I decided to go up one volt (rms) at a time on my little drivers. It took over one hour, but they held up very well, indeed.
I don't know if I had mentioned, before, but part of the reasoning behind this design is driver excursion control, which is often a weak link in a diaphragm type speaker. I was able to increase the power handling in two little thirty five watt drivers to over two hundred fifty for the pair. I actually put thirty three volts (across four ohms, two hundred seventy watts) into them for almost ten minutes, before they became overheated and failed.
I guess the reason this is so exciting to me is that these drivers were never designed to be compression drivers. These were actually fairly cheap car speakers, but this enclosure has gotten quite a bit of acoustical energy from a "poorly designed" driver.
"But, how do they sound, Dawg?"
Well, they weren't too bad, really. (Plus or minus three dB from forty eight Hertz to two hundred ninety Hertz, excellent for a six inch diaphragm) I only measured the response at the ten watt level and there was almost no non-linearity at that volume (roughly one hundred dB, which I would not call adequate for a true bass speaker), but this enclosure added four dB to the efficiency of the drivers. Of course a real horn would add eight to ten, but horns are notoriously non-linear, except for a narrow range where the pressure inside the horn is equal to the pressure inside the sealed chamber.
OK, enough about this test. My next move is to replace the drivers with new ones which I already have and goof around trying to get a lower frequency range out of them. I won't be worried about power handling anymore, just getting a lower, flatter response.
