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Hey guys, I was wondering if anyone has had experience with this measurement system?
http://www.partsexpress.com/pe/psho...tnumber=390-804

It'd be interesting to measure the T/S parameters in some of my store bought speakers and to also measure my DIY speakers to see how close they measure to those provided by their manufacturers at such a low cost.
 

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I know someone who has it and used it.. and you'd be surprised at how different the ACTUAL T/S parameters are compared to the published specs.. even among the same driver, you can get some surprising swings, even on high quality drivers.

JCD
 

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Do you have the time and inclination to post your results here? Even if your speakers aren't the "common" units discussed here, the difference in factory specs vs real specs is very important for DIYers. The amount of difference between factory and real specs can mean a box which has to be bigger or smaller to achieve the best performance . . . . or . . . . the differences can mean the tuning port or tube is too short or too long. And then measuring for crossover frequencies can be affected too to the point that a DIYer just gives up in frustration because the crossover point and component values don't produce the desired result. Please share with us if you can.
 

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Discussion Starter #5
Do you have the time and inclination to post your results here? Even if your speakers aren't the "common" units discussed here, the difference in factory specs vs real specs is very important for DIYers.
Man, I couldn't agree more with this statement...
 

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It wasn't me that did it, but here is a Link.

JCD
Oh ****! I mean oh goody. That poster "Irritateguy" has a lot to offer in regards to speaker measurements and other info. Anyone here willing to invite him over to this site so we can pick his brain and steal his ideas? :whistling:
 

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I woulda if I coulda.. I've actually met him and listened to his old rig (which was pretty amazing).

That being said, he likes only being on one forum where he doesn't have to explain and defend who he is, etc.

JCD
 

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OK, I guess that's all we can ask of you.
We can all appreciate his feelings toward those who would demean him. We sure do read enough of that "stuff" on here.
 

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I've got the wt2 version and was able to measure one of my subs before the wt2 quit working. One of the largest variations from manufacturers specs was the Fs, manufacturers claimed 16Hz the wt2 measured it as 29Hz.
Here's the comparison:

Cadence CW18-951-4 18" HEAVY WEIGHT SUB WOOFER

Manufacturer vs wt2

Fs 16.00 ----- 29.11
Vas 11.73----- 10.49
Qes 00.53 ----- 00.657
Qms 9.01 ----- 4.90
Qts 0.50 ----- 0.579
Re 3.69 ----- 4.053

These T/S differences translated into closed box enclosure size, according to WinISD, would make the manufacturers box about 12 cubic feet versus the wt2 ..... 23 cubic feet!
I made a box 7.1 cubic feet to fit a TC sounds speaker but tried the Cadence in it first. I was about to measure the in-box parameters and accidentally hit the go loud control and blew up the speaker.
I'm currently working on my emotions and another speaker/amp project.
 

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Discussion Starter #11
Island, Wow.... I may never model again using published T/S parameters!

So far I've either been really lucky or haven't noticed how off spec the drivers in my DIY projects are..
 

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Island - was that WT2 test of the Cadence driver after substantial break-in?
The Cadence was over 10 years old. It had been my first real attempt at a subwoofer. That speaker had been in an infinite baffle, bass reflex, and a closed box. It seemed to work well in any application but of course at that time I had no way of measuring it's frequency response or T/S parameters. I bought it strictly because of it's advertised T/S parameters.
I started questioning the parameters when my son recently bought a very similar looking 18" speaker from Eminence. Same cone material same spider same magnet same basket same voice coil diameter same measured Re. The only difference seemed to be the surround. The Cadence had a foam surround vs the Eminence had a pleated cloth surround.
The Eminence had similar advertised parameters to my measurements with the wt2 tester.
My guess is Cadence got into the T/S parameter advertising game early on as the car stereo and DIYer market started to heat up. I don't think my Cadence ever had the advertised specs and as a result my designed boxes, although functional in a way, were never as accurate or correct as they could have been. Now that the speaker has been blown up I'll never be able to find out just how good or bad it really was.
 

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But now I've recently purchased a TC Sounds speaker and the wt2 unit won't calibrate correctly and the mesurements of the Tc Sound unit don't match the manufacturers specs either.
My problem might be the wt2 unit and not my speakers.
I'm workin on it . . . . . :foottap:
 

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Island, Wow.... I may never model again using published T/S parameters!

So far I've either been really lucky or haven't noticed how off spec the drivers in my DIY projects are..
Hey Exocer
take heart ,
All speakers make some kind of noise when they are hooked up to an amp. They even sound better when you put them in a box whether or not the box is the best size or right design. And then how good are our ears? Can we really identify the difference between speaker box combinations when one unit is down 3db @ 20Hz vs another speaker box that is down 6db @ 20Hz?
We HAVE to measure and model using whatever specs we can find. We HAVE to build according to the software program's results. What else IS there for us DIYers?
I know myself I've come a long way from using cardboard boxes and 5 inch paper coned 5 watt radio speakers through building Karlson enclosures and huge bass reflex boxes and more recently accoustic suspension boxes (stuffed closed boxes) with 10, 12, 15, and 18" speakers all in an attempt to get to that "right" sound of the percusive bass drum, the string bass, the bass guitar, the sound of slamming doors, explosions, pounding whirling helicopter blades, an F-14 Tomcat fighter, the deep dull thud of dinosaurs walking (we've all experienced a real dinosaur in our lives so we KNOW what that sound is like), our mother-in law passing gas during her first use of the bathroom in the morning, and on and on and on.
With todays 2500 watt capable speakers and amps that can deliver twice or even three times that much power, we're sure to find subsonic, super low Hz nirvana soon. Keep reading these forums, the know-how the answer the solutions, they could be in the next thread. LOL
Phil
 
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