Joe X

If nothing else moving the port to the top of the side could reduce the potential load.

Ok since I don't know where you got at, im just going to show you what I was going post to before the dims mess, so a dual layer baffle surface and a 33hz tuning should give you something very close to this: Enclosure Specifications: Fb = 33,029 Hz Vb = 6,465 ft^3 Subwoofer Mounting = Flush Mounted External Height = 22,5 in External Width = 41,5 in External Depth = 18,25 in (because of the double baffle) Port Width = 3 7/8 in 2 x Front & Back (3 parts) = 41 1/2 x 22 1/2 L Port Internal Assembly Parts: Front to Back = 12 1/8 x 21 Extension = 3 7/16 x 21

Here is the response plot if the aq sdc 2.5 4cuft@33Hz: The HDC315 behaves very differently than this sub in the same box: With the typical gain dip just above tuning frequency so 33Hz is bad for the HDC3 on 4 cuft but not so for the sd2.5.

That sounds perfect to me, although, are you sure about the 26hz? I used the torres calculator and double checked it, comes out to 33hz. I just realized my measurments were off, the box is 17.5inches tall once the 3/4'' mdf is accounted for. Also, Bear in mind the port is on the side that is 21inches tall. however, I think i've got it figured out. My box is actually 6.95 cuft. and the port can be 3.7inches wide and 30 inches long I think you may be confusing external dimensions and internal dimensions measure the external dimensions on the box (yes add 0.75 to the depth because the baffle is not installed) and then substract 1.5 inches to each one and those are you internal dimensions, the INTERNAL height is the height of the port.

Ok so for a SSD 18 Fi recommends this: Ported box: 6-10 cuft @ 33Hz Driver displacement for that sub = 0.22 cuft. Assuming you are giving internal dimensions and with the port you specify your box specs as follows: Fb = 26,952 Hz Vb = 6,305 ft^3 Port Area/Vb = 9,993 So you are tuned low and port area is low. Recommendation is as follows use a double layer baffle, change port width to 4 in, and retune to 33Hz. If you like that I will let you know the size of the pieces of wood you are missing to make the L port.

I was just wondering, you are really doing a slanted box right?? asking because you mention ease of build as an issue.

In that case you could do as follows, ports are still top mounted: Enclosure Specifications: Fb = 33,236 Hz Vb = 6,447 ft^3 Subwoofer Mounting = Flush Mounted External Height = 24 in External Width = 48 in External Depth = 14,5 in Cut List: * All Dimensions in Inches. * Wood Thickness is 3/4 for all Parts. External Enclosure Parts: 2 x Front & Back (3 parts) = 48 x 24 Left & Right Sides = 12 1/4 x 22 1/2 Top & Bottom = 48 x 12 1/4 Port Quantity and Dimensions: Number of Ports = 2 Aero Port Diameter = 6 Aero Port Length = 17 Try to install the ports far from each other an from the walls. The design calls for flush mounted subs, it's a good idea to perform it due to the way they are going to be installed. Also note that some (mainly front to back) crossbracing would be beneficial.

Ok friction losses decrease on the center duct, the V shaped piece will align the flow and avoid some turbulence but nothing more. Probably no big deal but still will tune differently than the standard port. I am guessing it will tune higher.

Xmax is specified as one way and in the linear BL region so to speak "usable" region. Which to choose don't depend solely on this.

Yes, I just need the maximum dimensions he has to work with and will work something out, if you can run the Torres you can verify what I put out or design something and I could tell you if see any issues.

Yes you can smooth turbulence and I guess it can be done succesfully is just that aispeed lowers on the center duct and therefore the standard tuning equation would be inaccurate by some margin, I would just love to see some analytics for that situation.

If the center divider cuts the port as well it would be a standard L port, port up, when possible (when you have enough width) is best to have ports and subs on the same face.

Yeah, I have seen those but because the air speed lowers on the common center duct an there's a lot of turbulence on the T I think the standard equation will not predict accurately tuning and I expect lower sound quality on such port design, to me just placing a center divider there makes things more predictable.

Just post your dims on your build thread.

Yes 2 chambrs - 2 ports for the reasons explained. I have not seen equations to model port tuning for a 2 chamber single center port design. As for a single chamber center slot port it can be easily done IF the port does not turn.

This thread will be out soon so decide what will you be using and post a build thread, from there I can calculate your box or you can use the Torres calculator, My vote goes to Fi easily from those two.

If you do separate chambers you will need two ports, is a bit harder to build and and a larger box but because drivers can't load each other (due to individual tolerances) some energy is saved and some better sound quality is achieved, some people use separate chambers because of this, at least one kicker box design document also support the use of separate chambers. The center divider provides some "natural" bracing also.

If you want a design suggestion for a 2 cuft I can provide it or you can use the Torres calculator.

What program are you using? the fewer ports you can manage, the better. less turbulence. box designing is more than throwing some random numbers up on a calc.. He was set on using 4" aeros..

You have 46,5 inches wide , 5 ports 4 inches in diameter are 20 inches, 26,5 inches for the subwoofers, i think that properly placed everything can fit with some effort.. can't think of anything else anyways.

Note that I am suggesting to install them in the top face of the box, is possible since you have 24 inches of height. You would place the subs on the front or back.

What amp and subs are those?? Also to reach a conclusion you need to control your variables very well, don't know if you are doing those tests with a signal generator or what.

If you have any questions just post them here, I also checked the 0.9cuft suggestion and it looks really bad, I almost guess that sealed would be better for them than their ported suggestion, those subs have very low EBP.. if you are curious I could post some frequency response plots for you to see.

I modelled this driver out of curiosity and found that it works great at 2cuft@32Hz at rated power of 300W. It's a gigantic enclosure for a 10" but it works giving bass down to 30Hz. You may want to try that.

Yes it says 0.9cuft@32Hz for a ported box, a 4th order improperly designed or built can be a disaster. If you need lows just skip the sealed, the manual states exactly how to build the ported.