits based around common, industry standard ICs as well,

Quote:
Look behind the scenes, however, and you find the STEM initiative didn't come from anybody in education or education research; it didn't come from educators or those who study education and educational needs. Instead, it came from powerful lobbies run by companies like Microsoft, who want access to an army of cheap labour to write still more insecure code for their next generation of crappy operating systems.
I have the suspicion that school education in general is now being oriented toward turning out cogs in the technocratic hive society. We are fulfilling Lenin's dream, which he based on the production philosophy of Henry Ford. Huxley had a lot of insight.

Quote:
When I surveyed the job market for college graduates with STEM degrees, what I found was very few jobs for science graduates (when the cold war ended, so did most research labs; at college level, even permanent teaching jobs have disappeared, replaced by short term hire-and-fire "adjunct" teaching jobs.)
That's a little surprising, given the explosion of technology since the end of the cold war. That was the beginning of the information age. Many commentators say that this will result in another "cold war" in cyber-security.

Quote:
Here's one shocking glimpse at how bad things are: Facing poverty, academics turn to sex work and sleeping in cars | US news | The Guardian
There has long been a disproportionate number of high-school graduates entering university to "increase their career prospects" who are not actually interested in having any particular career. It seems they want to avoid being lifelong wage slaves. However, most who do get graduate jobs end up being moderately higher-paid administrative hacks.

Quote:
So the government is pushing STEM down the reluctant throats of hundreds of thousands of North American students with no interest in those fields, and who will have no job prospects if they actually take up serious study in those areas. Brilliant.
There is another factor which nobody is talking about: anyone can learn to write low-quality boilerplate code, but only a tiny, tiny fraction of people ever become great programmers, or learn to love the task of programming.
The emphasis on coding in school education is to some extent merely to prepare students for the increasing digitalisation of society, which is bound to require a degree of technical skill or knowledge for people of all vocations even outside of the IT field. Coding may become as important as literacy in reading and writing.

Quote:
Writing code for a living is a very peculiar life, with long hours spent in isolation in front of a screen, away from almost everything that makes life actually worth living to most people: you're away from friends, loved ones, fresh air, sunlight, nature, sports, socialization, physical exercise.

Code for ten years, and you will likely be a lonely, overweight, unhealthy,isolated, unbalanced human being; great coders typically start out as unbalanced human beings, people who understand the idiotically logical rules of coding better than the complex interactions between human beings, people who are very often somewhere on the autism spectrum.
Most of us wouldn't do it for any money.There have been many "computer nerds" who get endless thrills from coding for hours every day but this probably does not translate very well for everyone into the workplace.

Quote:
This is not the way most people's brains are wired. I don't see that changing, just because fifty thousand children learned how to make an LED connected to an Arduino blink on and off by writing five or six lines of code.
These projects are not purely coding though. There is circuit design and mechanical construction, including 3-D printing. It's something of a craze and some kids are surprisingly advanced. It's really just the modern version of the age-old electronics or mechanical hobbyist, with digital technology added. It's something young boys have always done. Now, girls are being drawn into it, though I wonder how long that will last. Most adult women I know are still into shopping and wouldn't go two meters from a Raspberry Pi kit.

Quote:
Expressing that thought in C/C++:
Code:
//Function to check on current quality of life
//"increment" must be between 0 and 0.25
//error checking for value of "increment" not shown for clarity


 float quality_check( increment ){
    float baseline = 0.75; //baseline happiness %
    float quality_of_life;
    int coding;

    srand(time(NULL)); // generate random seed
    coding = rand()%2; //randomly generate either 0 or 1


//check if you're coding, assign appropriate quality_of_life 

    if(!coding){
        quality_of_life = baseline + increment;
    }else{
         quality_of_life = baseline - increment;

         if (quality_of_life < 0){
            quality_of_life = 0;
         }
    }
    return quality_of_life;    
}
You should submit that one for publication, with an LED circuit added to it.
  Reply With Quote
Old 12th December 2019, 09:49 PM   #66
Gnobuddy is offline Gnobuddy  Canada
diyAudio Member
 
Join Date: Mar 2016
Quote:
Originally Posted by Allan M View Post
...The ultralinear configuration...
Also known as negative feedback.

