directional speakers

@audiokinesis I believe that you are correct.  Here is what the Theoretica web site says:

BACCH® 3D Sound will greatly enhance the spatial fidelity of sound reproduction through any loudspeakers. Loudspeakers that have high sound directivity² will give the best and most accurate 3D imaging in a highly refelctive room with little or no sound treatment, as room reflections, which degrade imaging, are minimized by such loudspeakers.

However, even loudspeakers with low directivity (i.e. omni-directional loudspeakers) will give a spectacularly spatial soundstage with BACCH® 3D Sound in a typical listening room. As the importance of room reflections is decreased (by increasing the ratio of directed to eflected sound through room treatment and/or higher-directivity speakers and/or nearfield listening) the image’s depth and 3D imaging approach the depth and spatial characteristics of the original sound field.

An ongoing investigation of speaker directivity at Princeton University's 3D3A Lab, has shown that dipole speaker designs, electrostatic speakers, as well as speakers with horns and waveguides offer significant advantages in 3D imaging with BACCH® 3D Sound in highly reflective rooms, as they increase the ratio of direct to reflected sound. Abating early room reflections with physical room treatment (i.e. using sound absorbers on sound-reflective surfaces) in a listening room is always beneficial to any audiophile-grade sound system. For BACCH® 3D Sound the effect of sound treatment is equivalent to using loudspeakers with high directivity, or listening in the nearfield. The more directive the loudspeakers are, the less sound treatment is needed for BACCH® 3D Sound to produce a full and accurate 3D sound image.

Therefore, in a reflective untreated listening room, directive loudspeakers are more desirable. In a well treated listening room with sound-absorbing surfaces, any loudspeakers, even omnidirectional ones, will produce an excellent 3D image.²

Budget is in the neighborhood of $5000; used is fine with me.  The speakers will be placed in front of bookshelves filled with books.  I could place the speakers 18" to 24" from the wall.

I rescind those recommendations that I gave. I don’t think they are as directional that you are looking for!

@treepmeyer posted, quoting from Theoretica’s website:

"An ongoing investigation of speaker directivity at Princeton University’s 3D3A Lab, has shown that dipole speaker designs, electrostatic speakers, as well as speakers with horns and waveguides offer significant advantages in 3D imaging with BACCH® 3D Sound in highly reflective rooms..."

Very interesting. These are pretty much the same conclusions I arrived at in my own explorations of loudspeaker design and room interaction (for unprocessed two-channel stereo). I like some of the attributes of dipoles and some of the attributes of horn/waveguide type speakers.

Duke

Well, that’s a lot of work for BAACH. :D

It’s well known that the more reflective a room the more treatment is needed to achieve the same level of satisfaction in detail. That’s not at all new or outside of prior work in acoustics.

In a modestly treated room, the Fritz with ring radiators do pretty well, but they benefit from some treatment.

Alternatively, along the same lines of thinking, if you can put the speakers well out into the room, as well as the listening area, you achieve the same goals.