Hellbilly429 DC Audio Level 4 12" D1 Box

[Hellbilly429]

I've spec'd out a box using WINISD and Torres for my DC Audio Level 4 12" D1, and I want to make sure I get a second opinion on it before pulling the trigger. I plan on doing a plexi-glass panel on the front of the box to show off the motor and basket, so I want to make sure the box is right the first time around.

Here's the sub porn pics:

The sub box is 2.5 ft^3 Net with a 6" aeroport at 22" long tuned to 34 HZ. Plan to use a big ass port with an elbow to accomplish that length of port in this box so that both sub and port fire upwards. Dimensions are 15"hX15"dX33"w with a double baffle on the top (15"x33").

My biggest concern is if this box is too big for this sub. This seems to be the only size I was able to get this sub to play out well in WINISD with 1500 watts being put to it at a 2ohm load. I gained over 3.5 db on the Transfer Function Magnitude chart at roughly 44hz, and managed to keep the Port Velocity below 31.88 m/s peak, peak being at roughly 32 HZ. I also managed to keep the peak excursion at 22.3mm at 25 HZ, so the sub should never bottom out on even the lowest notes.

Does anyone see any improvements that can be made on this design? Or does anyone think this box is too big for this sub, who can manage to get proper port area for this sub with 1500 watts at 2 ohms to it without adding 1+ cubes to the box size in doing so?

Thanks guys!

[Joe X]

Bear in mind that you are playing inside a vehicle, winisd is not designed for vehicle oriented designs, here's in-car theoretical performance of an 1.5 net (yellow) vs 2.5 net (red) @34Hz:

 

 

As you can see at 2..5 net you have a lot more output than the 1.5 around tuning but it's very peaky and that can be annoying to many people, at full output though you may lose some output due to the limited port area.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

[DiBo]

1 hour ago, Joe X said:

Bear in mind that you are playing inside a vehicle, winisd is not designed for vehicle oriented designs, here's in-car theoretical performance of an 1.5 net (yellow) vs 2.5 net (red) @34Hz:

 

 

As you can see at 2..5 net you have a lot more output than the 1.5 around tuning but it's very peaky and that can be annoying to many people, at full output though you may lose some output due to the limited port area.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

Learning myself Joe X. That peakiness is technically the reason for bigger boxes getting "louder" but the more flat response is preferable correct? 2.5 for that DC is too big no matter what winisd said imo. Here to learn tho not assume

[Joe X]

The problem here is that WinISD by itself won't let you see the effects of cabin gain, here's the same 2.5 net plot as above but as it would play outside of a car:

 

 

It would make sense to give 2.5 net looking at that plot but it's not what you are getting inside a car, this is why DC says 1.5, I would probably go for about  1.75 net for daily.

[Hellbilly429]

Thanks Joe X! Was hoping you would chime in. I'd prefer a smaller box, but then I got all tied up in the port area nonsense and port air velocity etc... Then got confused as hell by winisd, lol. My issue is that at 1.5 net, for the port area recommendations for my wattage, it was taking another cube to make a port, which doesn't make sense to me. I'd prefer going with an aero port, so am I screwed with a 4 inch aero in order to keep fort length reasonable? Should I try to make a 6 inch work by using internal and external port to accomplish the length? What is the meaning of life Joe X? Is it to learn that port area recommendations were created just to push us to the brink of madness, and teach us how petty the concerns we have about box design are?

[Joe X]

Small box, high power subs, best is going with a slot port.. by far, anyways if you are wondering what else can be done with round ports, here's a spec based on two 4" round ports, vent airspeed would be 28 m/s @1500W so a little better and net volume is a little smaller too, not a design as such since don't have the flare sizes, ports can go on baffle turning or sideways.

 

Enclosure Specifications:

Fb = 34 Hz
Vb = 2 ft^3

External Height = 14 in
External Width = 32 in
External Depth = 14 in

Cut Sheet List:

* All Dimensions in Inches.
* Wood Thickness is  3/4 for all Parts.

External Enclosure Parts:

2 x Front & Back (3 parts) = 32 x 14

Left & Right Sides = 11 3/4 x 12 1/2

Top & Bottom = 32 x 11 3/4

Port Quantity and Dimensions:

Number of Ports = 2
Pipe Port Diameter = 4
Pipe Port Length = 26 1/2

 

 

 

[Hellbilly429]

Thanks Joe! Appreciate the help! I'm not opposed to the slot port, just thought it would look cleaner with the aero port and sub showing through a plexi panel. If slot gives best results, I can re-design for a slot at around 1.5 net and play around with it in winisd. Now that I know I want to stay away from a bigger box and keep the response more flat to account for cabin gain, I think I can come up with something. Appreciate the knowledge!

[Joe X]

Sure, you're welcome.