Deep Stereo

[k brown]

an attempt had been made to put FOUR channels onto vinyl discs, using the regular FM radio-carrier principle to put two channels on each groove wall. That's gonna work innit ...

The hew-larity of that system (from the geniuses at RCA) was that the grooves of the ultra-high frequency carrier signal were so teensy that after a few plays with with anything other than an extremely sophisticated and expensive tonearm and exactly the right-shaped stylus, it would be rubbed out forever - goodbye quad.

[trogluddite]

I got so immersed in listening [...] that I became convinced that my body was in an entirely different position than it really was. Freaked me out, big time.

Then you have some insight into some of the autistic perceptions that I've spoken of in other posts. That's just the kind of "hyper-focus" that's an everyday involuntary experience for many of us. The human mind's feeling of embodiment stems mostly from the sense known as proprioception, which can either just be a bit wonky like mine, or becomes "locked out" by hyper-focus. Hence my scruffy beard - if I focus on using a mirror for shaving, my brain gets confused which of the "bodies" it's controlling (familiarity since infancy means that I usually find it more amusing than freaky!) I write all of my best code in such a hyper-focused state, though I'm inclined to get rather ratty with people who dare to snap me out of it!

There are very few autistic sensory oddities that can't be experienced by anybody if the conditions are right - you've got me wondering how FS might be used to create some of these conditions, in order to give people insights like you've had which are so often hard to put into words.

But what I did find was great stereo imaging. I eventually realised this was down to the fact that they had concentric tweeter cones.

A friend of mine years ago had a pair of the old Tannoy dual-concentric monitors, and I found the same listening to those - they weren't the highest-fidelity monitors that I've ever heard, but the imaging was pin-sharp and the "sweet-spot" much broader, especially in the vertical dimension.

[k brown]

"Hyper-focus" must also be related to the phenomenon many artists (I'm a landscape painter) all too-occasionally experience, of the sensation that someone else is doing the painting/moving your hands and you're just watching. Sometimes you hear writers talk of the pen doing the writing.

The notion of using FS to create something that allows others to experience a simulation of alternate 'states of attention' - fascinating idea! You're probably aware of the VR software someone developed that allows 'normal' people to experience schizophrenia.

@Spogg - Several small companies continue to develop HQ small-diameter full-range drivers - most famously the 'Jordon module', no longer made I think or the company's morphed into something else. They made a 2-inch !! driver that was full range down to something like 60 or 70 Hz. It's a very passionate subset of the audiophile world, just not in general consumer products. The single-driver spherical enclosure units I mentioned in the original post used 3" full range drivers made by Audax. The biggest single factor limiting most speaker imaging is time delay between the multiple drivers and phase-smearing by most passive cross-overs. One of the reasons the two-way system I had could still do the Transaural bit was that they had active line-level cross-overs before the power amp (bi-amping). The cross-overs were almost phase-perfect 24dB/oct units of the Linkwitz-Reily type. The power amps in that system were hilarious - car stereo power amps in cardboard boxes

[Spogg]

I didn’t know about that strain of audiophile stuff Kevin, so thanks for that.

I did know about active cross-overs and bi-amping, and I’m sure that’s much better than passive systems.
However, there will still be some phase issues due to different voice coils and speaker placement within a multi-speaker enclosure. Even if you locate the tweeter in the centre of the bass/midrange speaker, they won’t be driven by the same coil in the exact same location. For stereo imaging I still think the dual concentric system is hard to beat.

Cheers

Spogg

[trogluddite]

"Hyper-focus" must also be related to the phenomenon many artists (I'm a landscape painter) all too-occasionally experience, of the sensation that someone else is doing the painting/moving your hands and you're just watching. Sometimes you hear writers talk of the pen doing the writing.

Very much so, I believe; I get the same feeling when I'm playing a musical instrument very often (I was also a painter of abstracts at one time, too, though haven't picked up a brush in a very long time). I think also probably related to the mental states of meditation. I struggle to quieten my mind enough to meditate conventionally, but I'm convinced that this kind of hyper-focus can be a form of "active meditation" - even when creativity isn't explicitly a component of it, I always find it extremely therapeutic.

[wlangfor@uoguelph.ca]

Have you guys tried the mighty dwarf speakers? Heard good things about them. Interesting tech. Seems it would be good tech for removing phase in many ways, especially for Dolby.

Speaker Transaural is actually more restrictive (nothing comes free ); if you move your head the cross-talk cancellation is destroyed and you're back to 'nice sound of speakers all around'. At least with headphones the illusion of what the dummy head recorded remains - it just doesn't change to reflect your changed head position. That's the biggest downside of this - you have sit in a small sweet spot and NOT MOVE. Personally I've never been bothered by it because what I'm hearing is so captivating I don't want to move. I've always been one of those motionless, intensive listeners. I actually had essentially an 'out-of-body' experience from this once. I got so immersed in listening to the Apocalypse Now soundtrack (an unusually three-dimensional recording for a film sountrack (http://designingsound.org/2009/10/07/wa ... orldizing/) that I became convinced that my body was in an entirely different position than it really was. Freaked me out, big time. This was when I was in film school, and my roomates/classmates so identified me with this 'instensive listening' habit that they spoofed it in a film project by shooting me listening motionless to music, then dissolving to a shot of me covered in fake cobwebs.

[k brown]

That's pretty much the opposite of what you'd want for what we're talking about - you want something close to a pinpoint phase coherent source, not something that turns an entire surface into a transducer. It's why the system I had that produced the most complete cross-talk cancellation used 3" diameter full-range drivers.

[wlangfor@uoguelph.ca]

That's pretty much the opposite of what you'd want for what we're talking about - you want something close to a pinpoint phase coherent source, not something that turns an entire surface into a transducer. It's why the system I had that produced the most complete cross-talk cancellation used 3" diameter full-range drivers.

Yeah, I had followed; but that I just meant so that there would be more range of motion and the effect would still be audible. Like in the case of a living room and at a party for instance. Maybe if a large room, that'd be the best style of center perhaps from the floor?

[k brown]

But the effect wouldn't be audible because it relies on very specific time delays between the L and R speakers and the listeners two ears - this can only be achieved by a specific placement of point sources. In the case of the system described, the L and R point sources must be 110 to 115 degrees apart relative to the listener, and the L/C/R speakers all the exact same distance from the listener - this can't be achieved by sources as large as a wall.