Hi @CharlieM,
Is there anything special about the 12" width for the electronically segmented stators ? I read that you chose the segmented width (and cross-member height) to fit your pre-existing [beam slitter] frames. If you didn't already have pre-existing frames, would you have selected a different [wider] width ?
The 24.4" width of the Mylar C stock on the tensioning jig is a upper physical size constraint (considering wrapping the sides of the jig). More than 90 wires on the wire stretching jig is another constraint to contend with as well as the inner-tube diameter. I read another build thread that used an 18.5" width, but he had tearing difficulties with that width on the tensioning jig and the thread ran its course with no final published results.
The spreadsheet models adding 2 wires to each of the 15 x 6-wire groups (15 x 8-wire groups, total of 120 wires) will yield @ a 3-4dB increase in sensitivity, but I don't know if it would adversely affect other things such as imaging, off axis response, cross member stability, gap bottoming out, distortion, etc. This would still be narrower than the 18.5" build (2.73" wider baffle than stock, each of the 3 vertical sections would be 0.91" wider than stock).
Thanks much
We've all heard how inefficient ESLs are supposed to be, so when designing my very first ESL, I agonized over the panel dimensions, out of fear I would spend a ton of money and time and end up with a speaker that wouldn't play loud enough. I believe it was fellow member "Few" who told me not to worry about it, and he was right. My first speakers' 12 x 48 panels played plenty loud.
And when later upgrading to the wire panels, the 12" width worked out about right. My panels are already wider and taller than most commercial hybrid ESLs, and they can play to painful volume, so I saw no reason to make them larger in my latest speaker builds.
Sanders' ESL is a bit wider to offset the extra height of the TL bass box, but area-wise, it's not larger. Most commercial hybrids are proportionally about the same for a reason-- they've all learned over the years what works performance-wise and aesthetically, and there's no compelling reason to use a larger panel in a hybrid speaker. This is my view also.
If you want to increase the panel width as you described; dispersion would not suffer in the far field because it would be segmented accordingly. In a small room with forced near-field listening, dispersion/imaging would be perceived as less wide/less precise.
The span between diaphragm supports would still fall within the 100*d/s max rule, so no problem there. And the height of the wooden wire support slats could remain the same.
You had mentioned in an earlier communication that you might also increase the panel height. At some point, increasing area/capacitance would become prohibitive for the amp. The segmentation resistors would mitigate that, but I don't now how to calculate it or define a practical limit. Perhaps one of the more knowledgable members here can advise you on that.
Good luck with your project!
