Sub Box design???

[Cameron]

Im looking at buying a Digital Designs 9910 or a 9912, visit www.ddaudio.com for more info. i cant get my head around the port sizing i think im going insane converting from inches to cm.

this box is suited for a 12in sub not a 10in its 2.47^ft.
This shows all sizing in inches but my main concern is the port size. Apparently you need 16sq" per cubic foot which means i need (for a 12in sub) 40sq" but when i add up the total port size on the diagram it doesnt compare, i did y12 maths but im still confused! too confused for a sat nite.

pictures curteous of www.ddaudio.com

 

[Cameron]

ohh is anyone able too look at the box design and work out the lenght of the port wall its really hurting my head? the box is 2.47^ft! Thanks

 

[dephilile]

Download versaverter. It’s good for converting just about anything and everything from metric to imperial. I dunno where you’d download it from. Just google it and see what comes up.

 

[harvs01]

the port in this sub box looks way to big
just use a round roll like they normally are and put that in

 

[Cameron]

Yea the port is big, but the sub puts out like 1500rms or 5000peak these dd subs are made to last and for competion, im prolly not gonna compete cos i dont know a great deal about it!

 

[Tasmaniak]

Don't use a round port for this speaker, it simply wont get enought air forced out of it!

Cameron, the only problem I saw with the box was the fact that they built it using 38mm MDF. That thickness is hella expensive and also rare as hens teeth. Convert the plans to use 25mm MDF.

Also, in regards to the measurements... 25.6mm = 1" and there is 27Litres to a cu. ft.

 

[warney]

and too boot ya cant find the 25mm (1in) mdf at bunnings atm ( at oxley qld) there is only 17mm but it still strong but not making the box as heavy....

so ya have to comprise on one for the other!!!!

 

[Cameron]

im finally sane again, i had to ask DD technitians, but for that size box the port need to be 16" long, as for the mdf size on the diagram its 18mm thick, thanks for ppls help..

 

[dephilile]

Don’t get your stuff from bunnings. They are sooooo expensive. I used to work at hudsons timber & hardware (now hudsons building supplies) and we sold 2400x1200x19mm sheets of MDF for like $30 (can’t remember the exact price). At bunnings you could expect to pay that and a little bit more for something not even a quarter that size.

Also, most hardware stores offer a free cutting service. If you buy a big sheet get them to cut it up to the sizes you need. Makes your life a little easier.

 

[Cameron]

Thanks dephilile, i'll keep it in mind,