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Does the size of the port matter?

 

Thomas
New member
Username: Teltic

Post Number: 5
Registered: Apr-10
Posted on   
I'm assuming it does... I need education. I've been using this RE enclosure thing... http://www.reaudio.com/speaker_box/LPort_Box_Calc.html

I'm trying to build a ported box for 2 audiobahn AW1206T subwoofers...

And I'm looking at the specs for my subwoofer on audiobahns website.. all I do with the specs is I take the total volume (1.5 cu ft) and times it by 2 (since i'm using 2 subwoofers)
http://www.audiobahn.com/Audiobahn06/images/tech/2007/boxParams/AW06T_box_specs. pdf

I want my box 38" by 16" by 13.5"... Basically from what I understand I can have any port size.. but it will tune it in different frequencies... the specs on the website say 40. I'm assuming it stays 40 even with 2 subs. so I will have the square port width at 3.5 and square port length at 7.25

this will make my box at 3.0 cu ft and 40 tune freq. Which is what I want according to AW1206T space saving bass design specs.
 

Thomas
New member
Username: Teltic

Post Number: 6
Registered: Apr-10
Posted on   
image/bmpUpload
Untitled.bmp (84.4 k)


anyone want to tell me what i'm doing wrong or if I did it right?
 

Kyle Longbrake
Gold Member
Username: Kyle_lowe

Post Number: 1037
Registered: Apr-06
Posted on   
looks right to me, but you will need it a bit bigger to account for the sub displacement
 

GlassWolf
Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 13072
Registered: Dec-03
Posted on   
yes it matters.
you need the port opening large enough to prevent port noise, and you need the right diameter (or LxW) and depth to tune the port to a specific frequency based on the box's volume.
 

Thomas
New member
Username: Teltic

Post Number: 7
Registered: Apr-10
Posted on   
@kyle Okay but I just realized I don't need to look at port displacement because this program already has it included. so do I add sub displacement (0.25) with air space (1.3) = 1.55 times by 2 subs = 3.1 cu ft. right?

@glasswolf How do I know how big the port size needs to be? The specs sheet says 3 x 6.75. times that by 2.. But those are round ports... how do I change from rounded to square port?
 

GlassWolf
Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 13075
Registered: Dec-03
Posted on   
by recalculating the entire enclosure.
www.bcae1.com has the calculators available in java form.
 

Thomas
New member
Username: Teltic

Post Number: 8
Registered: Apr-10
Posted on   
I've flipped through at least 100 pages in that site and can't find any enclosure calculator...
 

Kyle Longbrake
Gold Member
Username: Kyle_lowe

Post Number: 1040
Registered: Apr-06
Posted on   
im not exactly sure what you are looking for but is this it?

http://www.bcae1.com/spboxnew2.htm
 

¤Jack_k飣iñgoñ¤
Gold Member
Username: Frkkevin

Team DLSSuperNatural...

Post Number: 7618
Registered: Nov-05
Posted on   
for a daily box with those subs i'd run 12/14 square inches of port per cubic foot
 

Thomas
New member
Username: Teltic

Post Number: 9
Registered: Apr-10
Posted on   
@frkkevin run a 12/14 square inch port per cubic foot? since my box is 3 cu ft I should run 36/42 square inch port? I'm not sure what you mean by 12/14 square inch port.....
 

¤Jack_k飣iñgoñ¤
Gold Member
Username: Frkkevin

Team DLSSuperNatural...

Post Number: 7619
Registered: Nov-05
Posted on   
12-14 square inches of port per cubic foot of the enclosure

so at 3 cubic feet i'd run 36 square inches of port
 

Thomas
New member
Username: Teltic

Post Number: 10
Registered: Apr-10
Posted on   
okay 36 square inches. What frequency is good for ported box? Just a simple every day use... 40? 35? 30?
 

¤Jack_k飣iñgoñ¤
Gold Member
Username: Frkkevin

Team DLSSuperNatural...

Post Number: 7620
Registered: Nov-05
Posted on   
35hz is generally good for a mix
 

Thomas
Bronze Member
Username: Teltic

Post Number: 11
Registered: Apr-10
Posted on   
So correct me if I'm wrong.. but the length of the square port #2 is there to tune the box, doesn't effect square port area.. but it tunes the box.

heres what I got for my box... anything wrong?

image/bmpUpload
Untitled.bmp (65.5 k)
 

Smith
Silver Member
Username: Simple_smith

Lapeer, Michigan United States

Post Number: 396
Registered: Dec-08
Posted on   
Yes that is correct.
 

Thomas
Bronze Member
Username: Teltic

Post Number: 12
Registered: Apr-10
Posted on   
anything I should change before I build the box? Do I need to round off the port piece? someone told me that before....
 

Thomas
Bronze Member
Username: Teltic

Post Number: 13
Registered: Apr-10
Posted on   
Also I don't know if I can afford both subs at once.. can I stick one in for now and buy the 2nd sub later? Or is this box meant for 2 and won't work with just one?

thanks for the help guys. I really appreciate it.
 

GlassWolf
Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 13088
Registered: Dec-03
Posted on   
if you go that route, then make the box divided so each sub has it's own separate air space.
 

Thomas
Bronze Member
Username: Teltic

Post Number: 14
Registered: Apr-10
Posted on   
http://www.audiobahn.com/Audiobahn06/images/tech/2007/boxParams/AW06T_box_specs. pdf

this site shows rec. port size ( 3 x 6.75) that equals 20.25 port area... times by 2 (2 subs) 40.50 port area is what I need? my box I have planned is 36.25... is this a problem?
 

GlassWolf
Platinum Member
Username: Glasswolf

Columbia, SC USA

Post Number: 13123
Registered: Dec-03
Posted on   
for a 12" sub, I would not go any smaller than a 4" ID port tube.
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