Yes, the "man in the street's" prevalent notion of what 1.5W of coherent optical power would amount to is certain to be a gross underestimate.
Reminds me of the sophomores who decided to do an experiment to determine the threshold of sensitivity for electricity sent into the skull via electrodes. And they knew a little bit about prepping a subject for EEGs. Apparently their minimum initial voltage was almost instantly fatal, based on the high conductivity and location of the electrodes. So it goes.
If one considers a circuit as a mere assembly of parts in which the parasitics are considered of low importance, then relatively a trivial exercise. However, if every aspect one can think of that may impact the real-world performance is taken into account then it becomes a very involved exercise; the chip amps bits occupied about 1% of the space used ...
The point being, I worry about the "seemingly less important" aspects - because that's what counts ...
As John said, nice input ... . Over the years I've contemplated all sorts of tests, and put them up in posts on forums. And of course they were always completely ignored ...
So until people hear precisely of the type of test they can easily wrap their head around, this process will continue ...
For the hell of it, I'll mention another that I already talked of a number of times - this is of course is pure hand waving, and totally useless,
- a stereo power amp, stress one channel savagely to varying degrees, into particularly nasty loads on a continual basis, and at the same time test the other channel conventionally for sensitive IMD, etc, behaviours. Again, stressing the power supply, plus injecting lots of internally generated interference into the mix.This of course is of no relevance to an engineer ...
Over the years I've contemplated all sorts of tests, and put them up in posts on forums. And of course they were always completely ignored ...
...this is of course is pure hand waving, and totally useless,
Now you're getting the point. Handwaving is cheap and easy and requires no particular knowledge or ability or experience, just... air.
John and Frank,
It would appear that we have many different methods to measure distortion of all kinds. It isn't that we can't get this type of information, but what it truly tells us in the end that seems to be the question. I am sure that you can find multiple amplifiers with equivalent power output that have very similar distortion measurements and if you listened to each they would all sound different. Those differences are what becomes not only hard to quantify, but also to correlate with what sounds more accurate in the end. I think that what we are looking at in most cases are single time slices of the actual output from a device rather than a longer time frame showing what is happening in the time domain. When we attach any of these devices to a set of speakers this is when it becomes so much harder to predict what is going to happen. By distortion measurements alone we can probably say a particular electronic package will sound okay. But we can't say it will sound a specific way until it becomes a completed package hooked to a speaker system. We have no particular reference standards that we can use at that point. There are as many speaker types and implementations as can be imagined and all will sound uniquely different from each other. This is the paradox of audio. the only reference that we have is a live event vs a recreated event and how do you quantify that?
It would appear that we have many different methods to measure distortion of all kinds. It isn't that we can't get this type of information, but what it truly tells us in the end that seems to be the question. I am sure that you can find multiple amplifiers with equivalent power output that have very similar distortion measurements and if you listened to each they would all sound different. Those differences are what becomes not only hard to quantify, but also to correlate with what sounds more accurate in the end. I think that what we are looking at in most cases are single time slices of the actual output from a device rather than a longer time frame showing what is happening in the time domain. When we attach any of these devices to a set of speakers this is when it becomes so much harder to predict what is going to happen. By distortion measurements alone we can probably say a particular electronic package will sound okay. But we can't say it will sound a specific way until it becomes a completed package hooked to a speaker system. We have no particular reference standards that we can use at that point. There are as many speaker types and implementations as can be imagined and all will sound uniquely different from each other. This is the paradox of audio. the only reference that we have is a live event vs a recreated event and how do you quantify that?
1. There is no practical way I know of to distinguish between what the ear-in-itself picks up and between what the brain-mind-in-itself picks up. We cannot measure a human ear, detached from a brain-mind. If you know better, please share.
2. We are dealing here with audio reproduction, mostly music.
When listening to live music, the brain-mind is involved, as much as the ears are involved.
Therefore, when dealing with the quality of reproducing music, discarding the impact the brain-mind has on the joy of listening to music equals to blinding oneself to a major contributor to the phenomenon (listening to music, live and reproduced alike).
Is the above proved scientifically, or is it only your inner conviction?
