waveguide speakers

What are the advantages/disadvantages of speakers with one driver loaded with a waveguide or both the tweeter and the mid/woofer loaded as such.

If I understand correctly distortion is lowered somewhat since less power is required, side wall reflections are reduced somewhat and the sweet spot is much larger.
Perhaps a place to start on waveguides:



My own speakers, Auto-tech's Mummy
MkII, are equipped
with a 12" so-called OSWG
waveguide(1" throat, fed by a compression driver) and a
12" mid/bass driver, incorporated into a heavily damped
fiberglass housing/enclosure, and they sound wonderful.
Here's a review of them, if it has any interest:


I've been a proponent of waveguide-based speakers for some
years now, starting with S.P. Technology/Aether Audio and
now the Polish-based Auto-tech speakers.

Feel free to ask away on specifics with regard to my
impressions on the sonic advantages of waveguide-based
speakers here mentioned.
You really should read the GedLee site. There is a ton of info there and Dr. Geddes is just brilliant.

I couldn't be happier with my GedLee Abbeys.
Also do some research on Audiokinesis speakers and their design principles. Dr. Geddes was a mentor to Duke LeJeune and both use waveguides in their designs.
Or if you are into DIY, check http//www.diysoundgroup.com
As indicated above, Geddes is an expert on this. I have heard that Genelec was the first to produce speakers with waveguides. I have Mackie HR624mkiis that have waveguides and love them - way better than the "audiophile" speakers I have owned in the past - BW 805s, Acoustat, Rogers, Advent. Undoubtedly the waveguide has something to do with it since it allows dispersion to be controlled, particularly in the crossover region - it flattens the power response to that of the direct response and reduces early reflections as well. See the Geddes website - BTW the Mackies have a similar measured response (flat on-axis and smooth even tapering in the highs off-axis even in the xover region) to the Geddes speakers.
The foam plug that Dr. Geddes uses is patented and a key part of the WG design. With over 21 patents, he has a clue!

Look at the bottom here. http://gedlee.com/Earl_resume.htm