audiofools...maybe not so much

[alho]

For ASMR I'm using 20€ Scullcandy headphones and crappy laptop, so crappy that it's spewing noise from CUP power electronics and USB bus to audio output. Nothing near audiophile quality is needed for ASMR. If I find my sub 5€ headphones I'll test if theres any difference. Probably not.

A large part of this phenomenon seems to involve people experiencing a sense of relaxation as a result of hearing different "trigger sounds". Usually these include soft whispering, clicking noises, crinkling paper, hands rubbing across cloth, etc. The commonality among these things are that they're all sounds with very high frequency harmonic components.

It not just a matter of sound. From looking posts at http://www.reddit.com/r/asmr/ it seems that for many visual and social triggers are important. Also music seems to be very unpopular for ASMR. r/asmr/ has 62k subscribers while r/ASMRmusic has 900. And what does most post at /r/asmr/ and r/ASMRmusic have common? Almost all are links to youtube. Might not be best source if you are looking for audio with very high frequency components.
ASMR has nothing to do with audiophilery because it isn't repeatable instant on/off thing. It wouldn't be very good if your 10k$ gold plated unicorn hair cable would work well only sometimes and with delay of several minutes.

What I'm going to posit is that many audiophiles may be hyper-sensitive to sounds at the limits of human hearing in the higher frequency ranges.  If there's even the slightest amount of ringing on the supply rails or very high order harmonic or IMD products, is it possible that they may be picking up on this and creating a sense of relaxation or agitation depending on the specifics of the content? So when these paleolithic emotions get triggered it's possible that they could be making a subconscious qualitative instead of quantitative decision about the goodness (relaxation), or badness (tension) of the sounds they're hearing.

I don't think that I've ever experienced anything unpleasant in similar way to ASMR, you could post question to reddit and see if you find someone who has. Perhaps sensory processing disorder http://en.wikipedia.org/wiki/Sensory_processing_disorder#Hyposensitivities_and_hypersensitivities would explain agitation caused by hypersensitivity to sound better than ASMR. But if someone is hypersensitive to high frequency sounds why would it only happen with audio equipment. Shouldn't audiophiles walk around with sound mufflers on their ears so they don't get agitated. After all there is lots of high frequency sounds out there.

[Sigmoid]

I don't think that I've ever experienced anything unpleasant in similar way to ASMR, you could post question to reddit and see if you find someone who has.

Never??? Have you ever had a teacher draw his nails across the blackboard at school?

[scientist]

They fantasize about headphones. I'd say that's foolery.

[VK5RC]

Earlier in this blog a comment of not hearing in 5.1 was made,  the external ear gives to sounds arriving from different directions a different spectra,  the ear does a simple fft,  this is easily tested,  block one ear,  blindfold and have a friend click his fingers  in different positions,  typical accuracy is better than 5 degrees with ONE EAR,  While a lot of audiophile stuff is rubbish,  some of the really complex analysis has not been done. (All silicon PA at home here!)

[alho]

I don't think that I've ever experienced anything unpleasant in similar way to ASMR, you could post question to reddit and see if you find someone who has.

Never??? Have you ever had a teacher draw his nails across the blackboard at school?

Nails on blackboard sounds unpleasant instantly and I don't feel nauseated for 10 minutes afterwards witch makes it different from ASMR.

Tom Stafford, a professor at the University of Sheffield, says, "It might well be a real thing, but it's inherently difficult to research."

That's normally code for "I think it's bullshit but its not worth my time to prove it to you". I've seen our dean of medicine saying essentially the same thing about homeopathy. I've said the same thing to people asking about astrology. It makes them go away.

Here is the full quote:

It might well be a real thing, but it's inherently difficult to research. The inner experience is the point of a lot of psychological investigation, but when you've got something like this that you can't see or feel, and it doesn't happen for everyone, it falls into a blind spot. It's like synaesthesia – for years it was a myth, then in the 1990s people came up with a reliable way of measuring it.

I used to think that it happened randomly and was normal for everyone. Until few years ago I found out that its called ASMR and that it can be actively triggered and isn't common. Not the sort of thing that comes up at coffee table conversations. 

