How to measure and tune a ported enclosure?

[ChrisB4]

I want to build my first ported subwoofer box but I don't know how to measure or tune one . It's going to be for 2 D412" MMATS professional audio Pro cast series rated at 600 watts rms. My current amp is a hifonics brutus 1200.1d, but I will soon upgrade to the 2400.1d. I listen to all types of music(if that helps) I am looking to tune my box to 35 hz, can someone give me info on this. Also, my car is a 1999 saab 9-5. My Max dimensions are 21"L X 38"W X 20" H. I tired to torres box calculator but got confused. The recommended enclosure sheet for my subwoofers say for vented enclosure (net volume) recomends 2.0 cu. ft with a port of 20 sq in x 15"L and Max of 2.5 cu. ft with a port of 25 sq. in. x 15"L

Sorry If I sound like a noob but this is all new to me, can someone help and tell me how to measure and tune a ported box?

Thanks in advance

[Joe X]

So here is a suggestion subs/port front/back on rated power:

Enclosure Specifications:

Fb = 35 Hz

Vb = 4 ft^3

External Height = 17 in

External Width = 37.5 in

External Depth = 17 in

Port Width = 3 1/4 in

Cut Sheet List:

* All Dimensions in Inches.

* Wood Thickness is 3/4 for all Parts.

External Enclosure Parts:

2x Front = 16 3/4 x 15 1/2

Back = 37 1/2 x 15 1/2

Left & Right Sides: 15 1/2 x 15 1/2

Top & Bottom = 37 1/2 x 17

Shared Port Internal Assembly Parts:

2 x Front to Back = 13 7/8 x 15 1/2

2 x Extension = 2 7/16 x 15 1/2

Assembly guide (generic dimensions):

Recommended setting your amp subsonic filter to 29Hz. 45s are 2 1/4 wide. Any questions let me know.

[ChrisB4]

Thanks joe, now I have three questions. What do you mean by wagon? If you are talking about the car it self, I have the sedan modeled saab 9-5. Will this effect the box design? My third question is for the corners. I have a table saw so do I just set it to a 45 degree angle and cut both sides of the wood

to get it to fit in the corners?

Again, thanks joe!

[Joe X]

Thanks joe, now I have three questions. What do you mean by wagon? If you are talking about the car it self, I have the sedan modeled saab 9-5. Will this effect the box design? My third question is for the corners. I have a table saw so do I just set it to a 45 degree angle and cut both sides of the wood

to get it to fit in the corners?

Again, thanks joe!

Ok I just specified this to you so that it could be changed which now is (above), you have 20H which is infrequent in a trunk car, in this type of vehicle you should be careful to make sure the box fits in the way in, if it's hard to tell, building a cardboard dummy box can help, also the dimensions of the box can be adjusted to avoid to build inside the trunk if possible, on the 45s, those are optional, some people are for and others against it's use, the ones inside the port have to be done very carefully or will actually hurt performance, you will need to slant the port corner as shown and make sure the width of the vent to each lateral duct stays exactly 1/2 of the port width:

If you need some more detail on this let me know.

[ChrisB4]

Het joe thanks again, I'm now about 90% done with the box but the only thing that is giving me trouble is the two 45s in the middle of the port. You said it needed to be exactly 1/2 on both sides or there will be a huge difference, but for the life of me I can't get them to line up exactly. I need to know if I done use them will that change to whole tuning frequency of the box or will it just affect air flow?

[Joe X]

No it will not have a significant effect in tuning, arguably it can have an effect on sound quality and you may experience other effects derived of turbulent flow, regardless, some people who have failed to do them reported good results anyway BUT doing them incorrectly could be actually much worse than not doing them at all. So try to get them right and if you really can't then leave them out.

[ChrisB4]

Hey joe, thanks again for the box I moved it into my other car. So I wanted to know if you can work you magic again for another box. I'm getting my subwoofers (mmats pro cast series) rebuilt to 1000 watts rms. My max dimensions are 16h x 36w x 18d tuned to 32hz It's going to be for the saab 9-5 again. I will be getting the hifonics Brutus 2400.1d the reason I want it a little smaller is because I plan to seal it off from the trunk is it also possible to get the subs to the left and the port to the right? I want to do the flush mount and I think it will be easier with the subwoofer on one side.

Thanks again if you take the time to do this for me.

[RogeyD]

Hey Joe I see you are very knowledgeable about ported boxes would you mind helping me out some I have spent the last two weeks immersed in trying to figure out how to build a ported box I've used several different box calculators and am only more confused by them now , I'm trying to build a box for my two infinity reference 1060 10" subs, the manufacturer calls for 1.75 ft³ at 35hz, by using a 3" round port at 4.75" Long however when I plug those numbers into any calculator including the t/s parameters I get all sorts of screwy number and different Hz tunings , would you mind helping me walk through some of this stuff so I can maybe finally understand ported boxes and build my own as I'd very much like to be able to do .

[RogeyD]

If you wouldn't mind helping out ll I'm attempting to figure out a dual enclosure for these tens , using round ports to save on space some , the t/s parameters of the subs are as follows : qts= .42 , qms= 7.59, vas= 1.16ft³, fs=29.00,MMS= 173 grams, xmax =.512 in, bl= 16.02, SD= 56.265in², SPL=91, re=3.59, peak power handling is 1000w with an RMS of 275 per sub. The amp I have is rated at 300w RMS @ 4 ohms and 500 RMS @ 2 ohms . now what I'm attempting to achieve with this set up is most likely a 3.5ft³ net enclosure with a tuning of 33hz unless a different tune would work better. The car itll be going Into will be a 2005 Camry , and the space That I have to play with is 36in wide by 17 in deep by 16 inch tall, I'm attempting to build a ported box that is more on the sq side of things being that I listen to all types of music sgy of tejano and polka, I'd just really like to to make the jump from sealed boxes to ported , again any help would be Extremely appreciated.

[ckeeler11]

i would recommend starting a new thread. this one is 4 years old.