I have read a number of comments from listeners/reviewers who found the dispersion of the High-Velocity Folded Ribbon (HVFR) to be quite limited. CNET observed " I did note some treble softening when I stood up; so it appears that the tweeter's vertical dispersion is limited." A reader observed in response "Unfortunately, the detail just wasn't there - unless the ribbon in the center of the speaker was pointed straight at your ear. I must have looked absolutely silly in the listening room because I was stooping to get my ears in line with the speaker's center but it was amazing how much more detail was contained in about a 6" area of the room."

But, another reader responded " I stood and sat in every part of the room; no noticeable difference in the quality of the sound or the tweeter dispersion. "

I am concerned since I am planning a home theater with 3 tiers of seating with some 26 inches vertical distance between ear levels at the front and back rows. So, only one of those tiers could be well aligned with the LCR tweaters. What do measurements show about off-axis drop-off in response of the tweeters? Although it is known that limiting vertical dispersion of main speakers can improve the imaging, I would not want to trade this for big dips in high frequencies off axis.

Yes, the HVFR tweeter has a narrower dispersion pattern in the vertical plane, but it is only "narrower" than its spectacular horizontal, dispersion, which is nearly 180 degrees. It is no narrower than the typical sound-reinforcement type horn driver (also used in many home theaters). Most experts on acoustics agree that "controlled" vertical dispersion is actually "better" in a multi-channel HT setup.

In answer to your specific question, its all about distances. Nearfield you need the tweeter right on your ear axis, but, if you are far enough away from the speaker there is no issue. The person that stood up and heard no difference was probably far enough away from the speaker that the vertical sound field of the tweeter was large enough to cover the area from seating to standing. This is typically the case unless it is a VERY small room.

Thanks for clarifying the dispersion characteristics of the tweeter. You provide a nice estimate of the horizontal dispersion of nearly 180 degrees, Can you provide any quantitative indication of the vertical dispersion. What is the angle of the cone of vertical dispersion where the level of tweeter output is within half a decibel of the on-axis response for the full range of the tweeter?

More specifically, I might ask about my setup where the front row will be 20 to 24 inches below the screen and the speakers, which will be behind the screen. With the front row seats about 10 feet away from the screen, my ears will be about 10 degrees off-axis from the position of the tweeters (assuming that they are about 40 inches above the base of the speaker, and my ears are 40 inches above the floor. Do you have any measurements of the drop-off in tweeter level at 10 degrees off axis (10 feet away)?

That certainly sounds fine as you described... that's well within the listening window in my experience. I will have to ask if engineering has a vertical dispersion spec they can make available for us - if I get one I'll pass it on.

Since hearing is believing, why not go to your local dealer, stand back 10 feet from one of our models and move your head up and down to hear how large the window is going to be?