Also from wikipedia:

Steven Novella, Director of General Neurology at the Yale School of Medicine and active contributor to topics involving scientific skepticism, wrote in his online neuroscience blog about the lack of scientific investigation on ASMR, saying that functional magnetic resonance imaging and transcranial magnetic stimulation technologies should be used to study the brains of people who experience ASMR in relation to people who do not experience ASMR. Novella discusses the concept of neurodiversity and mentions how the complexity of the human brain is due to developmental behaviors across the evolutionary time scale. He also suggests the possibility of ASMR being a type of pleasurable seizure or another way to activate the pleasure response.

I would be very surprised if ASMR wouldn't show up on MIR. Its way too pleasurable to not have measurable effects on brain.
Anyways, good luck getting research funds to study some obscure phenomenon with very little scientific evidence.
It seem to me that fairly constant stimulus causes increasing effect, so maybe its some flukey feedback loop in nervous system.
It might have something to do with social grooming behavior. From wikipedia: "Grooming stimulates the release of beta-endorphin, which is one physiological reason for why grooming appears to be relaxing". An example of common AMSR video title would be something like "Roleplaying girlfriend gives hair cut while whispering softly". But I skip anything that even hints at roleplay and go for random noises or something instructional so... who knows?
 

Even if he didn't mean it that way, even he was convinced there is a real effect

If my head tingles and I feel like I'm floating for 20 minutes or so, I don't really care if its caused by real effect or not. And it's free. Well I did buy a t-shirt to support ASMR related youtube channel, but it's still way cheaper than becoming an audiophool.

[Sigmoid]

Earlier in this blog a comment of not hearing in 5.1 was made,  the external ear gives to sounds arriving from different directions a different spectra,  the ear does a simple fft,  this is easily tested,  block one ear,  blindfold and have a friend click his fingers  in different positions,  typical accuracy is better than 5 degrees with ONE EAR,  While a lot of audiophile stuff is rubbish,  some of the really complex analysis has not been done. (All silicon PA at home here!)

I didn't say that isn't true. What I said is that good stereo can replicate everything 5.1 can. I've heard some pretty damn amazing stereo...

The reason 5.1 was invented was cinema. Stereo only works if you control the position of the speakers relative to the listener. It's essentially a one-person affair, and doesn't hold up in a cinema, with people sitting all over the place.

[linux-works]

just wait until 'object oriented audio' hits mainstream.  (dolby labs is working on it; I interviewed there and got a glimpse of what they are heading toward).

the idea is that you design audio for movies without tying it to the # of spkrs at playback time.  you can create x,y,z points in space where the should 'should 'come from, then describe that in the meta audio file for each sound.  there could be a virtual audio track for every single discrete sound along with the xyz mapping function of where it should 'slide to' over time.

at playback time, you translate this set of spacial stuff down to the number of real spkrs you have (like 'rendering' in graphics).  this is the harder realtime part and I've seen some impressive rackmount audio processing that does this.

I love the idea: you create sound with spkr-independance and then map to them based on YOUR playback system.  this would mean that all individual data is kept unmixed until the very final stage.

this isn't about high end audio, but talking about 5.1 (etc) reminded me of this new 'OO' based audio approach.  it will also mean a whole new ecosystem of tools to create the sound files, edit them and render them at the final stage.

[NiHaoMike]

just wait until 'object oriented audio' hits mainstream.  (dolby labs is working on it; I interviewed there and got a glimpse of what they are heading toward).

the idea is that you design audio for movies without tying it to the # of spkrs at playback time.  you can create x,y,z points in space where the should 'should 'come from, then describe that in the meta audio file for each sound.  there could be a virtual audio track for every single discrete sound along with the xyz mapping function of where it should 'slide to' over time.

at playback time, you translate this set of spacial stuff down to the number of real spkrs you have (like 'rendering' in graphics).  this is the harder realtime part and I've seen some impressive rackmount audio processing that does this.

