I've taken some measurements of one of my Infinity 1260ws and didn't really want to throw it in the HzHorn thread, even as gracious as BTH is. If you want the backstory, read posts 224 through 330 in that thread: http://www.avsforum.com/forum/155-diy-speakers-subs/1908857-hzhorn-8.html#post33235473 The TLDR would be: diy speaker guy realized that higher-inductance drivers, when measured, don't match the performance predicted in their models. The real issue is that most modeling apps like WinISD or even HornResp don't use a detailed inductance model. dsg found a way to get more accurate results by adjusting Re and Power, and LTD02 countered by suggesting we adjust Bl, Qes/Qts, and Le. Tweaking the TS params in this way gets modeled results much closer to the measured ones.
With that said, I've got measurements of an Infinity 1260w to share.
Here's my FR and Impedance sweeps and the calculated TS parameters. FR sweeps are close-mic'd at about 1/2" with a UMIK-1. Measured Qtc of the driver in the empty, sealed 38.6L box is .977.
Now, here's the WinISD models. All are in a 38.6L box, Qa=100, Ql=50.
The green line is Infinity's published TS parameters. Qtc of the driver in the enclosure was 0.7.
The blue line is based on my measured TS parameters. Qtc of 0.892.
The purple line is my measured parameters with BL adjusted to 14.5, Le to 6.5 mH, and letting WinISD recalculate Qes at .686 and Qts at .619. I manually entered all the mechanical parameters, i.e., Sd, Vas, Fs, Qms, Cms, Mms, so they wouldn't change. Modeled Qtc becomes 1.092.
And here's the purple line overlaid on the measured FR.
And for reference, a link to Infinity's published TS parameters: http://eu.infinitysystems.com/tl_fi.../Reference/Reference/1260w/REF1260W_PI_EN.pdf
Seems like this jives wih what dsg and LTD have been saying. I basically fiddled with BL and Le in WinISD until the peak of the curve as well as the points at 10 or 20 Hz, as well as 100 or 200 Hz, matched the curve of the measured FR. The higher end of the impedance curve (higher freq than what's posted above) and the Qtc aren't exactly on the money, but are much closer than they were.
When I get a chance I'll be measuring my HT18 D4s.
Comments? LTD or anyone else, did you have impedance-compensated TS params for any of the common drivers that you wanted to post?
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