Unibox vs. WinISD for sub box calculations?

[Finleyville]

Anyway...

I have an old Adire Koda 10 sub not being used and thought I would try my hand at my first sub.

Plugging in all the driver's parameters in both programs gives me some serious deviations between them.

Modeling for a total Qts=0.707 the suggested volume from Unibox is 22.6 liters while WinISD figures it to be 37.3 liters. I think that is quite the difference.

I double checked each program's driver stats to make sure they are both the same.

Which should I use?

Adire Koda 10 MkI

Re= 2.8 ohms
Le= 1.3 mH
Fs= 28 Hz
Qms= 3.50
Qes= 0.42
Qts= 0.38
Vas= 85L
Sd= 344 cm^2
Xmax= 18 mm
Pmax= 300 W

[ThomasW]

I've compared Unibox against LspCAD and Bass Box Pro, they all gave similar results. I don't use WinISD.

Without seeing screen shots of your models it's difficult to know what's occurring..

[minkuni]

Are you sure the T/S parameters are correctly stored in WinISD? It is EXTREMELY picky about the order in which you input the data. I always have to read the instructions to get that right when I use WinISD (which is not often, since I have LspCAD which I much prefer).

[Dennis H]

They all use the same math but the assumptions may be different. I'm guessing you told Unibox to use heavy stuffing. To change stuffing in the pro version of WinISD, click the Advanced button and set Qa to a number smaller than the default 100. WinISD also lets you set the series (wire) resistance. The default is .1 ohm and more resistance raises the Q. The pic shows what happens in WinISD when you set the series resistance to 0 and Qa to 6.

[Finleyville]

Thanks Dennis. I think that is what is happening. I think I will model my new box off of around 23 liters. Thanks for all the help people!

[Dennis H]

Personally, I'd go bigger. Qa=6 is close to being overstuffed and Fc of 63 Hz is really high for a sub. All subs need EQ but you'll need less EQ and less power with a bigger box assuming you want it to reach down into the 20s.