And further, wouldn't using the sealed box measuring technique
backwards yield a better understanding of how big the box really is? In
other words, I can simply calculate H x D x W, but that might not be the
effective volume of the box. The shift in the resonant freq. of the
woofer
in the box is perhaps more relevant.

No, because it does not account for the fact that the effective
mass load on the driver COULD change.

What? How?



My next question is this: Lets say the box measured above is
measure as a sealed box but intended to be ported. Now if I
have the ability to measure freq. vs. Z,

You'd have to to measure the T/S parameters anyway.


Of course I would! I'm not looking for any shortcuts here. I'm looking for
MORE things to measure.

The "exact" tuning of a reflex not only involve port length,
but it involves enclosure volume as well.

I understand the box and port together are a Helmholtz resonator; completely
independent of the woofer mounted in the box. But the woofer has to match
both the volume of the box and the tuning freq.



But, that being said, the answer is most definitely yes. It
is certainly quite valid to use the impedance curve to verify
proper alignment of a system, whether it's a sealed or vented
or passive radiator system. It's a method I use all the time:
simulation is used to generate a proedicted impedance curve,
how close does the final result match the design target? The
impedance curve not only tells you how close you got, it can
tell you why you missed.

How? What do you look for?



I have two completely different speaker design projects
going at the same time! I just got a delivery of 810 drivers
today! I will be putting together a website about both
projects soon and I will post it here.

Bah! There have been times when I had to verify that many
drivers a day, for a couple of weeks at a time. Great fun
it wasn't.


Well... I'm not working for someone else. Maybe that's why I love what I do!

James. )