Hi all...
I'm using a single NVX VCW124 in a 1.5ft^3 sealed enclosure. I've been trying to figure out the F3 of this combo but cant seem to get winisd to accept the t/s parameters for some reason. I also tried to figure it out using some math formula i found online but that too didnt pan out. I'm sort of at the end of my rope here. I'm happy with the set up, this is just a nagging curiosity that driving me crazy.
t/s parameters-
Xmax 20 mm
Fs 26
Vas 33.79 L
Sd 73.06
Qts 0.465
SPL 85
QES 0.490 1
I'm using a single NVX VCW124 in a 1.5ft^3 sealed enclosure. I've been trying to figure out the F3 of this combo but cant seem to get winisd to accept the t/s parameters for some reason. I also tried to figure it out using some math formula i found online but that too didnt pan out. I'm sort of at the end of my rope here. I'm happy with the set up, this is just a nagging curiosity that driving me crazy.
t/s parameters-
Xmax 20 mm
Fs 26
Vas 33.79 L
Sd 73.06
Qts 0.465
SPL 85
QES 0.490 1
Ah, I see the problem.
Most simulation programs take Sd in square centimetres, and it looks like you've got square inches. You'll need to convert.
I'd expect some very wonky results with the program thinking it has the area of a ~3" cone.
Chris
Hmm, these only partially match published, Qes, Qts are way off: NVX VCW124 12" Dual 4-ohm VCW Series Car Subwoofer
IIRC, you only need Fs, Vas, Qts for WinISD to calculate a basic box response.
GM
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Im pretty sure I did the conversion in winisd, but Im going to try it one more time right now and post what it says.
Make sure that you use consistent units.
If you use Vas = 33.79 liters, then Vb also needs to be input in liters.
Notice that 1.5 ft^3 = 42.5 liters.
For metric system, use Vas = 33.79 liters and Vb = 42.5 liters. (or if you want to stay in cu. ft., use Vas = 1.2 ft^3 and Vb = 1.5 ft^3)
Also, for a closed box, you should try to find a size for Vb that gives Qc = 0.60 or possibly 0.71 if reasonable. The manufacturer data in a previous link indicates an opitimum closed box size.
If you use Vas = 33.79 liters, then Vb also needs to be input in liters.
Notice that 1.5 ft^3 = 42.5 liters.
For metric system, use Vas = 33.79 liters and Vb = 42.5 liters. (or if you want to stay in cu. ft., use Vas = 1.2 ft^3 and Vb = 1.5 ft^3)
Also, for a closed box, you should try to find a size for Vb that gives Qc = 0.60 or possibly 0.71 if reasonable. The manufacturer data in a previous link indicates an opitimum closed box size.
they claim a .8ft^3 sealed box will yield an F3 of 37hz. Winisd has my 1.5ft^3 sealed box at F3 40hz. It may be splitting hairs but something seems off. In a box over 50% larger shouldnt the F3 freq go down?
The manufacturer will put whatever numbers look good on their products.
-3dB from what? The high-Q peak? 100Hz? Somewhere else?
You can see for yourself what'll happen as you vary cabinet size in WinISD.
Chris
Your answer, based on sealed box theory, is 40Hz
Qtc = 0.62 will benefit from closer-to-boundary location, than what might be visually appealing. This seems like a small driver, so real world F3 might not agree with theoretical F3.
Hi Scott L,All
Your Calculation could be correct if the given T/S Parameters are reliable..But they are totally screwed up or fake
, so your calculations of Qtc and f-3dB is worth nothing as the given Parameters consistency fails if an examination uses cross calculation.Have a look at:
https://www.diyaudio.com/forums/att...-help-finding-f3-enclosure-nvx-vcw124-dvc-jpg
b
Hi Scott L,All
Your Calculation could be correct if the given T/S Parameters are reliable..But they are totally screwed up or fake
Have a look at:
https://www.diyaudio.com/forums/att...-help-finding-f3-enclosure-nvx-vcw124-dvc-jpg
b
Sorry, I did not know they were fake. I was just trying to help, but as you know, "No good deed goes unpunished"
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