Speaker measurements: assistance needed

Wildcat

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Just a quick request for any fellow SMAC members who may also be DIYers: is anyone here equipped to help test Thiele-Small parameters on a pair of woofers I bought recently? These are pulled from the Martin Logan Dynamo 500, and because the system is still in production, ML cannot provide parameters for it. I've already searched a bit for the specs, but of course, nobody else has them either.

I have a couple of uses in mind for them, but won't get far until I can grab the measurements. I can do some of them here at home (even using my laptop as a frequency generator), but I'm hung up on the required enclosure to measure Vas. There is a method using 20 grams of mass added to the cone (via Blue Tack, or whatever it's called), but it is supposedly not as reliable. As a makeshift move, I can fill an existing enclosure enough to get close to the ideal testing volume, but figured someone may already have a box rigged up to test woofers with.

If anyone has any insight or info, I'd appreciate it! Thanks for reading!
 
IMO, the added mass method works well enough, and a test enclosure isn't terribly fussy on volume. If you put your location in your profile, there might be somebody close to you that can help.
 
I know a rule of thumb is to have a text box be approximately the cube of the driver's nominal diameter, which would mean a 10" woofer would have something near a 1000 cubic inch box. One thought I had was to use some solid, non-porous objects to take up volume in the speaker cabinet to temporarily reduce its volume, mounting the woofer inverted while I run the measurements. It's a bit of work though, as I'd have to remove all the insulation (which I believe is glued in). I can see a problem if the box is way too large--the woofer is less "loaded".

I may use the mass method just to get me started on this project. Given the end result though, I'm trying to be as accurate as I can.
 
Heck, everywhere in Michigan is near a lake☺ Are you using Woofer Tester? I have that program and use it all the time. You are welcome to bring your woofer over here if you want. PM me if you want to. D.
 
Heck, everywhere in Michigan is near a lake☺ Are you using Woofer Tester? I have that program and use it all the time. You are welcome to bring your woofer over here if you want. PM me if you want to. D.

My test equipment is somewhat limited (nothing other than software which can handle most of my basic needs), but do have a good multimeter on hand.

Once I'm done with this crazy semester in a few weeks, I'll have time to work on this project. Thanks for the offer--I may just take you up on that! :thmbsp:

I'm only about a mile from Lake St. Clair. And a mile and a half from the Nautical Mile.
 
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