Phase V

Current plans are forming around the AC-250F1, an AC-130F1 or MkII, probably the latter (I like the idea of using carbon fiber somewhere) and Hiquphon OW1. The two driver idea will have to wait. Some testing of the implications of the phase change created with any second order or higher filters suggest using only first order. I am assuming the trade-off is with harmonic distortion when significant signal gets to the drivers outside of their ideal operating range. This remains, as they say, an empirical question.  What bothered me was the real mess second order filters seem to make of a square wave.

Above is the simulated result of passing a square wave though the second order crossover designed around the AC-250, AC130 and OW1. Speaker Workshop generates the phase shift data in the total frequency simulation. Using these, I simulated a square wave from odd harmonics, and then applied the phase shifts from the Speaker Workshop output which I had dumped to a file. This (above) was the result and it looks terrible - nothing like a square wave.

This, by way of comparison, is the simulated for the first order crossover I designed for the same drivers. While obviously not square, it seems much better than the signal passed by the second order network.

If the rendition of detail has a lot to do with the accurate reproduction of transients, then the first order network should do much better at this than the second order.

My current plan is to build the speakers (when the wretched drivers get here in March or April) and two pairs of cross overs, one first order, the other second order, and see how they sound.