Shocking 3D sound in 2 channel

12-31-13: Stringreen
Johnny53....it just might be your room.

Which one? I would say the beginning of this for me goes back to when I worked at a mid-fi/high end store in 1975, where the manager set up some Dahlquist DQ-10s with a pre-amp capable of depth layering. From then on, with 11 different sets of speakers in over a dozen different listening rooms driven by countless combinations of electronics on both coasts and in between, I have set up my system to get a strong center channel presence when on the source.

There are certain characteristics a speaker must have for this to happen, including fast transient response, good in-room power response without dramatic dips in the dispersion pattern, crossover design that keeps the waves pretty much in phase, etc. For example, phase-coherent speakers (e.g., Dahlquist, Thiel, Vandersteen) do this well, as do well-set-up planars. For dynamic speakers, a narrow front baffle helps.

Basically you need speakers that don't anchor the sound to themselves. Factors that call attention to the speakers include narrow dispersion, enclosure resonances, and wide baffles that smear the initial waves that come off the drivers. You also have to pay attention to how far the speakers are relative to the room and your listening position and also toe-in. Sometimes you need it, sometimes not.

The following provide tests, with which one may determine whether their system actually images, or reproduces a soundstage, as recorded. ie: On the Chesky sampler/test CD; David explains in detail, his position on the stage and distance from the mics, as he strikes a tambourine(Depth Test). The LEDR test tells what to expect, if your system performs well, before each segment. The Chesky CD contains a number of tests, in addition to the LEDR. (http://www.chesky.com/various-artists--jazz-sampler-amp-test-volume-1.html) (http://www.audiocheck.net/audiotests_ledr.php) BTW; The shape of your ears' pinnae is also a variable, regarding your ability to perceive images/locate sounds.

I have had 3D imaging with different six foot Magnepans since the 70's.

Room, amplification, source, positioning, and good recordings are essential.

I believe Panel speakers like Magneplanar and electrostatics work best at 3D.

If you do not get 3D, you do not have High End system, properly setup, in a decent room!

Buy Jim Smith's book "Get Better Sound".

Have not heard it too often in stores.

Yes, this happens in my system all the time. KEF Reference 203's and good music. I love to put the pre on "Stereo", have someone sit in the sweet spot and tell them to listen to the center channel... Then I tell them it's not on, that everything is coming from only the the 2 L/R front speakers. I had to disconnect the wires to the center channel on one occasion to prove it to an unbelieving friend.

Here’s an interesting example of audio geometry, courtesy of the album “Moving waves” by the Dutch band “Focus”.
If you have a copy of this album, tune in to the long track called “Eruption” (Side B of the LP). If you are using the CD, at counter reading 9 mins 18 secs.
(The panels in question are Martin Logan Vantages BTW).

Jan Akkerman’s guitar –
- Starts in the R channel, approx. 3 ft above the floor, centred within the panel.
- It slowly pans horizontally to centre stage where it pauses briefly.
- It then continues at this steady height to the L channel where it pauses again.
- Then, surprisingly, it climbs upwards to the very top of the panel (5ft) and pauses again.
- The guitar then pans at this new height of 5 ft to centre stage.
- It continues onwards to the R channel and pauses.
- Once there it slowly descends until it reaches its original start point.
- This completes a perfect rectangle, in the vertical axis, at the speaker plane.

Generally we are aware of a room’s tendency to height presentation but I don’t often hear elements quite as mathematically specific as this.
Once the mastering engineer adds a bit of reverb to an electric instrument the game changes.
The instrument leaves the confines of the speaker altogether and behaves pretty much like an acoustic instrument occupying its own space.
It helps when one is as easily amused as I am… ;)