Woofer parameter tester

[djjdnap 78]

http://www.partsexpress.com/pe/pshowdetl.c...tnumber=390-804

[audio-neon 34]

One of my friends has it and when I asked him about it he replied with:

I like it, haven't really used it much though. I bought it to find out the Fs of the subs so I could build my comp enclosure so I don't really use it anymore. I check the Fs on occasion, but thats about it. Once I start building some more I'll use it more. I was talking to some people at a drags 3X show and they had a program that was pretty close to it, they said PartsExpress. com had actually ripped off that program from them. Apparently Parts Express only used a small portion of it and it only gives you 1/4 of the info you really need to build the right enclosures. Partsexpress charges $99 for this program and the real one was like $250. You can check out the real one at www. woofertester. com

[Robert_J 0]

I have it. I just picked up a 15ft USB extension cable so I don't have to sit an 18" sub on my desk. I also have to work on finding the Vas which is a little more difficult than the other parameters.

-Robert

[johnecon2001 82]

So it does work then? Fantastic idea for any professional box builders to get one, seeing how it's only $99.

[Aaron Clinton 2,372]

I was thinking about getting one. Will look forward to see what Robert says.

[helotaxi 46]

I was planning to order one if for no other reason than to play with it. Vas is fairly to simple to test with something like that IIRC. Simply a matter of loading it into a known enclosure and seeing how the parameters shift from the free-air parameters.

[DevilDriver 28]

The WT3 is a fine option. The real advantage to it is the quickness with which you can take Thiele/Small measurements.

http://audiojunkies.com/blog/1016/wt3-woof...ew-dayton-audio

[Robert_J 0]

I was planning to order one if for no other reason than to play with it. Vas is fairly to simple to test with something like that IIRC. Simply a matter of loading it into a known enclosure and seeing how the parameters shift from the free-air parameters.

But I don't have enclosures for every driver ranging from 3" to 18". I've been trying to find information on using the added mass method. I think it would be easier but I need a known mass as well as a method of attaching it to the cone. I don't want to leave a mark on the cone either.

I just tested my TC Sounds/SVS Ultra/Audiomobile Mass driver. Interesting results:

Re 3.547 ohms

Fs 25.57 hz

Qts 1.145 (much higher than expected)

Qes 1.383 (much higher than expected)

Qms 6.656

Le 1.092

Mms (missing)

Vas (missing)

Once I run my Vas test, the Mms should be filled in as well.

Also, the parameters change depending on the orientation of the driver. The specs above were taken with the driver sitting cone up on the floor. Here they are with the driver horizontal on the floor.

Re 3.428 ohms

Fs 26.24 hz

Qts 1.152

Qes 1.343

Qms 8.109

Le 1.092

I need to find the preferred driver orientation and stick to it.

All in all, I'm happy with the tool. As with most precision measuring devices, there is a learning curve and I am at the bottom of it. But with the number of drivers that I don't have info for and the recones that I have been doing, it will at least give me an appoximation of the T/S parameters.

-Robert

[helotaxi 46]

Horizontal should be more consistent because the weight of the cone won't cause the suspension to sag. For the delta-mass method, once you have a known wieght to work with, stick it to the cone with a control piece of Blu-Tac (i.e. weigh the Blu-Tac and keep the same piece for future use).