I love the idea: you create sound with spkr-independance and then map to them based on YOUR playback system.  this would mean that all individual data is kept unmixed until the very final stage.

this isn't about high end audio, but talking about 5.1 (etc) reminded me of this new 'OO' based audio approach.  it will also mean a whole new ecosystem of tools to create the sound files, edit them and render them at the final stage.

Games already do that, in real time nonetheless.

[linux-works]

how many spkrs can 'games' render to?

at dolby, they were talking about having this scale to hundreds of spkr drivers.

games that have audio that 'does not matter' is one thing.  high quality audio from a respected audio company that does real science and r/d is QUITE another.

[AndyC_772]

Sounds like a solution looking for a problem to me. Don't forget that it's very much in the commercial interests of companies like Dolby to come up with new products, whether there's a genuine market need for them or not.

I can't remember the last time I went to see a movie at the cinema and thought "what this film really needs to bring it alive is a hundred speakers". In many cases, a properly focused picture and a sound system that's at least as good as the one in my living room would be a good start, and might go some small way towards justifying the ticket price.

[linux-works]

personally, I hate multichannel movie sound.  at home, I down-map the 5.1 nonsense to linear spdif stereo audio (so that I can send pure digital spdif into my crossover and keep the signal all 24/96 up until the final set of DACs).

I can see the value in what they are doing, though; I'm in the minority and many younger folks love multichannel sound.  they bought into it.

and mastering for a fixed # of spkrs seems like the wrong approach when you can develop the sound stage independant of discrete playback devices and then map on a site-specific way, as needed.

I do like the inventiveness of this even though I will likely not ever run multichannel stuff at home.

[JuiceKing]

I've been to a bunch of high-end stereo shows, and the sound of the different stereos is DRAMATICALLY DIFFERENT!

You'd think that if the goal of audio equipment is to reproduce sound faithfully, that their performance would converge as price goes up. But it's quite the opposite. You can't charge more for something that sounds the same. These systems are different by design.

I think most are very poor value for money, and the marketing is cooked up by fools and charlatans. But some systems sound just amazing and that's fun.

[Sigmoid]

personally, I hate multichannel movie sound.  at home, I down-map the 5.1 nonsense to linear spdif stereo audio (so that I can send pure digital spdif into my crossover and keep the signal all 24/96 up until the final set of DACs).

I can see the value in what they are doing, though; I'm in the minority and many younger folks love multichannel sound.  they bought into it.

Multichannel isn't a personal preference thing.
Its goal is to eliminate the need for all the magical speaker placement measurements and the "listening chair" bolted to the floor in the dead center of the room.

That said, I do not use multichannel, and downmap it myself to stereo. Nor do I have a listening chair. But I do own a good pair of flat response studio headphones for when it really counts.

[linux-works]

I've mostly given up -caring- about soundstage, to that level.  you move a little and the 'calibration' is off.  it just does not seem to make sense to me to sit motionless in the sweet spot.  so, I gave up trying for perfect imaging (with speakers).  recorded sound is always going to sound recorded and sourced from discrete non-real sources.  I'm ok with that, given that's just how it is.

[vk6zgo]

most people don't have golden ears, but some actually do.

I was demo'ing some audio gear (including spkrs) at a show and the spkrs were from someone else.  he told me that the red/black posts may not be right.  I connected it and used the spkrs anyway.

one guy came by and said he thought the absolute polarity was wrong.  I don't believe he was there when the spkr owner explained that to me.

could it have been just a coincidence?  maybe.  maybe not!

very few people are good 'test gear'.  I know I'm not.  but a select few really are!

I've run into a couple of cases of "people with golden ears" detecting a fault that the rest of us couldn't hear.

Some years back,I worked at a manned TV/FM Broadcasting Station in the middle of the Western Australian Wheatbelt.

The FM Station's was fed from two discrete Audio outputs of a UHF link,which in turn was fed by a long landline back to Perth.
The Stereo pair of lines were normally equal length.

One of the Techs told us there was something "funny"with the Stereo signal as heard through his home Receiver.
He said it sounded like one channel was out of phase.
We all listened,& couldn't hear anything wrong.

