Meyer’s configuration is interesting. I have tried a few experiment with this configuration; it’s difficult to get good horizontal pattern control without overlapping frequency bands and it’s easy to have issues associated with the cavity between the 10s and the horn flare … look carefully at what Meyer did.
This is what Adamson say about their new S10 (2 x 10” and horn)
“Low-mid frequency lobing is a common side-effect of traditional 2-way enclosures. To solve this problem, Adamson has introduced Controlled Summation Technology, which reduces the spacing between mid-frequency sources by outwardly splaying the drivers and using overlap control between mid-frequency and high frequency sources to suppress the interference normally associated with this type of design. Doing this also allows the high frequency sound chamber to retain its exit size, ensuring that it retains its superior directivity control”
Have a look at RCF’s HDL20 (2 x 10” and horn) horizontal directivity around 500-800Hz
http://www.rcf.it/c/document_library...DLFE-21711.pdf
… and also have a look at how db Technologies tried to solve the problem with their new VIO integrating the 10s output into the HF horn flare https://www.youtube.com/watch?v=eD0liUcfoVc
To keep the pattern control precise Martin’s MLA Compact design used separate horn for the MF and HF horns. To solve the associated horizontal directivity problems at the crossover point associated with parallax timing off-set, Martin used “VanishingPoint” high slop FIR filters … this is the approach I used in my 8” + horn design. It also used a horizontal phase plug on the 8” similar to Nexo’s Geo designs to improve vertical array behaviour.
“The GEO S-8 array element uses 8 inch cone woofers and 1 inch compression drivers, so we need to operate the woofer up to at least 1200 Hz. However, we can’t expect to get eight inch woofers closer than 10 inches on center. This means that they will be a full wavelength apart at 1300 Hz. Adjacent woofers will start to become separate sources at 325 Hz (1/4 wavelength spacing) and will be developing individual lobes at 625 Hz: far too low to cross over into the compression driver. A relatively simple phase plug on each cone, however, can narrow the dispersion in the coupling plane and widen it in the non-coupling plane, enabling adjacent woofers to couple effectively at much higher frequencies. The blue trace above is dispersion vs. frequency for an 8 inch cone woofer, with the patented GEO phase plug. Without the device (red trace) the pattern becomes too wide at crossover. With the device adjacent woofers can couple effectively at 2000 Hz which is a comfortable crossover frequency for a 1 inch compression driver.”