Do you refer here to what you hear, or to what others report hearing?
I have no idea what to do about others.
I have no idea why you are concerned with others, what others actually hear, or don't hear.
Potentially, you may do you yourself a service should you be concerned with what *you* hear and what measurements may reveal what *you* hear,
Now, if you hear nothing that isn't being shown in the measurements you already do, than there is no issue for you. You can go on living your life and enjoying reproduced music in you present audio setup, happily ever after.
However, suppose there are *actual* phenomena others hear, while you don't hear it, you'll never be able to know whether what others report hearing are actual phenomena, or only their imagination, or any combination of both. I'm referring to actual knowing, based on scientific methods – not to any inner conviction which isn't proved in-itself, scientifically. Getting at conjectures, based on scientific data which may, or may not correlate directly to the phenomenon in question, isn't a scientifically-based knowledge.
Of course there is. Ears-only testing, level-matched, no peeking. How many times does this need to be said?
A nice coincidence: this, http://www.diyaudio.com/forums/soli...lls-power-amplifier-book-300.html#post3485763, perfectly exemplifies what I'm talking about. No matter what the skill level of the practioner is, this can just happen totally unintentionally, and is something that is not easily explainable to normal engineers. And I've been chasing it down for over 25 years, .
First person to correctly state what occurred gets the prize ...
.First person to correctly state what occurred gets the prize ...
And one must ask, Zen-like, what is the sound of one hand waving?Well, you DO need one hand, minimum.
Good input, Kindhornman ...
I've resolved the "paradox", to the bemusement of many, by a very straighforward technique which has always worked. I repeat, always worked. Difficult recordings are a dead easy giveaway to what's wrong, every deficiency of your system screams at you, the sound is unlistenable to because its distortion characteristics intermodulate with those on the recording and the end result can be unbearable.
So, you work on those areas which reduce that unpleasantness, without discarding the ability to resolve detail; if one does that correctly the system keeps improving: good recordings stay good, get better in fact; and the "poor" recordings keep getting easier, more satisfying to listen to.
You don't. You just evaluate what your ears tell your mind, without conscious or unconscious non-auditory cuing. It's what your ears actually hear, not what your lying brain thinks the ears hear.
If you just want to know what acoustic waves are hitting your ear, that sort of measurement uses an obscure modern device known as a "microphone." It's a marvelous device and not difficult to use. Even dumb chemists like me can manage.
The guy that developed Teradyne's first laser trim stations has at least 3/4 of one retina missing. The story I got was absent mindedly sighting down the line on a 30W IR laser. The norm for trimmers is to start with a huge power and attenuate it to a tiny fraction, obviously you don't need much to cut those tiny thin film resistors.
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It is what I wrote, that one cannot disconnect the ears from the brain-mind - when you wrote one can.
There are many assumptions here, more unanswered questions than answered ones.
For instance:
What is it that impacts the brain-mind one way or another in appreciating music?
How do you make sure that out of what impacts the brain-mind one way or another in appreciating music, nothing isn't being altered during this test?
Is the subject's possible tests-anxiety neutralized?
If yes, how?
Is the subject being asked to listen to anything specific, like sound details, or music appreciation?
1. There is an unproved assumption here that sound waves are the only thing that affects music appreciation.
2. No microphone in the world is perfect (yet), as much as no existing test gear is perfect (yet).
its a handwaving convention...
they are, the other half of the problem is the mind/body, but just because we dont yet understand the mind fully, does not mean that we havent reached a point, at least in the box, that is beyond our ability to perceive it. funnily the main areas in hardware I feel are left, are the transducers and room, but Frank reckons these are sorted and the problems are in the electronics...
and what exactly has that got to do with anything? we need only exceed our ability to hear, that was done loooong ago.
they are, the other half of the problem is the mind/body, but just because we dont yet understand the mind fully, does not mean that we havent reached a point, at least in the box, that is beyond our ability to perceive it. funnily the main areas in hardware I feel are left, are the transducers and room, but Frank reckons these are sorted and the problems are in the electronics...
and what exactly has that got to do with anything? we need only exceed our ability to hear, that was done loooong ago.
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