It turned out that the Long Line Techs had found a fault on one leg of the Stereo pair,& not realising it wasn't a Mono line,diverted it to an alternate feed which was around 100km longer,booked the faulty line for repair,& went on their way.

100km is a free space wavelength at 3kHz (probably a bit lower in that particular cable),& various fractions & multiples at other parts of the audio spectrum----definitely enough to stuff things up!

Why we didn't hear it?---Probably noisy environment,less than ideal speaker placement,etc.

The next episode was in a major city TV Station,where one Staff member reported he could hear a "hissing" sound on the TV stereo sound-----again on a home Receiver.

The Transmitters were used "day about",so it was easy to determine which one was responsible,but very difficult to reproduce his results.

We all listened at the Studio,at the Transmitter,& as far as possible,at home.
No sign of a problem!

We looked at the Sound Mod output with a Spectrum Analyser,all looked OK.
The SA was "battling" a bit to see anything that close to the Sound Carriers,but we tried!

No viewers complained,so we told him he had "golden ears" & had much innocent merriment "hissing" at him!
Abruptly,while I was on leave, the  "suspect"Sound Modulator failed,with spurii all over the place!

Much egg on many faces!

[ampdoctor]

Hmm, this did seem to spur on some interesting discussion.  For a bit of clarification on my end...

ASMR; Personally I could care less about the phenomenon. The reason I brought it up was that it was the impetus or a jumping off point for more serious thought regarding the psychology of how sound is interpreted. Are these psychological triggers part of a more universal way our brain interprets and processes audio? Why is there a near complete absence of low frequency content? It opens the door just a crack for some interesting hypotheses in other areas of study that might be loosely connected.

Audiophiles; It might have been better to say something along the lines of a few people in that "community", for lack of a better term, MIGHT be uniquely sensitive to things that the majority of the population miss.  Clearly in the aggregate they are playing the "mine is better than yours because it costs more" game, or any number of other psychological deficiencies, but isn't it possible that a select few just maybe.....

As vk6zgo noted there's no shortage of examples of people that you can point to and say "how the hell did he hear that?!" Obviously it's going to be difficult if not impossible to perform any empirical testing that would provide meaningful results, at least not at this point. And this is the area that keeps me curious and not willing to completely dismiss some of these observations as a purely psychological effect.

Now, let's say somebody sits down and designs a good class AB power amplifier. I think it's safe to assume that pretty much everybody will agree that crossover distortion sounds "bad", but the question is how bad do the distortion products have to be before they become unacceptable?  Moreover, do people hear some of the much higher harmonics and are just not consciously aware that they're hearing them? Or is it perhaps the combination of even and odd order harmonic content that some people are sensitive to? This could be part and parcel of why two people listen to the same system and one person says it sounds fine and another says it doesn't sound quite right. 

I'm not talking about anything unmeasurable here, I'm saying that it could be possible that human perception of the the world around them are more finely grained than what we give ourselves credit for.  We know that when somebody loses one of their senses the others become far more acute as a way to compensate for the loss. In the case of somebody who loses their sight, their sense of hearing becomes markedly improved. If the ability to hear to that degree wasn't there to begin with there would be no possibility for improvement. Most likely our brains just prioritize the incoming data and discards what it doesn't need for whatever reason. But the information is there just the same.

Obviously there are economies of scale that come into play when designing and manufacturing products far out on the tails of what we would consider normal. What's the point in producing a product who's differences can only be discerned by 1/10th of 1 percent of the population?! There's a strong argument for that, but if we think back on products from 50-75 years ago. Today we would consider the quality unacceptably poor, but when they were introduced we thought they were pretty amazing. So do we just sit idly by and say meh what's the point, or do we peer over the next mountain and see what there is to see?

And no we don't hear in stereo. At least not in the way it's marketed to us. We hear not only through out ear canals but also the bones in our skull and jaw as well. Our sinuses also play a role as well. Factor in the distance to the source as well as sound pressure levels. Now add in that lower frequencies are more omnidirectional and higher frequencies are more unidirectional. It becomes clear that there's a lot more going on than just left side of the room goes in the left channel and right side of the room goes in the right. The composite sound stage we experience is far closer to mono than it is to stereo. But that's a completely different discussion with respect to how music is/should be mixed and mastered from source recordings.

