AR 12" Data

[kkantor]

Yes, my mommy woundn't let me log on until I finished my homework. Well, I didn't actually FINISH it, but did get thought a number of important presentations/deadlines, which freed up a few hours.

Isn't that a nice spreadsheet? It's freeware, developed by a hobbyist. I've found it pretty accurate, if you populate it correctly.

http://www.danbbs.dk/~ko/ubmodel.htm

In terms of original drivers, Tom has some I hope to eventually test. Everything I am doing now is fairly speculative, in terms of how authentic the rebuilds are. As you can see, how one tests a driver greatly influences the results. And so, it is important to test an original by the same means as the rebuilds in order to assess how good the restoration methods are.

[kkantor]

Ignoring the insights that the Klippel gives into motor dynamics, the main things that stand out are (perhaps obviously) the ones that are the most drive level dependent. Qts and BL come to mind.

Traditional 2-terminal small-signal test methods are done at levels that produce very small cone displacement. It is my belief that this yields some underestimation of force factor, since magnetic and mechanical hysteresis lowers the back-EMF for such small displacements.

Clearly, the extent of this effect is very-much dependent on many variables. I'm still new at the Klippel, and don't have years of experience to relate its data to measured designs. However, it does seem to model magnetics parameters better than existing methods. Its main weaknesses seem to arise from the Klippel model's sensitivity to Xrest, and the difficulty in consistently establishing such. The advantage of the so-called "TS" (high-pass) model is its inherent insensitivity to DC behavior.

[Guest Bret]

> if you populate it correctly<

Houston, I hope we have a problem. I'm finding one of the drivers with a 20+ ohm DC impedance. The second one. . .#3 I think.

If that's right, please don't return that one to me. :-)

Bret

[Guest audioslave]

>> if you populate it correctly<

>

>Houston, I hope we have a problem. I'm finding one of the

>drivers with a 20+ ohm DC impedance. The second one. . .#3 I

>think.

>

>If that's right, please don't return that one to me. :-)

>

>Bret

I noticed this as well, but with driver #4. The data in the summary lists the Re fro friver #4 at 2.27 and 2.32.

http://www.aural.org/ar_hist/data/feb04_data/summary_02.xls

[Guest Bret]

>The data in the summary lists the Re fro friver #4 at 2.27 and 2.32.<

I noticed that as well. I can't turn-down an opportunity to give Ken a hard time ever since he called me "fussbudget" and suckered me with the re-touched jpg.

You know what I'm not understanding very well, though, is the relationship some of these numbers have to other driver parameters because several of them don't seem to make much sense. For instance, the liters of air that approximate the mechanical compliance. . . those numbers are all over the place and the high ones don't correspond to a high or low "other number" that I've been able to find yet.

The equivalent piston size is befuddling my brain, as well. But I'm not finished staring at them blankly yet.

I'm still looking and reading and building mental matrices.

Bret

[Guest Sean]

I'd love to view the new test results, but it is encoded in some format that i don't have a reader for. Anyone know where i can download the reader for this format? Sean