It's all entertainment, even Audio Science Review...
I can imagine an architecture magazine with an odd name like Brickophile where they measure different houses and loft rooms with always the same loudspeaker set. At the end there would be an edition fall of the best architecture house to listen to music ! Of course the loudspeaker will be a very cheap one.
all entertainment, architects must laugh at reading us : "it's the room baby..."
all entertainment, architects must laugh at reading us : "it's the room baby..."
747-class airplanes have glided to a safe landing.
Gimli Glider
"Air Canada Flight 143, commonly known as the Gimli Glider, ....ran out of fuel on July 23, 1983, at an altitude of 41,000 feet (12,500 m), .... The flight crew successfully glided the Boeing 767 to an emergency landing that resulted in no serious injuries to passengers or persons on the ground,..."
"Flying with all engines out was never expected to occur, so it had never been covered in training."
"In 10 nautical miles (19 km; 12 mi), the aircraft lost 5,000 feet (1,500 m), giving a glide ratio of approximately 12:1 (dedicated glider planes reach ratios of 50:1 to 70:1)."
AND: https://simpleflying.com/gallunggung-glider-the-story-of-british-airways-flight-9/ 747-200 and volcanic ash
As for the Wrights-- if the maximum height of the flight is not much more than the height of the pilot, an altimeter may not be needed.
And the Gimli Glider had no working altimeter for some part of the glide; and altitude management is critical to a glider.
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Measurements don’t tell much about how we will like the sound. Imagine you have zero distortion system. Will it sound best of the best. Most likely not. Distortions linear and non linear are like a salt and peper on a stake. Adding them in a correct way makes stake tasty.
Thats why we should rely on measurements and try to make zero distortion system. And leave distortions and effects for musicians and sound engineers. It’s a creative part. How added effects/ distortions correlate to perception is to complex question.
Even two zero distortion speakers linear and non linear distortion will sound completely diferent if they are flat in FR but diferent in power response.
Once i have done DAC and left some mistakes, and THD was worse than -70db. But it sounded good. After fixing problem i got well below -100db but subjectively it sounded worse. Salt and peper…
Thats why we should rely on measurements and try to make zero distortion system. And leave distortions and effects for musicians and sound engineers. It’s a creative part. How added effects/ distortions correlate to perception is to complex question.
Even two zero distortion speakers linear and non linear distortion will sound completely diferent if they are flat in FR but diferent in power response.
Once i have done DAC and left some mistakes, and THD was worse than -70db. But it sounded good. After fixing problem i got well below -100db but subjectively it sounded worse. Salt and peper…
Even if I fully agree with your all arguments please note that my "flapping wings" was a play on words (failed because English is not my first language and it is clear that the wings of a plane do not flap at all).
I was going to play a word game first of all because this thread was published on "The Lounge" and therefore it is not only strictly technical and then because I'm just noticing that sometimes what is said is taken literally while sometimes it could be interpreted not to the letter. IMHO
Just as an example, when I said that the Hi-Fi does not exist I intended to summarize all those exceptions and those customizations that make each audio-system different (often, heavily different) than another one in the technical type and in the number of components and in so many other things and finally in sound.
If the above were only at least partially true, then it is clear to me that Hi-Fi cannot exist being a theoretical concept (a so vey important concept) that nevertheless manages to bring together millions of people in the world with the same passion: listening to Music.
Yet the quality of the devices and their circuit topology and technical typology and components level are in a qualitative range starting from lowest to excellent (or vice-versa), that's why I said that I like to listen to Music through a High Quality system rather than an High Fidelity one.
Also because it's obvious that quality is a characteristic of crucial importance in any product category, from food to cars, from clothing to watches.
Everything, all is built according to a level of quality.
There are economic watches and very expensive watches, yet both simply measure time (yes I know they can be a status-symbol too).
Indeed, the very cheap one could be quartz-crystal-regulated and even be very precise, even more precise than the expensive one, but who wants it?
Maybe it's ugly, maybe it's not reliable, maybe it breaks soon, maybe it's dangerous for poor materials, but its price is very low.