[JuKu]

Well we have two ears, so by definition we DO hear in stereo. At least the lucky majority of us.
We definitely do not hear in 5.1 surround though...

Actually, we do. In a study comparing the quality (in terms of envolvement, sense of being there, realism etc, specifically excluding artifacts, noise etc) versus number of channels, the quality went up almost linearily (!) up to 5.1 and logarithmically after that. In another study, the limit of audibility was found to be somewhere between 0.5 and 1 million channels(!). So, in theory and optimal conditions, you could hear a difference between 50000.1 and 500000.1 systems. Btw, the .1 is not enough either, we do sense dynamic bass direction: Did I kick you in the stomach, back or side? which side?

[JuKu]

Too much trouble to search for each writer and put the quote tags... Sorry. But a few points:

- Double blind: There are two problems with that. #1, a double blind test only gives a positive result: If there is a difference, it means that what was tested is indeed audible. But a negative test only says that with this material, this equipment, this room, these subjects did not hear a difference today. but that's it. With some other people/material/equipment/room there might be an audible difference. You can't prove "no audible difference". #2: Real life situations very seldom are blind. And the hearing sensation is real, even if it might only partly come from movement of air molecules. We know (as a proven, scientific facts) that color TVs don't sound as loud as B&W TVs but they have a better sound; black speakers sound better than red ones; big speakers have better bass etc.

- Measurements: I'm an engineer, so I believe in measurements. I also believe that we don't have enough knowledge about how humans hear to know what to measure. Besides, I haven't yet seen any audio equipment with different designs that measure equally(!). I can measure a zillion things and fine differences, but on many measurements, I don't know if those have any audible meaning. (A very, very simple example: This device has better channel separation than that one, but the leakage is asymmetrical. Which one has better stereo imaging?)

- Sometimes high end hifi can approach the illusion threshold, where you start to believe that you are hearing the real thing, not just a glorious reproduction. When there, I believe that different rule set applies; very minor thing can keep the illusion up or break it to a mere glorious reproduction.

- Some humans have indeed a different hearing than others. I am also much more sensitive in low frequencies than an average person. I don't have hyper-sensitivity, in the 500-2k area where normal people sensitivity is the greatest I'm average. But normally, the hearing sensitivity goes up when frequency goes down (Fletcher-Munson). I don't have that; at 200Hz I'm at least 20dB more sensitive than average people (the equipment range run out and I could hear the tram line rumble four blocks away leaking in the sound isolated test room).

[- Racial comment: The hearing capability differences might be genetic: There has been quite a few well done scientific studies showing the meaning of 30k-50k range in faithful reproduction from Japan, that have not been reproducible in US.)

- The listener might not be able to name the difference, even though s/he hears it. We once built two products to two brands. The products were otherwise identical, but to compensate a slight frequency response error in the other customer's power amp, the low-pass filter was tuned a bit lower in one of the products. The difference was 0.1dB at 20kHz, which I still believe should be inaudible by a wide margin. Still, the press (sometimes in comparison tests) gave comments about the other products high-end, like "Nothing is missing, but it is a bit smoother than X", far too many for me to believe those were random guesses.

[Sigmoid]

Audiophiles; It might have been better to say something along the lines of a few people in that "community", for lack of a better term, MIGHT be uniquely sensitive to things that the majority of the population miss.  Clearly in the aggregate they are playing the "mine is better than yours because it costs more" game, or any number of other psychological deficiencies, but isn't it possible that a select few just maybe.....

As vk6zgo noted there's no shortage of examples of people that you can point to and say "how the hell did he hear that?!" Obviously it's going to be difficult if not impossible to perform any empirical testing that would provide meaningful results, at least not at this point. And this is the area that keeps me curious and not willing to completely dismiss some of these observations as a purely psychological effect.

A scope will "hear" everything. There are companies that use solid science to make good-sounding devices (such as Dolby), and there are industries where quality is paramount and professionals who can hear a channel out of phase (sound technicians are generally an object of my admiration).
But all this has nothing to do with audiophilia, which has absolutely no relation to reality, or anything measurable.

