They just move the pens around (and raise and lower them), for drawings. Some had a bank of various color pens.
The newer versions of these are large format ink jet printers. Some did tinker with them to adapt for other purposes.
Maybe you would like to read the article I wrote some years back, detailing
drivers that did benefit.
I am not knocking current source drive as such. Probably I am the only one
here to have released two commercially successful current source amplifier
products.
A very good paper:
Swen Müller, Transfer Function Measurement with sweeps. Reviewed and compared are methods of measurement including TDS, MLS, Dual channel FFT, stepped sine, impulses, periodic sequences of length 2^n, and non periodic sweeps.
http://www.mariobon.com/Articoli_storici/Comparison_sweep_Measure_OK.pdf
Swen Müller, Transfer Function Measurement with sweeps. Reviewed and compared are methods of measurement including TDS, MLS, Dual channel FFT, stepped sine, impulses, periodic sequences of length 2^n, and non periodic sweeps.
http://www.mariobon.com/Articoli_storici/Comparison_sweep_Measure_OK.pdf
John, on a brief look alone (I'll read it through later). isn't Mr Heyser saying something pretty similar to what you, I, Frank and a few others have been saying all along and for what we got blasted by the objectivist fedayeens, namely that you CANNOT measure everything?
The gall of the man!
The gall of the man!
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So,could-you share with us your conclusions ( or feelings) about the subjective benefit of this technology ?
Are-yous speakers curent driven in your prefered home personnal system ?
The gall of me alsoJohn, on a brief look alone (I'll read it through later). isn't Mr Heyser saying something pretty similar to what you, I, Frank and a few others have been saying all along and for what we got blasted by the objectivist fedayeens, namely that you CANNOT measure everything?
The gall of the man!
.Actually, Mr Heyser is saying very strongly on the contrary, ie that all things can of course be measured, BUT this requires different forms of measurements, or at least different/extended forms of analysis.
IOW, thinking well beyond the time honoured simplistic measurement methodologies such as FR, THD, and IMD.
One major concept he relates is that of spectral time distortions...ie devices/systems having differing throughput delay versus signal frequency.
This signal throughput delay can have its own 'spectrum', and this delay spectrum can further be signal dependent dynamically modulated.
This behaviour sets up a whole cloud of ''IMD/modulation'' like behaviour, with new 'foreign' frequencies/signals consequently produced.
He also discusses other 'non traditional/not usually considered' modulation causes, each producing another 'set' of 'foreign' frequency/spectral resultants.
This is just touching on what he is on about....read Audio Magazine: proposed series Chapter 11 - Conclusion, and then read it again !.
Once that chapter is digested, read Chapters 1 through 10, and read them again also.
The whole lesson revolves around the concept of 'energy', and not just 'signals'...the two terms are not the same thing.
More later.
Dan.
If its a flatbed you have a basic 2 axis CNC machine, I had an old Roland from work that I fixed a cheap Dremmel and played around with it. No Z-axis control, just up or down so had to set that manually with shims. Got rid of it because of no room, but fun to play with when I had the time.
The gall of me also
Actually, Mr Heyser is saying very strongly on the contrary, ie that all things can of course be measured, BUT this requires different forms of measurements, or at least different/extended forms of analysis.
IOW, thinking well beyond the time honoured simplistic measurement methodologies such as FR, THD, and IMD.
Hear, hear, I think Mr. Heyser was on occasion a devil's advocate just to stir the pot. I can see him irritating the more smug single minded objectivists. Remember he was not around for the likes of Peter Belt, Shakti stones, and brilliant pebbles. Saying that he might defend the garbage physics behind some of these is an insult to his memory.
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I think it is fair to say that he was comfortable with taking note of sensible subjective descriptions, but was not tolerant of BS.
Dan.
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Normal Programming Will Return In A Moment....
Hi Scott, referring back to the bridge 1/f noise measurement rig, AD524 was mentioned.
I can get hold of these for $15.00 delivered.
The jumperable precision internal gain setting resistors is one attraction.
Would you recommend a more recent INA, ADI or otherwise, or stay with the AD524 ?.
Dan.
Hi Scott, referring back to the bridge 1/f noise measurement rig, AD524 was mentioned.
I can get hold of these for $15.00 delivered.
The jumperable precision internal gain setting resistors is one attraction.