The choice is yours (relating to what you can afford to spend or how much you have decided to spend).
Speaking of Audio equipment then things remain the same.
How much the manufacturer is able to make you pay for a certain level of quality is totally a different thing.
So, I like to identify the best value-for-money of a piece of audio equipment in any class of price.
As an example, if I want the Quality (I did not say the Fidelity) of a preamplifier for which I'm willing to spend 3,500 bucks, then I'm committed to finding a device that for that price gives me the constructive quality that I like, the technical typology that I want, if possible the aesthetic that I prefer, excellent measurements for the peace of the mind and most of all the sound that I want in my system, then I buy it and that's it.
Knowing that I bought Quality, not Fidelity.
Actually, they don't use 41,000 feet altitude for airplane navigation purposes. They use FL140, which is an air pressure reading, not an altitude. Below the transition altitude in the local airspace jurisdiction, altimeters are adjusted to read altitude based on air pressure at ground level (often measured at some local airport). Other means can be used to get altitude such as GPS and or inertial navigation systems. Some airliners use multiple means of determining altitude and location, and compare the various systems for consistency. https://aviation.stackexchange.com/...-difference-between-flight-level-and-altitude
I wasn't there. All I know is what I read. I attributed that quote just so I would not get blamed for inaccuracy.
Fair enough. For anyone interested, and since the issue was raised, more info on what to do when the gas runs out: https://www.faa.gov/news/safety_briefing/2018/media/SE_Topic_18-05.pdf
And the record for gliding a brick goes to:
https://simpleflying.com/azores-glider-the-story-of-air-transat-flight-236/
https://simpleflying.com/azores-glider-the-story-of-air-transat-flight-236/
Its not just those two types, there are also non-time invariant and or nonstationary to consider. An AP machine only tests with steady state test signals, so we only get numbers for what is presumed to be time-invariant linear and or nonlinear distortions (mostly of the focus seems to be on time-invariant nonlinear distortion, especially without regard to phase and or crest factor, not to mention presumed to be a time-invariant noise floor). Its the other types we typically don't measure that may have more to do with why we may like the sound of certain audio devices. And that's just for things like amplifiers, devices that are no more than 'weakly' nonlinear and or 'weakly' non-time invariant. DACs are a whole different thing because there can be RF noise and or more than weakly non-time invariant effects going on that don't show up very well in typical audio FFT analysis.
I think all mentioned is time-invariant systems. Meaning that output on friday will be the same as on monday for the same input signal.
Not sure exactly what you mean by that?
For me at least, as a simple example of a time-variant system, possibly helpful to consider the following system input and output waveforms.
They are of an audio compressor (apparently in this example with some digital look-ahead attack behavior), not an amplifier. However seems to me something similar (but without digital, nor analog delay line, look-ahead), yet more subtle could occur in some amplifier topologies (perhaps, say, one with loose-ish power supply regulation). The point illustrated in this particular example is that of gain change with dynamics transients. Obviously, measuring distortion with a fixed level sine wave won't reveal exactly why the output sounds the way it does.
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Here is another example of possible gain variation when an analog compressive effect exists (just to illustrate types of effects that could potentially occur, obviously shown much more dramatically here than would be expected from an amplifier with some type of compressive behavior).
Aside: One way to measure such effects using a stepped-gain test signal and a digitally acquired sample set might be through application of the Hilbert Transform, which can be used to derive a signal-level envelope waveform.
Aside: One way to measure such effects using a stepped-gain test signal and a digitally acquired sample set might be through application of the Hilbert Transform, which can be used to derive a signal-level envelope waveform.
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These examples are cleary distorting systems. Distortionless system when output folows input. Let’s don’t talk about signal shape.
I was refering to that theoretical distortionless systems will sound different. I ment on axis free field distortionless system. Polar responses will be different for diferent speakers. And bringing them into the room the sound field they create will be completely diferent. They will sound diferent.
I was refering to that theoretical distortionless systems will sound different. I ment on axis free field distortionless system. Polar responses will be different for diferent speakers. And bringing them into the room the sound field they create will be completely diferent. They will sound diferent.