That's the funny part, all the best valve (Hi-Fi) amps used as much negative feedback, local and global, as they could possibly manage to get away with. At the time, the loudest voices were from engineers, and they understood that more negative feedback is always a good thing, as long as there is an adequate stability margin and slew rate, and input signals are properly band-limited if necessary.

That was before the idiotic "negative feedback is bad, and more is worse" superstition became widespread.
Quote:
Originally Posted by Allan M View Post
The ultralinear circuit allowed pentodes and tetrodes to assume the characteristics of triodes.
Yes. In a pentode or beam tetrode, the screen grid takes away the built-in negative feedback of the triode, by electrically isolating the cathode-anode electric field from the cathode-control grid field.

"Ultralinear" feedback from anode to screen grid essentially put back what the screen grid took out!
Quote:
Originally Posted by Allan M View Post
Yes, I gathered that they are suitable for more than just kid's games and projects.
Of course (the Arduino is based around an industry-standard series of Microchip PICs, the Rasberry Pi uses a cellphone chipset).
Quote:
Originally Posted by Allan M View Post
...school education in general is now being oriented toward turning out cogs in the technocratic hive society.
Agree. In the past several decades, governments have stopped thinking of education as, well, education, and have started to think of it purely as work-skills training. For many in government, the goal isn't to open the minds of young people, but to turn them into the next generation of mindless worker bees.

Fortunately, most teachers I know are still striving to educate and inform and teach critical thinking, and to open their pupils minds, though that is no longer their official mandate.
Quote:
Originally Posted by Allan M View Post
...based on the production philosophy of Henry Ford. Huxley had a lot of insight.
Henry Ford was a Nazi sympathizer and a hate-filled antisemitic. ( Ford's Anti-Semitism | American Experience | Official Site | PBS ). What a man to emulate.

Huxley changed my world when I first read "Brave New World". I have seen many ideas from the book turn into reality in subsequent decades, including today's omnipresent and all-encompassing surveillance of the masses via smartphones.
Quote:
Originally Posted by Allan M View Post
The emphasis on coding in school education is to some extent merely to prepare students for the increasing digitalisation of society, which is bound to require a degree of technical skill or knowledge for people of all vocations even outside of the IT field.
What I'm actually seeing is a steady decline in the level of technical skill needed to function in these fields. When I first encountered computers, mainframes and early IBM PCs running DOS, we only had text interfaces, and you had to learn dozens of machine-specific operating system commands to do even the simplest task, such as word-processing. You also had to understand concepts such as a directory tree.

Douglas Englebart and his crew had already figured out how to simplify things and make computers usable by children with their little childish brains ( Douglas Engelbart - Wikipedia ).

Then Apple came along, took Englebart's work, and sold it to adults rather than children. Adults no longer needed to know very much to use a computer; Apple's claim was "Click on the button, and the computer will guess what you intended and do it for you."

Even that required the ability to use a mouse. When the touch-screen smartphone arrived a couple of decades later, that last little skill was no longer necessary. All you need is the ability to swipe with your thumbs.
Quote:
Originally Posted by Allan M View Post
Coding may become as important as literacy in reading and writing.
It already was in the 1990s, when I was in college - particularly if you were studying science or engineering.

Back then, as one tiny example, I coded my own birthday reminder tool in C on a SPARC workstation running Unix. It would send me daily reminder emails for upcoming family birthdays starting three weeks ahead of time, because it took two weeks for a birthday card to get home via airmail. I wrote it for the most typical reason: I had need for it, and it didn't exist, so I created it. (One of my officemates immediately borrowed a copy and used it for himself.)

Three decades later, there is LESS need for students in those same areas to code, not more. How many calendar apps can you find today?

