Rockwood NY6510 cabinet design and online calculator

[Panciz]

I want to build a cabinet form a Rockwood NY6510 subwoofer.
In order to get an idea of the cabinet design I use two online software:

The one from ajdesing and the one from diyaudioandvideo .
with the same input parameters, I get from the speaker datasheet

Fs = 55.7 Hz
Qms = 3.5
Qes = 1.2
Vas = 17.0 lt
Qts = 0.9

I choose

Qtc = 1.0
Port diameter = 10cm
Ported Box desing

I'm confused since I get two completly different results using the same input parameters .

From diyaudioandvideo I get

Vb = 8.48 ft3 = 240.15 lts
= L x W x H
f3 = 17.37 Hz
fb = 24.51 Hz
Dv = 1 in = 2.5 cm
Lv = -0.39 in = -0.98 cm

But from ajdesing
I get a negative f3 = -29 and the fb = Fs = 55.7.

Did I made some mistake? Which online sfw should I trust?

The results for the closed box design are the same for both the appliations:

Vb = 2.56 ft3 = 72.47 lts
= L x W x H
f3 = 48.65 Hz
fb = 61.89 Hz

Thanks

 

[Inductor]

No sub.
Throw it in a sealed 40-50L cabinet an call it a day.
Also possible/adequate OB.
http://boxenbastler.de/Rockwoodny6510