No, and they made a TERRIBLE plane, closer to a kite than anything else.
Any modern plane, infinitely superior, came to be through measurements and calculations.
And even so, on Wright´s FIRST plane, LOTS of Math were used to make it possible.
Copypasting:
"Design and construction
The Flyer was based on the Wrights' experience testing gliders at Kitty Hawk between 1900 and 1902. Their last glider, the 1902 Glider, led directly to the design of the Wright Flyer.[5]
The Wrights built the aircraft in 1903 using spruce for straight members of the airframe (such as wing spars) and ash wood for curved components (wing ribs).[6] The wings were designed with a 1-in-20 camber. Since they could not find a suitable automobile engine for the task, they commissioned their employee Charlie Taylor to build a new design from scratch, a lightweight 12-horsepower (9-kilowatt) gasoline engine, weighing 180 pounds (82 kg), with a 1-US-gallon (3.8 l; 0.83 imp gal) fuel tank.[7] A sprocket chain drive, borrowing from bicycle technology, powered the twin propellers, which were also made by hand.[5] In order to avoid the risk of torque effects from affecting the aircraft handling, one drive chain was crossed over so that the propellers rotated in opposite directions.[8] According to Taylor:
They figured on four cylinders and estimated the bore and stroke at four inches. It took me six weeks to make that engine. The completed engine weighed 180 pounds and developed 12 horsepower at 1025 revolutions per minute...The body of the first engine was of cast aluminum, and was bored out on the lathe for independent cylinders. The pistons were cast iron, and these were turned down and grooved for piston rings. The rings were cast iron, too. A one-gallon fuel tank was suspended from a wing strut, and the gasoline fed by gravity down a tube to the engine. The fuel valve was an ordinary gaslight petcock. There was no carburetor as we know it today. The fuel was fed into a shallow chamber in the manifold. No spark plug. The spark was made by opening and closing of two contact points inside the combustion chamber. Dry batteries were used for starting the engine and then we switched onto a magneto bought from the Dayton Electric Company. There was no battery on the plane. Several lengths of speaking tube...were used in the radiator. We blocked-tested the motor before crating it for shipment to Kitty Hawk."[9]
The 8.5 foot (2.6 m) long propellers were based on airfoil number 9 from their wind tunnel data, which provided the best "gliding angle" for different angles of attack. The propellers were connected to the engine by chains from the Indianapolis Chain Company, with a sprocket gear reduction of 23-to-8. Wilbur had calculated that slower turning blades generated greater thrust, and two of them were better than a single blade turning faster."
So much for your antiscientific assumption that "Math and Measurements are worthless or not needed"
"Sophisticated altimeter"?
Don´t be ridiculous, all they needed is to know they were flying above ground level, and that is easy to see by the naked eye.
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Sir, please provide a link to anywhere you claim I have stated such an assumption.
And that is truly remarkable. Jumbo jets require engine power to slow down enough to land on a typical runway. They have to put their flaps way down for enough lift, and have to gun the engines to compensate for the added drag. Without engine power, they have to land at a very fast velocity- a risky situation - and then have enough runway to stop from that high speed without reverse thrust.
I remember reading about a jumbo jet landing without power. It landed way too fast (unavoidable) and ran off the runway "in the weeds" and then overshot the runway and hit a barrier. Nevertheless, injuries were minimal.
You have to give the flight crew a lot of credit.
Actually, the big wide-body jets are as good or better gliding without power than many light aircraft. The Space Shuttle was pretty much the bottom of the list at some 4.5 for subsonic flight & approaches, Two to One transonic and a One to One ratio at ultra-sonic speeds.
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They still need a very long runway. Plus many pilots (most?) have no training or experience with this.
It constitutes a very grave situation when there's passengers involved. It's quite likely to result in a crash landing. Even the successful one I read about was very scary and the outcome was uncertain.
It constitutes a very grave situation when there's passengers involved. It's quite likely to result in a crash landing. Even the successful one I read about was very scary and the outcome was uncertain.