I need a box plan!

[Qbenjamin 10+ year member]

As I realize that I now need a new box for my Q's, I have just decided to go ported again. I need a design for a dual vented box. I want the chambers to be separated. Not looking for a free box plan, as I am more than willing to pay for someone's time. Here are my max dimensions:

H = 16"

W = 34"

D = 15"

I don't know what I want it tuned to, but I like the low's to hit hard and clean. Maybe like 31HZ? The less amount of depth I use, the better.

Here are the spces on the Q (I have the D1)

Q12

DUAL 1 | DUAL 2

Fs: 28.4 Hz | 27.1 Hz

Re: 0.7 Ohms/coil | 1.4 Ohms/coil

Qms: 05.39 | 5.63

Qes: .49 | .48

Qts: .45 | .44

Mms: 211g | 231g

Cms: 0.15mm/N | 0.15mm/N

Sd: 481cm^2 | 481cm^2

Vas: 48.3 l | 48.3 l

Spl: 85.4dB 1W/1m | 84.8dB 1W/1m

Bl: 10.4 N/A | 15.1 N/A

Xmax: 27mm

Rms: 1000W

Sealed box: .8-1.5 cuft

Ported box: 1.8-2.5 cuft @ 28-33Hz

Sub OD: 12.500”

Cut ID: 11.125”

Mounting depth: 7.000”

Displacement: 0.16cuft

If you have references that would be a plus.

Click to read more...

 

[BrianChia 10+ year member]

Your maximum dimensions are somewhat small for two ported Q12's. Fi recommends 1.8-2.5 ft^3 but this is too large for your maxes so 1.281 was the largest I could go without compromising port area. It is tuned at 32.5 Hz, which may seem high but the small enclosure limits tuning extension to maintain decent port area. Cabin gain and a PEQ should extend response down as far as you'd like.

As far as references, I've designed enclosures for LegendaryLemon, pitbull12888, bigdog829, JustStoppingBy, and SethPhillips.

 

[blimblam 10+ year member]

hey brianchia, what program did you use? that looks useful.

 

[PV Audio 5,000+ posts]

Your maximum dimensions are somewhat small for two ported Q12's. Fi recommends 1.8-2.5 ft^3 but this is too large for your maxes so 1.281 was the largest I could go without compromising port area. It is tuned at 32.5 Hz, which may seem high but the small enclosure limits tuning extension to maintain decent port area. Cabin gain and a PEQ should extend response down as far as you'd like.

As far as references, I've designed enclosures for LegendaryLemon, pitbull12888, bigdog829, JustStoppingBy, and SethPhillips.

As far as references, they mean absolutely nothing after looking at that design. The compression in that port will be so extreme, baby Jesus himself would have trouble not hearing it. You need about double the port area there, and besides, a 1" port is completely unacceptable.

 

[PV Audio 5,000+ posts]

Honestly qben, go with a single chambered box. You simply don't have enough space to do a dual chamber design and get the 2-2.5 cubes that you need for each if you have a divider in the middle. Not only that, but port noise will be inevitable if you have chambers that size with that tuning and those dimensions. What is the reasoning behind needing two chambers? There is no practical use as it is.

 

[BrianChia 10+ year member]

Yeah I agree the port area is ridiculously small, but he wanted two separate chambers and specified a maximum size. Any larger port area and the net volume would have been way too small. My inital design was 0.85 ft^3 per driver @ 35 Hz. Net volume was way too small and was already compromised to meet box size specs. The only reasonable compromise is the port area and 14.5 in^2 for two 1.18 chambers is equivalent to a 6" tube for a 2.55 ft^3 box. Is it optimal for 2 Fi Q's? Hell no. But it can work and is the best that can be done give the requirement specifications.

Initial design:

 

[PV Audio 5,000+ posts]

Yeah I agree the port area is ridiculously small, but he wanted two separate chambers and specified a maximum size. Any larger port area and the net volume would have been way too small. My inital design was 0.85 ft^3 per driver @ 35 Hz. Net volume was way too small and was already compromised to meet box size specs. The only reasonable compromise is the port area and 14.5 in^2 for two 1.18 chambers is equivalent to a 6" tube for a 2.55 ft^3 box. Is it optimal for 2 Fi Q's? Hell no. But it can work and is the best that can be done give the requirement specifications.
Initial design:

No, that isn't an enclosure design. You need to work around problems and get solutions, not say, oh well since this doesn't work, we'll just settle with that. The port size is completely unacceptable, and is in no way a solution to anything.

 

[Qbenjamin 10+ year member]

I need a box for 2 FI Q 12's.........I might have explained what I needed wrong, but basically I will be running only one sub ATM, so I wanted the chambers to be separated so I wouldn't blow my sub.

 

[Qbenjamin 10+ year member]

I am about to be really disappointed if I can't have a ported box......

 

[Qbenjamin 10+ year member]

Hey PV, what if I did 2 10's? I don't really want to, but I DO NOT want a sealed box.

 

[PV Audio 5,000+ posts]

I need a box for 2 FI Q 12's.........I might have explained what I needed wrong, but basically I will be running only one sub ATM, so I wanted the chambers to be separated so I wouldn't blow my sub.

That is a logical reason, but not practical for this situation. What you're facing here is either waiting and having wonderful sound, or being hasty and in thie end have mediocre sound. It's your choise, but I would personally pick the former.

 

[rpfuror 10+ year member]

IMO, which I have stated many times in this forum:

If you have limited space, tit-for-tat, you will have better results using 1 driver in an ideal design, then 2 drivers in a no-so ideal design. IE haveing 2 drivers can end up not producting more output in all cases...