Box wuestion please helppp!!!!!!!!!!!

 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 148
Registered: Feb-06
my question is the bigger the box , the bigger the ports? or smaller?

wich is the best tuning freq for sql on a 9.8 q ft for a 18 inch sx thank alot

if u want to know wats the box here:

http://www.accelerator-pedal.com/ported-box.asp?Ew=30&Eh=24&Dia=11&Xmax=8.6&Vd=. 5&NumW=1&Vb=9.81445&Fb=30&Qts=&Vas=&Fs=&CE=1.5
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2542
Registered: Mar-04
try to get 10-12sq inches of port per net cubic foot of the box.

are you the guy that already has a box built (w/ the divider in the middle)? if so what are the diminsions of the box you have built?

if you can get 9.5cuft (net) w/ 100sq inches of port...the port can be 17.5" deep and tuned to 33hz. it would be loud as h3ll and sound dam good.

 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2543
Registered: Mar-04
bump
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 149
Registered: Feb-06
this is the box
Upload


was for two 15 but now is for a single 18 inch sx im going to remove the middle part
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 150
Registered: Feb-06
yes thats me the area is 9.5 cbft and i want a port maybe im going to built a interchangable port i think you show me some pics man that really help and thanks a lot bro im going to do the way you said the sub firing up and the port in the back side
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2544
Registered: Mar-04
w/ a box that big...make sure you brace it.

also...double the baffle.
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 151
Registered: Feb-06
thanks alot man im going to tune it around 32 hz i think im going to do around 110 sq inches of port and you think polly fill is need it or dynamat i already have polyfill so i think im going with that but wat you think
 

Silver Member
Username: Scott_debaker

Pittsburgh, P.A. U.S.A.

Post Number: 130
Registered: Feb-06
marshall how much port area i got 3" wide 14.5" high an 16.75long an how much would b best for the 15 sx an how do u work that program
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2547
Registered: Mar-04
lilrob,

dont use polyfil or dynamat in a ported box.



SPD,

you have since the port opening is 3"x 14.5"...you have 43.5sq inches of port. what is prolly enough for up to a 4.25cuft (net) box.
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 155
Registered: Feb-06
thanks alot marshall but last question
wats the best tunig for sql ( i think is around 30 hz) and wats for spl
 

Bronze Member
Username: Waterboy2289

Martinez, Georgia USA

Post Number: 71
Registered: Jan-06
The FS of a SX 18 is 33hz....I didn't think you were supposed to tune below that with a ported box becasue it would be like the sub is in free air...is that true?
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 158
Registered: Feb-06
i dont know dude but marshall told me to tune it to 33 hz and almost all the people in this forum said that they tuned their boxex from 30 to 35 thats the most common tuning frequesies
 

Bronze Member
Username: Waterboy2289

Martinez, Georgia USA

Post Number: 73
Registered: Jan-06
Well I wish a pro would way in with his opinion since this is pretty important. It makes sense that a woofer would operate like free air in a box tuned below its FS(the free air frequency of the woofer). I would appreciate a reliable answer to this question.
 

Silver Member
Username: Terry6405

Sullivan, IN US

Post Number: 595
Registered: Sep-05
i just saw your design on that box and you had the xmax at like 8 -- its 22mm for my SX15 and i think its the same for the 18 so might try this

http://www.accelerator-pedal.com/ported-box.asp?Ew=30&Eh=24&Dia=11&Xmax=22&Vd=.5 &NumW=1&Vb=9.81445&Fb=30&Qts=&Vas=&Fs=&CE=1.5

and tune accordingly
 

Gold Member
Username: Southernrebel

Monroe, Louisiana USA

Post Number: 2548
Registered: Mar-04
to would tune an SX18 to ~33hz for daily...thats just me though.

if you are going for SPL, its totally different. You would want to tune your box to peak at your vehicles resonance frequency. (You doesnt mean you tune to box TO your res freq...you tune it to peak at that freq...usually the box tuning is 3-6hz lower than your vehicles actually res freq.)

lilrob,

your vehicle is an Explorer...right? those SUV's tend to have res freq's in the ~40-46hz range...that is one reason that SUV's sound great w/ a box tuned low (the 'like' lower frequencies.

but that is also why it is hard to get them really loud (150db+ range)...your see, lower frequency waves carry less energy than high freq wave (ex, its easier to get a 150 is a vehicle that peaks at 65hz than one that peaks at 45hz)

You can get some awesome daily bass out of SUV's, but it just takes alil work to get them in the 148-150dB+ range. (w/ the right tuning and box design, you should be able to get the SX18 in this range...it will just take time, testing, and know-how)

For an SPL port...try 125-150sq inches of port tuned to 38-39hz to start off...then get on a meter and run sine sweeps, cut the port an inch shorter at a time until you get the highest peak.

remember...fire the sub up and the port back...w/ the port mounted cented on the box and pretty low to the floor (~4-5" from the floor, if you use interchangable ports).
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 159
Registered: Feb-06
man thanks alot bro i already move the divider so i just need to make the port but the thing that said matt drouin it also make me think if i tune the box at 33 hz it will act as a free air so wat if i tuned to 35 or 34 or its just a mith and stick with 33 hz
 

Bronze Member
Username: Waterboy2289

Martinez, Georgia USA

Post Number: 76
Registered: Jan-06
there shouldn't be to big of a difference between 33 and 35hz, so I would just play it safe and go with 35. Also, if I were you, I would look around on the internet for information about the tuning of ported boxes and the FS of the subs that go in them.
 

Silver Member
Username: Extrmndor3

Chicago, Ill Us

Post Number: 179
Registered: Feb-06
right now im building the port i make it for 34 hz so its not that low and like all the people around here im doing around 30 hz
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