It becomes clear that there's a lot more going on than just left side of the room goes in the left channel and right side of the room goes in the right. The composite sound stage we experience is far closer to mono than it is to stereo. But that's a completely different discussion with respect to how music is/should be mixed and mastered from source recordings.

Huh? I don't get what you're saying. First you say there's a lot of directional info we perceive, and then say our hearing is more like mono? Could you elaborate?

Anyway, good stereo is a LOT MORE than "left side of the room goes in the left channel and right side of the room goes in the right".
This is equivalent to "left side of the room goes in the left channel and right side of the room goes in the right":
http://en.wikipedia.org/wiki/File:Duccio_maesta1021.jpg
...and this is good stereo:
http://en.wikipedia.org/wiki/File:Entrega_de_las_llaves_a_San_Pedro_(Perugino).jpg

a double blind test only gives a positive result: If there is a difference, it means that what was tested is indeed audible. But a negative test only says that with this material, this equipment, this room, these subjects did not hear a difference today. but that's it. With some other people/material/equipment/room there might be an audible difference. You can't prove "no audible difference".

Typical audiophool excuse. Double blind tests are good enough for medicines. You know, the stuff you trust your LIFE with.
If, using a large enough sample, there is no difference, or the $10000 amp actually sounds worse than the $100 one, then I doubt there's reason to be quoting "what ifs".

#2: Real life situations very seldom are blind. And the hearing sensation is real, even if it might only partly come from movement of air molecules. We know (as a proven, scientific facts) that color TVs don't sound as loud as B&W TVs but they have a better sound; black speakers sound better than red ones; big speakers have better bass etc.

Lol. When I pay for audio equipment, I am interested in sound quality, not in how its looks (and price) will affect my subjective perception of the sound. If hi-fi stuff was marketed honestly, like saying "this black mahogany supertextured finish and the impressive size of the unit will be a highlight of your living room", I'd say it's okay. But instead they spout shit like "our scientifically engineered mahogany finish absorbs subspace particle resonations and evens out the warp field for an optimal listening experience."
Are you by any chance involved in selling this snake oil stuff? You sound awfully apologetic.

- Measurements: I'm an engineer, so I believe in measurements. I also believe that we don't have enough knowledge about how humans hear to know what to measure. Besides, I haven't yet seen any audio equipment with different designs that measure equally(!).

There are lots of honest companies who have put in years of research into finding out exactly what to measure. Dolby, once again... And we have practical and really cool stuff to thank that research, for example mp3 compression.
I doubt the ones selling the magical $10000 amps do the science.
Plus, for an engineer, you're making far too many excuses not to trust measurements. I'm sensing an ulterior (financial?) motive here.

which I still believe should be inaudible by a wide margin. Still, the press (sometimes in comparison tests) gave comments about the other products high-end, like "Nothing is missing, but it is a bit smoother than X", far too many for me to believe those were random guesses.

Of course it's not random. The press is trying to "impress" its sponsors. I'd like to see the same result in double blind tests. (That said, it's not impossible that such a minute difference is actually audible. That said, we're talking about a pretty specific, measurable difference.)

[edavid]

We know that when somebody loses one of their senses the others become far more acute as a way to compensate for the loss. In the case of somebody who loses their sight, their sense of hearing becomes markedly improved.

This is completely wrong.  Just another myth.

[scientist]

We know that when somebody loses one of their senses the others become far more acute as a way to compensate for the loss. In the case of somebody who loses their sight, their sense of hearing becomes markedly improved.

Seems to be markedly improved, because they have nothing to compare it against and their memory is extremely fallible.

[Sigmoid]

Seems to be markedly improved, because they have nothing to compare it against and their memory is extremely fallible.

There's a bit more to it than that. For one, the brain contains a mechanism for blocking out and filtering input based on attention. (I mean, actually closing the neural pathways.)
With a sense dropped out, more attention is directed to all other senses. Also, there's the thing about neuroplasticity, with areas of the brain repurposing themselves. For example research shows that many blind people use their visual cortex to process Braille writing.

That said, it's true that there's no evidence of the hearing itself (in terms of frequency sensitivity, sensory limits, etc.) improving. It's just that if someone only has their hearing to rely on, there's a lot more processing happening on it in the brain.

[Marco]

I was demo'ing some audio gear (including spkrs) at a show and the spkrs were from someone else.  he told me that the red/black posts may not be right.  I connected it and used the spkrs anyway.

one guy came by and said he thought the absolute polarity was wrong.  I don't believe he was there when the spkr owner explained that to me.

You're destroying the base by connecting them in anti-phase, I'm sure a lot of people won't notice but it's not something you need golden ears to recognize.

[Bassman59]

I was demo'ing some audio gear (including spkrs) at a show and the spkrs were from someone else.  he told me that the red/black posts may not be right.  I connected it and used the spkrs anyway.

one guy came by and said he thought the absolute polarity was wrong.  I don't believe he was there when the spkr owner explained that to me.

You're destroying the base (sic) by connecting them in anti-phase, I'm sure a lot of people won't notice but it's not something you need golden ears to recognize.

The effects of one speaker reverse polarity from the other is obvious if you know what you're listening for.

Here's a good one. I am a live sound mixer, and I had a gig in a new venue where they did up a decent install with some older but perfectly functional gear. The mains top boxes were EAW KF650s, two a side, and they were flown with the two boxes in a pair butted up against each other. If you know anything about these boxes, you know that's a recipe for serious comb filtering, because the horns are too close together at that angle.

I had no way to fix this (basically you spread the boxes so there's a 6" or so gap between them) but after soundcheck I grabbed the house engineer (young girl, actually interested in learning) and the promoter, and played some tunes through the rig and just had them walk slowly in front of the boxes from side to side. I didn't tell them to do anything other than listen.

Both immediately heard the problem and asked how to solve it.

These sorts of things, the time-domain interference issues (coupling between boxes, interference between a box and a nearby wall, etc), as well as the simple polarity flips, are easily recognized once you're exposed to them and the problem is explained.

[ampdoctor]

Huh? I don't get what you're saying. First you say there's a lot of directional info we perceive, and then say our hearing is more like mono? Could you elaborate?

Anyway, good stereo is a LOT MORE than "left side of the room goes in the left channel and right side of the room goes in the right".
This is equivalent to "left side of the room goes in the left channel and right side of the room goes in the right":
http://en.wikipedia.org/wiki/File:Duccio_maesta1021.jpg
...and this is good stereo:
http://en.wikipedia.org/wiki/File:Entrega_de_las_llaves_a_San_Pedro_(Perugino).jpg

It's exactly what I said. High frequency content tends to be rather beamy and directional. Lows tend to spread out all over the place so you know they're there but it's hard to pinpoint the exact source. And when sounds get really loud, you can turn your head any direction and it has very little effect on whether you perceive it as coming more from the left or the right. This is also true for distant sounds. While the distribution of sound may be somewhat more dominant to the left or right, the information is still received on both sides.

For example, at this very moment, I can hear the TV playing in the other room. If I cover one ear I can still hear everything with the same clarity, though at a slightly diminished volume. So maybe it comes down to what your personal idea of mono vs stereo happens to be. My definition of stereo would generally be something along the lines of "two point sources of audio that are phased and amplified as necessary to allow the brain to construct a sense of 3 dimensional space."

With recorded sound, off the top of my head you've got natural stereo, panoramic stereo, dolby stereo, surround sound, dual channel high fidelity, pan pot stereo, pseudo stereo monophonic. I know there a a ton of other techniques studios use that I just don't know the names of.  Often times when music is recorded and mastered different instruments are given dedicated channels and usually vocals and percussion are recorded mono or equally left and right. In the recording studio there are no hard and fast rules for doing anything. Depending on the skills of the recording and mastering engineers mono or stereo recordings can be quite unnatural sounding. To get a good idea of how good mono CAN sound, dig up a copy of some of the original Beatles albums. Those were all done in what I believe was pan pot mono and remastered later into stereo. The difference is mind blowing! That's also why I said that's a completely different conversation.