re sx 15's and airspace

[matrxx dude 5,000+ posts]

thought i would share some of my info,ive been changing enclosures and volume and the way subs fire,and the way port fires,heres wat ive tried,ive tried a box 8 cubes tuned at 45 hertz,the way it is in my avator,subs and ports firing back,done ok,then i tried a 6.5 cube box ,crx style ports back and subs up lost a couple of db's,then i tried a 5 cube box with the port between the subs tuned at 45hz,subs facing back and port of course,this box outdone everthing else ive tried so far,im doing all this in a 98 ford explorer,so to me sx's dont like as much air space as re says,they beat harder and do better numbers in the last box i built,im open to any and all suggestions to make my vehicle louder,currently still only 148 on tl with 2400 watts rms,got to be a way besides doubling the power to come up to 150 on tl.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

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[matrxx dude 5,000+ posts]

no opionions

 

[QualityCarErock 10+ year member]

We got 2 SX 12'S doing over 150 on the dash with an Us Amps 2000 on them so i'm sure if you have a true 2000 watts "rms" on the 15's right off the bat with the difference in effenciency you should be atleast 3 db's louder since the 15's at 1 watt are 93.7 with two and the 12's are only 91.1 at one watt.

 

[QualityCarErock 10+ year member]

Not to mention that you have way more equipment/upgrades on your car then he does. He has a 80 amp stock alt. with an aux battery. You have an h.o. alt. Big difference in voltage i'm sure. His is dropping pretty low after you beat on it for a few minutes. Check all your connections and make sure your voltage is solid. Loss of voltage and a weak ground could cause your amp to not perform as well as it's capable of although i have no experience with the amps your using.

 

[ramsizzle 10+ year member]

^^ you really know nothing...first u dogg great budger amps in power acoustik adn u say stupid things liek the sensitivity should make them do 150, whats wrong with u lol?

 

[toaster 10+ year member]

sensitivity has very little to do with real world SPL.

put them in 11 cubes, fire them back, port in MIDDLE, tune it to 50hz.

youll get 150.

 

[matrxx dude 5,000+ posts]

11 Cubes,kinda Big But If U Say So Ill Try It,how Bout My 8 Cube Box In My Avator,ive Done A Little Rearanging On It Though,i Got Subs Firing Up And The Same Ports Firing Back,i Put A 3'' Pvc Half Above The Ports To,give Me Some Advice Toaster On Why I Cant Get That Box To Get Off 41hz,ive Tried Trimming The Ports,and It Still Stayed Around 41hz But Lost A Db

 

[toaster 10+ year member]

11 Cubes,kinda Big But If U Say So Ill Try It,how Bout My 8 Cube Box In My Avator,ive Done A Little Rearanging On It Though,i Got Subs Firing Up And The Same Ports Firing Back,i Put A 3'' Pvc Half Above The Ports To,give Me Some Advice Toaster On Why I Cant Get That Box To Get Off 41hz,ive Tried Trimming The Ports,and It Still Stayed Around 41hz But Lost A Db

your box is tuned too low for outright SPL.what is the internal size of box, gross, and what are your port dimensions?i need to know the answer to this before i can help further.

 

[toaster 10+ year member]

for an 11 cubes box, using 140 square inches of port area, the port would need to be 3.25 inches long to tune @ 50hz.

just dont play alot below that, or youll be reconing

 

[matrxx dude 5,000+ posts]

I Can Give U Outside Dimensions Right Now,something Ucan Kinda Work With,42'' Wide,20 3/4'' Tall,22 '' Deep,top Plate And Back Plate Are Doubled With 3/4 Mdf,the Ports Are 20'' Wide A Piece,2 1/2 '' Tall And 11'' Deep.

 

[toaster 10+ year member]

for 8 gross cubes, with 140 on the port, the port would need to be 12 inches long.

 

[toaster 10+ year member]

the box you now have is tuned @ 41hz.

i dont like how narrow they are, either, but thats just a personal opinion. may or may not hurt.

the port area you have now is 100 square inches, which is really not enough port area. imho, you need @ least 140.

but, the port you now have should be 2.5 inches long to tune @ 50hz.

hope that helps.

 

[matrxx dude 5,000+ posts]

Im Not A Pro A Boxes As U Can Tell,u Said My Port Should 2.5 Inches Long,wat About Height And Depth,better Yet With My Current Box Can You Draw A Schmetic Kinda Of Wat Ur Talking About,because Bj Says U Really Know Ur Stuff And I Would Like To Take And Print This Out And Carry It To My Box Builder And Me And Him Rearrange Stuff To Get The Most Spl

 

[toaster 10+ year member]

ok, check it out.

3 options:

1. leave your ports height and width the same, but cut them off to 2.5 inches long (the actual depth of the ports).

2. seal those ports up. go and get a stick of 6 inch pvc schedule 40 pipe. cut off 5 pieces, 11 inches long, and cut 5 6.5 inch holes in the back of your box. then mount them in the holes. brace between each port with threaed rod, because that many ports will weaken the rear baffle. or, get aeroports if you can. makes a BIG difference in SPL.

3. cut a rectangle into the rear baffle that will equal 140 square inches, and make that port 11 inches long. remember, square inches = width x height.

out of those, i would do the pvc ports. much easier to change tuning. and, aeroports PWN

oh, and BJ is not too bad, himself