Here is data from four waveguides I did which was inspired by Dr. Geddes.
http://www.diyaudio.com/forums/showpost.php?p=1887771&postcount=3194
Data are in 7.5 deg increments to 45deg rotated approximately around the acoustic center.
Top three are small waveguide about 23cm in diameter at the point where lip is tangent to the baffle. Bottom is a large elliptical waveguide. More details of each are burried in the thread if anyone wishes to research.
http://www.diyaudio.com/forums/showpost.php?p=1887771&postcount=3194
Data are in 7.5 deg increments to 45deg rotated approximately around the acoustic center.
Top three are small waveguide about 23cm in diameter at the point where lip is tangent to the baffle. Bottom is a large elliptical waveguide. More details of each are burried in the thread if anyone wishes to research.
A 12 inch waveguide can go lower, the limit may be the driver used. I have loaded them to 800 Hz using a BMS 4550 driver with the waveguide mounted in a small rectangular baffle like I did with the 24" waveguide. Not many 1" drivers can match the BMS 4550 low frequency output.
"I really like the big wide sound stage that three speakers can generate. Using a center speaker greatly improves the sound stage and widens the listening area considerably beyond the center seat."
With directivity down to 400 Hz it should work really well to toe them and cross the axes in front of the listening position.
Have you tried this?
These things are tempting but there's no way I could fit a center underneath my screen.
With directivity down to 400 Hz it should work really well to toe them and cross the axes in front of the listening position.
Have you tried this?
These things are tempting but there's no way I could fit a center underneath my screen.
Yes, the tops lift off the corner horns and I put the waveguides in place.
An externally hosted image should be here but it was not working when we last tested it.
My pre/pro has a choice of Dolby PLIIx, Neural THX, and DTS Neo:6.
I use Dolby PLIIx, panorama setting off, Dimension setting (rear level) to minimum, Center width = 1 (0-7 scale).
This paper explains how Dolby processing generates the center channel: Dolby PLII
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The speaker axes intersect in front of the seats. The left speaker is aimed at the right most seat and vise-versa (with the seats reclined a bit).
In my experience, no center speaker is a non-optimal set-up, and one that is barely acceptable only for a perfectly centered listener.
These coherent, constant directivity, point source waveguides from 400 Hz up create a very impressive sound stage.
Only if there is material specifically recorded for center channel. There are so many aspects of speakers that probably 99% did not even consider.
According to the previous discussions, 2in throat is not a good idea for upper treble directivity control.
Constant directivity is a big advantage as the direct sound and the reflected sound field in the room have the same tonal balance.
In addition, the single point source waveguide has the potential to reproduce an accurate acoustic waveform. The playback is accurate in both the time and frequency domains for sounds above 400 Hz where the human ear is very critical. The crossover into the woofer is also less critical.
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