Woofer Tester II - How accurate is it?

[richard c.]

Thank you for taking the time to explain how this works, and for the links. You have been very helpful.

I did have a couple drivers that required over 20 nickels, so I need to find another way, maybe. I think I'll try the small magnets and washers trick, IF I can get them away from the speakers magnetic circuit, and get an accurate weight.

I also wanted to test out some smaller drivers, too.

Richard C.

[duaneage]

I used clay carefully weighed on a .1 gram scale. I put the clay into small plastic bags and it does not bouncs nor stain the cone.

It does make me feel like a dope dealer to be weighing this stuff and packing it into little plastic bags.
I have the original woofer tester and while a bit dated (it uses DOS 6.22) It gets the job done. I also have calibrated boxes including a precise 1 cu ft test box that I use to double check the results manually. I found the old woofer tester to be within 10% of what I fund measuring manually, easily good enough for cabinet design.

Other enclsures I use are a coffee can for 5 and 6 inch drivers, other enclosures if the woofer fits, and so on.

One neat thing about the Woofer tester is you can use it to quickly determine the volume of a difficult enclosure, like the Control1 (122cu inches BTW) by checking the driver in free air and then in the box by covering the port. The rise in FS can be used to mathematically determine the internal volume.

This also worked on my pickup truck when I needed to know the convoluted volume of air available for the rear speakers.

[WTPRO]

Neat trick putting clay in the plastic bag trick

The new WT software has new option that compares the measured in box electricals (position and magnitude of peaks) to the simulator. When these are lined up, the simulators box volume and tuning will be quite close. The measured in air response is then usually quite close as well.

[boputnam]

Very cool, Keith - you keeping a watchful eye on us here and assisting the use of the Woofer Tester. Very cool indeed...

[WTPRO]

Thanks Bo

Following what is going on in the threads here at LH helps me keep on my toes too. If there is anything else I can help with let me know.

BTW, the offer still stands for anyone in the Boston area to get some free measurements made. After all, I only have so much stuff of my own laying around here to measure. What I would really like to do is model and then measure some of the more complex crossovers you guys are coming up with. Here is a link to what I am up to in that regard...

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

[boputnam]

Following what is going on in the threads here at LH helps me keep on my toes too.

Yea, it's kind of a free-for-all R&D shop. One has no idea of the varied configurations being worked on out here...

[4313B]

Yea, it's kind of a free-for-all R&D shop. One has no idea of the varied configurations being worked on out here...

Well... it's all that telling and then having to terminate those having been told thing... kind of like super secret spy shit. There are a few here that would have definitely racked up a small fleet during the Big One, you know, loose lips sink ships stuff...