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Thanks to Charles for lending me the driver to test. He actually leant me two of them so I could check consistency. Both drivers measured roughly the same...


Driver:
Vifa NE225W-04 8" Subwoofer
Vifa NE225W-04 8" Subwoofer 264-1104

Full report attached via PDF.

Pictures:

(Stock):







T/S and Impedance:

  • Re = 3.1334 ohms
  • Fs = 41.6843 Hz
  • Zmax = 35.5843 ohms
  • Qes = 0.4752
  • Qms = 4.9217
  • Qts = 0.4334
  • Le = 0.3102 mH (at 1 kHz)
  • Diam = 167.6400 mm ( 6.6000 in )
  • Sd =22072.1774 mm^2( 34.2119 in^2)
  • Vas = 24.2015 L ( 0.8547 ft^3)
  • BL = 8.4847 N/A
  • Mms = 41.6878 g
  • Cms = 349.6936 uM/N
  • Kms = 2859.6460 N/M
  • Rms = 2.2184 R mechanical
  • Efficiency = 0.3466 %
  • Sensitivity= 87.4161 dB @1W/1m
  • Sensitivity= 91.4869 dB @2.83Vrms/1m

Klippel Distortion Parameters:
  • X Bl @ Bl min=82% 3.8 mm
  • X C @ C min=75% 2.1 mm
Sample Klippel Data:











 

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Another driver that should test well, has all the goods but then it really isn't optimized at all. That or something went wrong during shipping. Those offsets are pretty severe.
 

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Nothing went wrong in shipping. I thought about possible manufacturing QC issues but this looks to be a design or tooling flaw becausae Erin was able to test two drivers with for this report and both performed similarly.

Vifa has some issues here. $250 drivers with 2.5mm Xmax is tough to swallow (albeit I picked these up for $85 per driver).

The motor seems to be well designed (from what I can tell). The offset is what is killing this thing. I wonder if there was some mistake in the basket design that caused the issue (motor positioned too far back). With the unique frame on this thing I wonder if they subbed the frame manufacturing out and there was some miscommunication. However, you would think they would catch it in the prototyping stages.

As these are my drivers I will be sending Vifa/PE an email linking them to the testing.
 

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Yep, like Charles said, I tested two of these because of the results I got the first time. I thought surely there was something wrong with the first. After testing the 2nd, it's either a design concern or they have serious QC issues.
 

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i received my drivers yesterday, and the t/s measurements seem to echo the results i obtained using a couple methods. properly optimized, and correctly centered, vifa could have had a gem here. nonetheless, i will incorporate this into a project underway, and see what can be achieved, with the drivers excercised with limitations in mind. the measured parameters do seem a bit off from the vifa specifications, but consistent with one another.
 

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dang.. was hoping they'd be a diamond in the ruff!!! probably why they on sale for $85
 

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The only issue with them is that they are not really optimized. If Vifa fine tuned them on the Klippel these would be one of the best offerings. The offset is huge and fixed over stroke so small adjustments can be made to vastly improve the speaker. Maybe the new series are better optimized. The 12" was the only polished driver in the NE series from what I could tell.
 

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well I was wanting them for the bass driver in a home 4 way.. but not gonna work with
test results like that! wonder if there is a way to fix that offset then the x max would come around.. But i;m not gonna pay $250 per driver either..if so I go to an excel or SS unit..or usher.. I know the quality is good. there
 

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well I was wanting them for the bass driver in a home 4 way.. but not gonna work with
test results like that! wonder if there is a way to fix that offset then the x max would come around.. But i;m not gonna pay $250 per driver either..if so I go to an excel or SS unit..or usher.. I know the quality is good. there
I don't know, the Seas we have tested here has a massive offset too, 2.5mm of suspension throw. The Usher?...never seen a Klippel on. The magnesium Excels are also very low sensitivity despite the low verified xmax.
 

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which seas units???
screw sensitivity I got 330/660W / ch... and its a 4 way active.. that should suffice! lol
 

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which seas units???
screw sensitivity I got 330/660W / ch... and its a 4 way active.. that should suffice! lol
Except your coil will hate it, it will compress more and you will lose output to heat. Case in point, the Exodus 7" reached really high temps on the Klippel bench, there is something to be said about high efficiency drivers that goes beyond needing a smaller amplifier.

The Seas Excel Mag. 7" was tested somewhere on this site by Npdang.
 
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