Where to get Le for Altec woofers?

[Paul C.]

I can find most of the T/S parameters for Altecs, but no one seems to have Le... which is quite handy to know if you are designing a crossover.

Anyone know where to find this info? In particular, right now I need Le for 416's, 421-8LF, 515's.

Thanks!

[4313B]

Pick up a Woofer Tester II and measure them.

[moldyoldy]

Measurement is definitely the best method. T-S database says 0.001mh for almost all Altecs, which is obviously useless. With all the revisions the drivers you mentioned went through, voice coils changed nearly every time, though were mostly just materials upgrades to keep up with the current best of the day. Altec published the following for their last issue 515s, which is very close to what I've measured;

515-8G 0.58mh
515-16G 1.3mh
515-8GHP 0.68mh

[WTPRO]

Paul,

Just in case you might be inclined to be interested in a WT2, our driver modeling now goes beyond 'Le'. Basically Le is not constant with frequency, and there also happens to be a frequency variable resistive component. The WT2 both measures and models this. Follow the link below for an example.

Another WT2 unique feature is the ability to align its simulator with the final in-box impedance data. Basically this tells you the effective box size and tuning, but it also aligns the simulator. The curve at the bottom of this link shows just how well the two can line up.

Please also have a look at the rest of our web site and FAQ. We also do precision L-R-C measurements

http://www.woofertester.com/wt2boxbuild.htm

Hope this helps,
Best regards,
Keith Larson (WTPro)
Smith & Larson Audio

Notes: If anyone happens to be going at CES and would like to chat in person. Smith & Larson Audio we will be in booth 404 of the High Performance Audio Venue at the Venetian. We will be introducing the Woofer Tester Pro and Speaker Tester products.

[Paul C.]

Very interesting! Thank you!

[WTPRO]

Hi again Paul

Another FWIW, and another something we at S&L do, is measure TS parameters versus power level clean out to Xmax for the WT-Pro. Or WT2 base product will do this as well, but only up to its current drive limit of 3mA rms. For a lot of people this is more than enough, especially in light of the fact that you can often interpolate out another decade or so.

http://www.woofertester.com/cms_non_linearity.htm

Be sure to run through the FAQ and products pages... But be sure to check back at weeks end. The plan is to post a bunch of new pages as we head out to the show for maximum impact (WT-Pro, Speaker Tester and other products we are adding to our product line). I'd hate to spill the beans.

Best regards,
Keith Larson, WT-Pro

[WTPRO]

I should also mention,

If you can get your hands on an acurate Re and the impedance and phase at some frequency substantially higher than Fs you can calculate those Rem/Xem coefficients by hand. But then gain, you would want to also have a simulator that also understands them

Keith

[4313B]

Very nice Keith! I'm glad to see this happening. It was a long wait between WT and WT2 but it certainly looks like it was worth it.

[WTPRO]

Yeh, we did pack a lot more stuff into the WT2 compared to the WT1. Hopefully people will like our next products as well and the direction we are taking them. There are some pretty interesting things like being able to measure the acoustic distance to a driver to <1mm. Took some thunking to get that to work.

Keith