Now there's already an app for almost everything you might need to do...just download it, swipe you thumb over it, done. No need to use your brain.
Quote:
Originally Posted by Allan M View Post
Most of us wouldn't do it for any money.
Exactly! It is not the life most people want.
Quote:
Originally Posted by Allan M View Post
These projects are not purely coding though. There is circuit design and mechanical construction, including 3-D printing.
It's nice to see some of those old lost skills coming back in new guises. Many kids did electronics in the 1960s and even earlier, and many more had shop skills that let them build mechanical things using their dad's tools. Back then, kids as young as seven or eight years old routinely built delicate, complex balsa-wood model aircraft powered by twisted rubber-bands, and flew them.

I recently re-read Mark Twain's "The Adventures of Huckleberry Finn", and it is eye-opening to find out the number and extent of skills that ordinary, uneducated young boys were expected to possess in 1883, when the book was written.

I myself built my first electronic circuit - a crystal radio with coils I wound myself and an OA79 diode I got from my big brother - at age 7 or 8, I can't recall. I know I was "designing" and building simple transistor circuits, with a soldering iron, at age 9; my "design" abilities at that time consisted of trying multiple resistor values until the PNP germanium transistor common-emitter stage actually amplified the audio signal. I didn't yet know any of the mathematics I would need to do better than that.

But even then I knew what pulse width modulation was, and so understood how the "morse code tester" built by a local radio ham worked; you tapped in a stream of dots or dashes, and the tester indicated on a meter if you were achieving the proper durations (dot = 1 unit of time; dash = 3 units of time; gap between dots or dashes = 1 unit of time.)
Quote:
Originally Posted by Allan M View Post
Most adult women I know are still into shopping and wouldn't go two meters from a Raspberry Pi kit.
I've known quite a few women who were excellent computer programmers when they needed to be. However, they usually preferred spending time with people, pets, animals, or nature to being stuck in a windowless fluorescent-lit room staring for hours at a computer monitor, trying to track down the show-stopper bug in the code you'd been trying to get working for the past ten hours.

They knew that your friend, cat, dog, or boyfriend loves you back; the computer doesn't. Ultimately, it's less satisfying to spend time with the computer.

Being male and less in touch with my emotions, it took me a lot longer to figure out what those women knew immediately. It was only when I was older, and had fallen thoroughly in love with the woman who is now my wife, and had begun to remember all the things I had given up to find time to program, that I too began to realize there were more rewarding ways to spend my all too brief hours on this planet.
Quote:
Originally Posted by Allan M View Post
You should submit that one for publication, with an LED circuit added to it.
Nah, it would be considered subversive by the powers that be.

What they want is a program like this one:
Code:
    #include <iostream>
    using namespace std;
    int main() 
    {
          while(1){
               cout << "Coding will make you rich, famous, and beloved by all!";
          }
          return 0;
    }
-Gnobuddy
  Reply With Quote
Old Yesterday, 11:06 AM   #67
Allan M is offline Allan M
diyAudio Member
 
Join Date: Nov 2019
Quote:
Originally Posted by Gnobuddy View Post
Also known as negative feedback.

...

That was before the idiotic "negative feedback is bad, and more is worse" superstition became widespread.

...

"Ultralinear" feedback from anode to screen grid essentially put back what the screen grid took out!
I think the objection to NFB in transistor circuits is that, aside from being very high, it is around the entire amplifier, rather than just single stages of the amplifier, thus having a greater affect on it's overall response.

Quote:
Fortunately, most teachers I know are still striving to educate and inform and teach critical thinking, and to open their pupils minds, though that is no longer their official mandate.
Teachers themselves are being trained not to do just that. I get the impression that they are also being taught, along with that, a different definition of "open mind".

