Design for Two 5" Low Power Subs w/ Neo Magnets

[DLHgn]

So here's the deal. I decided to design a new subwoofer enclosure for my small sound system that my girlfriend is currently using. The reciever has a built in amp for all speakers, including subwoofer, and outputs about 50W RMS @ 8ohm at max volume (so i'm guessing around 40W RMS at reasonable level). The speakers I'm looking at are from parts-express. They're the Tang Band W5-1138SM. 5" sub with neo motor. 40w RMS at with a 4ohm 1.25" SVC. I know I would be underpowering them but they seem to sim very well.

Box Specs:

Net Volume = ~1681.3 in^3 (Chamber is 9W x 12.25D x 15.25H)
Port Area = 18 in^2 (9 x 2)
Port Length = 29.75 in
Tuning is ~35 Hz
Using 3/4" Material (Don't know what I want to use yet)

Pics of Box:

Front View


Side View


Pics of WinIsd Graphs:

Transfer Magnitude


Cone Excursion


Port Velocity


Link to speaker manual:

http://www.parts-express.com/pedocs/specs/264-831-tang-band-w5-1138sm-specifications-45662.pdf

What do y'all think?

[DLHgn]

Actually I done goofed. The receiver I have is rated at 100w RMS @ 3ohm 1% THD. Would running it at 4 ohm do any harm?

[bmwking]

Actually I done goofed. The receiver I have is rated at 100w RMS @ 3ohm 1% THD. Would running it at 4 ohm do any harm?

nope, that should effectively mean it's pushing 75w rms at 4 ohm

[bcbrassard]

Nice design on that enclosure. And the TB 5" look pretty suitable for what your building.

[DLHgn]

Hey guys, thanks for the input. I've actually completely changed the design since then.

This is the new design: http://www.stevemeadedesigns.com/board/topic/207284-design-for-one-10-sub/

Would love to see what y'all think.