Any enclosure ideas for the "new" JX92S? - Page 2 - diyAudio
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Old 29th February 2008, 02:34 PM   #11
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If you look up at post #6, you can see Brian's measurements out of the box, and Zaph's (apparently either belt _or_ suspenders technique ;-)) after whatever break-in he applied. Fs did go down, but Qts is higher.

Since I have a pair of Variovents from a prior stillborn project, I may use those in a .38 cu ft PE box, first without the ribbon, and then with. Thanks for the input, guys. - Pat
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Old 24th March 2008, 09:02 PM   #12
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My Jordan JX92S driver from the recent group buy as measured with WT3:

Fs 51.8 Hz
Qts 0.56
Qes 0.77
Qms 2.12
Re 5.2 Ohms
Le 0.17 mH
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Old 24th March 2008, 09:47 PM   #13
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Fairly close measurements for the three pairs from this batch, and all differ from the "official" specs. I know little enough, however, to still be baffled as to how the difference translates into differences in designs such as GM's MLTL, or optimum box size for the Griffin mini. - Pat
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Old 25th March 2008, 01:47 AM   #14
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While many will argue the nuances of T/S measurements, one measurement that is fairly straight forward is resistance. It seems that everyone who has measured this batch from the group buy is getting 5.2 ohms. Note that the manufactures spec says that Re is 4.5. This to me seems to imply that the voice coils have changed.

This is a big change in T/S and I suspect that just dropping them into those enclosures will result in less bass depth and perhaps a hump in the bass response.
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Old 25th March 2008, 04:07 PM   #15
GM is offline GM  United States
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Quote:
Originally posted by tubesguy

I know little enough, however, to still be baffled as to how the difference translates into differences in designs such as GM's MLTL, or optimum box size for the Griffin mini.

In both the 31" and 48" MLTLs, Zaph's specs show a bit more mid-bass 'bloom' with the attendant faster roll off to Fp typical of mildly under-damped alignments, so in theory need to be closer to a wall or corner to protect them down low and any BSC may need to be reduced.

Then again, since I used published specs and don't recall seeing any measured ones before now, for all I know nothing's changed.

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Old 25th March 2008, 04:25 PM   #16
sreten is offline sreten  United Kingdom
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Quote:
Originally posted by Colin
According to Ted (I asked last week when Brian's results were up, so the authority is pretty good here too), there is no 'new' JX92S - it hasn't changed and quality control has never been an issue.

The spec differences may be due to different measurement methods. Try the established specs first for enclosure design.

Ted tends to go for a belt and braces method on measurement, using traditional methods to verify what the computer measurements are telling him (ditto on enclosure and crossover design), so I'd be inclined to trust his results.
Hi,

Given Zaphs test results have verfied by others, they agree with good
manafacturers specifications and that he used two seperate methods
to come up with near identical results your attitude is hard to fathom.


Quote:
Yes, those really are the Thiele/Small parameters. I use the delta compliance method, which is far more accurate than the delta mass method. They are way off from the factory specs. I've also included the results from the Woofer Tester 3. It's an all-inclusive hardware solution to get woofer parameters. By all-inclusive, I effectively mean hard to screw up with a wiring error. The results are similar - a high Qts. I've posted both to show two completely different software packages coming to close agreement on specifications that are far, far off from the manufacturer's. Maybe that will help minimize the number of people saying "Gee, Zaph's T/S numbers are very different from Jordan's, whose do I beleive?"
You can lead a horse to water ......

/sreten.
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Old 25th March 2008, 07:12 PM   #17
Colin is offline Colin  United Kingdom
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Well, I wouldn't have a clue how to measure T/S and TJ has had 50 years experience, so it seems a reasonable attitude to take. Especially as Zaph doesn't even rate fullrangers generally. So, I'll leave the debate to the experts.
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Old 25th March 2008, 07:44 PM   #18
sreten is offline sreten  United Kingdom
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Quote:
Originally posted by Colin

Especially as Zaph doesn't even rate fullrangers generally.
???, what has that got to do with it ?, /sreten.
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Old 25th March 2008, 08:21 PM   #19
Henkjan is offline Henkjan  Netherlands
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Quote:
Originally posted by gmilitano
While many will argue the nuances of T/S measurements, one measurement that is fairly straight forward is resistance. It seems that everyone who has measured this batch from the group buy is getting 5.2 ohms. Note that the manufactures spec says that Re is 4.5. This to me seems to imply that the voice coils have changed.
be aware that most common resitance meters will not acurately measure anymore in this range (allthough a difference this large may be significant), I know mine doesn't
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Old 25th March 2008, 10:47 PM   #20
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Quote:
Originally posted by Henkjan
be aware that most common resitance meters will not acurately measure anymore in this range (allthough a difference this large may be significant), I know mine doesn't
I measured 5.2 ohms with Woofer Tester 3.
With a good multimeter, I measured 5.3 ohms.
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