Quote:
Henry Ford was a Nazi sympathizer and a hate-filled antisemitic. ( Ford's Anti-Semitism | American Experience | Official Site | PBS ). What a man to emulate.
Yes, he was But like many large corporations and smaller entrepreneurs of his time, he also built factories in the Soviet Union to build the Soviet military industrial complex. That's the great thing about totalitarian regimes. They are so easy to do business with. You only have to talk to one man.

Quote:
Huxley changed my world when I first read "Brave New World". I have seen many ideas from the book turn into reality in subsequent decades, including today's omnipresent and all-encompassing surveillance of the masses via smartphones.
He had some good insights. I read in a chapter of Philopp Blom's book "Fracture: Life and Culture in the West, 1918-1938" 9(2015) that Lenin assigned a comrade who had worked in a Renault factory in France while in exile before the revolution to oversee his plan for re-making Soviet society.

While at Renault, this comrade (who's name I can't remember) had learned Henry Ford's philosophy of maximum production efficiency. This philosophy had actually been conceived by Frederick Winslow Taylor in the 19th C, and was known as Taylorism.

Lenin took this philosophy of factory production and applied it to society as a whole. Every single detail of Soviet society, no matter how small, was to be tuned for maximum efficiency of production and living. Lenin even planned to replace people's names with serial numbers. Lenin's slogan during this time was "Americanisation". (Apprently, efficiency demanded that the man who introduced Lenin to this concept later be seized by Cheka agents and shot.)

In fact, even the application of Taylorism to society was not entirely Lenin's, since large companies in the U.S. had long been building "company towns" for employees of their large plants to live in. Lenin and Stalin modeled Soviet society on the company town. Taylor's philosophy is also called "scientific management." A socialist society is a managerial society. Marx called his form of socialism "scientific socialism".

Therefore it impresses me that back in 1930, when few people would see any connection between socialism and capitalism, Huxley foresaw a society which had elements of both socialism and monopoly capitalism. Not free-market capitalism, where the state stays out of business and business stays out of the state, and trade is based on competition, but state capitalism or monopoly capitalism, where everyone works for one man and everyone buys from one man.

Quote:
What I'm actually seeing is a steady decline in the level of technical skill needed to function in these fields. ...
Good point. It was inevitable that computers would be made convenient to use and require less skill or training.

Quote:
When the touch-screen smartphone arrived a couple of decades later, that last little skill was no longer necessary. All you need is the ability to swipe with your thumbs.
Ironically, not being raised with "swipe" devices, I actually find them insanely complicated to use. I am used to systems based on straight, tree-structured menus and directories, with buttons with English labels on them which do what the label says that they do when you click on them.

Quote:
Three decades later, there is LESS need for students in those same areas to code, not more. How many calendar apps can you find today?

Now there's already an app for almost everything you might need to do...just download it, swipe you thumb over it, done. No need to use your brain.
Also true. I was surprised to meet a university IT student who said he preferred high-level to low-level programming. I thought to myself, where is the excitement in that? It's basically just stringing modules or apps together into one program.

Quote:
Nah, it would be considered subversive by the powers that be.

What they want is a program like this one:
Code:
    #include <iostream>
    using namespace std;
    int main() 
    {
          while(1){
               cout << "Coding will make you rich, famous, and beloved by all!";
          }
          return 0;
    }
The catch is that this outcome would require such total dedication that one would probably never have time to enjoy it.
  Reply With Quote

Reply


BEGINNER!!  Need help understanding Crossover/Impedance/WattageHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Help understanding driver impedance, amp power, spl bvan Car Audio 5 30th April 2015 09:49 AM
Understanding - and exploiting the impedance curve? n8skow Subwoofers 52 8th November 2014 05:56 PM
understanding Impedance graph. Aucosticraft Subwoofers 42 16th April 2013 08:43 PM
impedance and wattage rating.... jimbob212005 Multi-Way 18 10th March 2009 04:49 PM
Need help understanding transformer impedance ratios and impedance matching percy Tubes / Valves 5 28th February 2005 09:35 PM


New To Site? Need Help?

All times are GMT. The time now is 07:48 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki