The first time I experienced invisible speakers with a soundstage far outside the speakers was at a friend's house while listening to Pink Floyd's "One of My Turns" on a pair of Martin Logan electrostatics. You had to sit in just the right spot to get the effect, but you could close your eyes and point to where the groupie was talking while walking around Pink's apartment. I went shopping for a new stereo after that experience, though Martin Logans were out of my budget (and required a metric ton of power) so I settled for an Adcom preamp and amp, a Rotel CD player, and a set of Vandersteen 2Ce's.
On my system which is fairly modest, and in a tiny room which is completely inappropriate until I move, I use the analogue productions Muddy Waters Folk Singer to bench soundstage, that recording is just insane in the way it fills the room. I really need to get the audiophiles guide for when I move as I intend to have a dedicated listening room and will really focus more on proper setup
Usually when people talk about an equilateral triangle in speaker set up they are actually talking about something different. With an actual equilateral triangle set up you'd have the same distance between the speakers as between each speaker and the listening position, but what people actually tend to tell you to do is to have the same distance between the speakers as between the middle of the front line that the speakers create and the listening position. That creates a longer distance between each speaker and the listener than it does between the two speakers, so clearly the triangle isn't equilateral.
Because his speaker placement is already in the ballpark from reading your book and because he's noting the wideness difference from track to track, what he's hearing is wholly due to recording he's listening to. Not every song is recorded/mixed/mastered to extend beyond the speakers and to the wall. Some music stays right there in between your speakers. It's not bad or wrong, it just is.
Knowing how to use phase, instead of level mixing, is how you make the recording, or the mastering come alive. Right and left panning should place a voice, then using phase delay make that sound tight or wide. In original Dolby Surround stereo encoding: everything in phase was played on left and right, everything in phase and the same tme was the center channel. Everything out of phase was sent to the 2 surrounding channels. Remeber, the Simpsons has been in Dolby Logic for almost 40 years. Phase, in stereo, is the best mastering tool. Now that we have 5 to 14 channels in modern home theater, we can phase any pair in the room, at any time. My house money Sonus Faber, McIntosh, Velodyne, Bryston 22ch system, mostly uses phasing over levels to place sound in a room.
That wide wide soundstage is what I normally see in rooms with Wilsons. They are toed in very aggressively. Wouldn't that create an extremely narrow ideal listening position? My issue with soundstage is that it is so great in some recordings and on others, the singer (usually) is way far behind the soundstage. Case in point Rush's Passage to Bangkok. With limitations on how close to each other I can get the speakers, I struggle with that.
If I tilt my head forward to face the floor the stereo image changes a lot, it is as though it becomes more 'intense'. I guess that it's all to do with the shape of ears and was very handy for our ancient hunting ancestors, not very convenient for enjoying your music though.
@ianbigsand7 yeah I get it. Try sitting in your listening position and cupping your hands behind your ears and then take them away. It's louder when cupped.
@4:24 "...confuses the sound, so your ear says 'I don't know what's going on'" Diffusion does not confuse your ears (or your brain). Rather, diffusion prevents your brain from being confused by echoes. Without diffusion: When echoes reach our ears, we are hearing the sound for the 2nd time (perhaps even a 3rd time). Our brains have trouble making sense of that. Diffusion addresses that, by having the echoes scattered in such a way, that the echoes reach our ears at random and radically different times, allowing our brains to ignore the incoherence of the sound delays. Also, diffusion sends the sound off into so many directions, that by the time the echoes reach our ears, the sound bounced around from one diffusion panel to another, reaching our ears at lower DB levels. Clap your hands, or whack something, and if the sound takes more than a moment to dissipate, then some diffusion panels would probably do wonders for your music's sound quality.
The only times I've ever heard a soundstage that's definitely wider than the speakers (with stereo) was using Q-Sound recordings and with Carver's Sonic Holography. Both have their problems and don't always work as well as you would like - like if you shift your listening position, or even just look at where you hear the sound coming from, the effect goes away and all you get is a blurry sound image.
I've always been intruiged by those tones that you hear, I don't even know how to explain it, but they seem to permeate everywhere with no perceptible source. I'm not sure what they're called or how they're produced but it'd be cool if someone utilized them in a track. Also, I wonder if releasing so many vids at once was intentional. 😂