Joe X

Dual chamber because you are driving the subs with separate amps take a look: Enclosure Specifications: Fb = 33.219 Hz Vb = 1.89 ft^3 (per chamber) External Height = 16 in External Width = 30.5 in External Depth = 25 in Port Width = 2 in * All Dimensions in Inches. * Wood Thickness is 3/4 for all Parts. Let me know any questions.

Well yes the amps section would be better for this but OK since you are going that cheap I might as well save you a few extra bucks take a look: http://www.sonicelectronix.com/item_33472_1600W-Kenwood-Subwoofers-and-Amplifier-Bass-Bundle.html?from=857 You can even get a head unit also for the $200.

Exactly DC Audios can work on smaller enclosures.

Well Arc Audio recommends 1.8 cubic feet (per sub) tuned to 32Hz, the enclosure you are using is tuned to 40Hz and is way off spec.. but you like how it sounds.. I am guessing you don't listen to rap like kind of music.

That would not be a problem as those can be found anywhere: http://www.ebay.com/itm/PVC-Sch40-Socket-Slip-El-406-90-degree-Elbow-Glue-/220502085962?pt=LH_DefaultDomain_0&var=&hash=item7912772f33 The problem is make all the dims work.

Try to fit aero ports.

If it sound right don't fix it. but anyways let me know your maximum dims to fit a box and I will suggest a design, also the full dims of the box you are using would be interesting for comparison purposes.

Modified the original post, is just a generic idea of how it looks, be clear that the baffle is 2 layers thick. And yes those subs can take at least 1800WRMS each without any issues.

If you need a diagram for the above suggestion let me know.

Need to specify what type of design you want before having poeple working on it..

Those will fit easily, at about 2.3-2.5 each you probably could fit 3.

The DC Audio XL 15" can work on 3.25 cubic feet each, much more feasible on your space.

Ok so if you don't have whistling anymore then I don't think is th box, port area is not ideal below PA/Vb below 9 but being above 8 will cost you some efficiency but nothing more. Obviously if your box is hitting the amp and have any bad wires or bad connections you may be experiencing distortion when there's a lot of vibration going on, so you may need to check both your power and singnal cables to see if nothing is damaged or loose. There is a simple method to set your gains without any instruments, it's described in any rockford fosgate amplifier manual, are you familiar with that?? if not I will write it down here for you, it will be good enough for dealing with an obvious issue.

Steve, I may be missing something but you started this thread complaining of distorted sound or "clipping", before you added the extra ports you were complaining about port whistling. My question is do you still have port whistling or not, because that's the main sympton of low port area NOT distorted sound which has nothing to do with port area on MOST cases. Better explain what you are experiencing right now, with what songs..what you listen..etc so that the proper advice can be given.

How did you calculate that box?? What are the specs??

So here is a design suggestion based on DD3512 specs and daily tuning: Enclosure Specifications: Fb = 36 Hz Vb = 5.2 ft^3 External Height = 13.25 in External Width = 38 in External Depth = 29 in Port Width = 6 3/4 in Cut Sheet List: * All Dimensions in Inches. * Wood Thickness is 3/4 for all Parts. External Enclosure Parts: Front = 30 1/2 x 11 3/4 Front Internal = 29 x 11 3/4 Back = 38 x 11 3/4 Left & Right Sides: Side 1 = 27 1/2 x 11 3/4 Side 2 = 28 1/4 x 11 3/4 Top & Bottom = 38 x 29 L Port Internal Assembly Parts: Front to Back = 19 13/16 x 11 3/4 Assembles like this: Let me know any comments.

Basically you need to go through a gain settings procedure to make sure you are not soft clipping. 1) you need to defeat all tone controls on the head unit and the amplifier, bass boost, and best disconnect the bass knob that the amp comes with 2) need to set the subsonic filter on the amp to nearly 30Hz. 3) go through a simple gains setting procedure, are you familiar with that?

Are those designs supposed to specific to the dd3512? It would be better if you posted your maximum dims for a box as reference and the car you intend to put that box into.

DC Audio L2 8" for loud, TcSounds epic 8" for SQ are 2 that come to mind.

Ok so your net effective volume is 3.2 cubic feet Your tuning frequency is around 38Hz PA/Vb = 8.8 RF spec is 1.4cuft@40Hz PA/Vb about 11 So you are short on net volume and port area but not sure that can explain your problem. Do you have any electrical system upgrades?

Steve, if it was playing right before despite the noise, maybe is not the amp settings, share your dims, port lengths if it is the box it can be fixed, maybe there is an issue with the data you entered, at least in one machine I know the Torres misbehaved giving ridiculous output.

Right, is a custom design for that sub, not a generic box.

Digital designs unforyunately likes to play with their specs, LAME practice, gathering information on the T-S parameters from different sources would suggest that a single 18 would be louder than the 2 12s on your new dims and a 35Hz tuning. The curves also show that both are meant to be tuned higher.

Here is a design suggestion: Enclosure Specifications: Fb = 34.003 Hz Vb = 4.012 ft^3 Subwoofer Mounting = Flush Mounted External Height = 17 in External Width = 39 in External Depth = 18 in Port Width = 4 in Cut List: * All Dimensions in Inches. * Wood Thickness is 3/4 for all Parts. External Enclosure Parts: Front = 34 1/4 x 15 1/2 Front Internal = 32 3/4 x 15 1/2 Back = 39 x 15 1/2 Left & Right Sides: Side 1 = 16 1/2 x 15 1/2 Side 2 = 17 1/4 x 15 1/2 Top & Bottom = 39 x 18 L Port Internal Assembly Parts: Front to Back = 12 1/2 x 15 1/2 Extension = 9 1/2 x 15 1/2 Assembles like this: Let me know any quesions.

If you want a specific fix you should provide specific data, box dims port lengths, subs and amp you are using. For ex. wrong tuning can lead to that issue but also amp settings can.