Hi Vi SD1.1 impedance

do you have one already, or are you just considering it for a design?

If you have it, I recommend tooling up to measure the impedance yourself. There can be quite a bit of variance among the same driver, so the one Zaph tested might be different than the one you get. Normally they are close, but it's always better to measure the one you have.

If you're just looking to virtually prototype a design then other people's measurements are the way to go. If Zaph is only off of the manuf. by 1 Ohm across the board, you can probably go with his and still design the crossover fine. Worst case, you will have to pad the tweeter slightly to compensate for the difference in efficiency. The shape of the impedance curve is what's most important (where it peaks and how it rises after the peak).

I hope this helps some.

Thanks for the reply Anthony. I don't have the driver. I am looking to prototype a design. Actually both graphs are quite different especially the peak at resonance on the manufacturer's graph.
HiVi: http://www.swanspeaker.com/product/htm/view.asp?id=26

This is all very confusing to me as I don't understand how they can be so different.

PS; I hope my link works. This is new to me. I also don't know how to save 2 links to the clipboard so I will post Zaph's link in a separate reply.

Zaph SD1.1: http://www.zaphaudio.com/tweetermishmash/compare.html

Acoustically, it looks like the two are pretty close. Zaph measured a larger amplitude peak at 15kHz.

It's tough to compare the impedance plots, since Zaphs is on such a small scale. he measured two peaks, but they are both close together. The manuf. one drops off at 400 Hz, so it's hard to compare them.