Robert, Nice lab.
I agree?HiVi??is great value for the money. Your analysis of increased dome diameter impacts looks correct. I did a similar rudimentary analysis but I determined what is best by measuring. I did not do a complete power response analysis but rather just a listening window measurement. My DQ10 exhibits a very large amount of driver overlap. For example both the cone and dome range contribute equally over the range 760 hZ to 2.8 kHz. Additional the mid dome rolls off with asymmetrical crossover slopes at close to 18dB /octave slopes while the tweeter slope is closer to 6dB per octave. See the image below. the corrected measured repose of the HiVi dome on the baffle is quite close to the original dome mid. the system response also changed only very slightly. ?I do not critically listen off axis much at all. After careful measurements and listening I finally found the DQ10 sweet spot it is basically on the mid dome axis. This is the only axis where all the drivers will acoustically sum and the axis has a very narrow angle. At my listening position, about 9 ft away the sweet spot is only about 3" high and 3" wide. This equotes to a total angular variation of 1.6 degrees. Think almost head in a vice type of requirement.
If anyone is interested I can describe how to locate the sweet pot on your DQ10.
My woofer is now wired per the schematic and that is correct. It must be wired out of phase because and inductors, shift the phase 90 degrees. Since L1 is a low pass for the woofer and L2 is a high pass for the cone mid they shift in opposite directions for a total electrical phase shift of 180 degrees which is the same as reversing the leads (phase) o on of the drivers. Thus they must be wired out of phase electrically. You are correct that, when present, this affects the required phase of the driver next frequency band up or down, so it tricky to get them all playing together. ?I have confirmed that if you wire as shown on the latest schematic you will be correct .?
See below for a measured ACOUSTIC response of my system the may help clarify :
Just a couple of comments. Notice that the mid cone and dome operate at the same time over the range 760-2800Hz. Because fo the lateral displacement of those drivers I believe this and the very smooth summed response in this region is a big contributor to the DQ10 sound. Notice also that the woofer has large peak at 2.8kHz that affects the summed response. A similar issue occurs at 17kHz with the mid dome and the tweeter. I doubt that the later is audible for most of us over 60.
The last comment is the RED is measured at the listening position and all the other measurements are taken very near the individual drivers. this is necessary because the DQ10 has a hybrid series /parallel crossover networks so you can not easily measure one drive at time. You must get very close and use absorbers to try to best isolate individual drivers.?
Charlie Conger