Would you recommend a more recent INA, ADI or otherwise, or stay with the AD524 ?.
Dan.
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We talking about orbiting missiles here or some audio snake oil I have not heard of? Admittedly getting funding for that project was an amazing display of BS by the companies involved and worthy of hi end audio.
Hi John
Your welcome, I think anything that helps give him the credit he deserved is worth doing.
In looking through his writings I really have to admire his ability to see things differently. He wrote that we use frames of reference to better grasp things but nature has none, they are our construction.
A great example of that frame of reference limited view is the impulse response which many think is the behavior of the driver / system. As Dick saw the speaker, it had an energy vs time curve describing the amplitude envelope in time. He also saw that energy time curve in 3d, the Heyser spiral which displayed the amplitude, phase and time of that energy.
The “real” part of that is the Impulse response, the quadrature view of that envelope, the Doublet response. Humorously, what you see what you look at an ETC or impulse response is a “white spectrum” view or equal energy per Hz view and not a “pink spectrum” view or equal energy per octave which would show all frequencies with equal visual representation.
The hard part about his writing for me is the math, I am a bulldozer chasing a butterfly with math, I measure things, see / visualize things in my head, then struggle to figure out the math. I have known a couple people who apparently had a calculator in their brain and “saw” math, I am not one of them, math is hard.
The “Great Pretender” was good and like a circuit with “leading phase” could appear to be waveform anticipatory but in reality no circuit or measurement “knows in advance” what happens when presented with a random signal because the idea of frequency isn’t valid until he signal has existed ‘long enough”
Meanwhile our brain / hearing system occasionally thumbs it’s nose at “how things work”;
Human hearing beats the Fourier uncertainty principle
Hi Sy
Yeah I am moving out of the area, at least for a while. They have wanted me to move since the beginning but now my kids have grown up, work is taking off and It’s getting harder and harder to work this far away.
I can design stuff anywhere but too often I need to measure something or troubleshoot and they can’t always do it at the shop. The boxes are often too big to ship, or have in a living room now days haha.
They found a real nice place for me, I can make lots of noise, have a lot of space and a large workshop and have plenty of room for my antique engines.. I said stop your hurting my arm, OK haha.
I remember at one point we talked and I was going to have you come over to hear some of these single point radiation synergy horns as you weren’t far away. I am sorry I didn’t get around to that, but if you’re down in the Gainesville / Dahlonega Ga area, I would be able to soon.
Hi Nelson
AT risk of further clouding the V or I water but if one has an efficient horn, one normally gets a better response curve IF it is driven by similar impedance, not a Voltage source, not a Current source.
The reason is if one had a perfect horn that was say 50% efficient, the impedance curve where it was 50% efficient would look like a resistance that was 2 times the drivers Rdc. Half of the power is lost to I^2 Rdc heating, half delivers into the acoustic resistance that appears in series.
Now, if the horn isn’t perfect, like real horns, it will have some bumps and wiggles and just like Antenna loading, if your acoustic load Z goes up by 2 and down by a factor of 2, the output changes less due to that change driven by a equal average impedance source than a Voltage source. I know horns have some following in hifi, maybe that is an idea application for the amplifier?
Hi fas42
Yeah what can be measured?? The very same Dick Heyser spent much of his last time trying to tie what we measure to “what it sounds like”, a map as he called it.
I am convinced that the huge fat gap between what we hear and measure has partly to do with using a measure that doesn’t track what we hear like THD. THD made sense in RF where any signal outside your band is bad, made some sense when all amplifiers distorted similarly but at it’s root, is not weighted according to each orders audibility vs frequency, does not take into account masking or the equal loudness curves. If you take enough measurements you can start to guess what a speaker will sound like before you hear it.
What I am fascinated with and think is the overlooked area is how our brain assembles a single image from two inputs and how a single loudspeaker radiates or can radiate a different things to each ear, that if present allow you to “hear”/ triangulate / localize how far away the speaker is, that gives it spatial identity. Conversely, if an identical sound is presented to each ear (like sound coming from far away, nearly a plane wave or simple source), you can’t identify it’s distance with your eyes closed.
Best,
Tom
PM me I'll send some, SSM2019 might be better or the new one AD8229. AD624 has lower noise too and keeps the preset gains.
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