Help with 18" Box

[Drmmr4life 0]

I have a DC Level 4 18 m2 on the way and i want to make the box before ite gets here (cuz im so impatient)

going in a 99 grand cherokee

listen to all types of music but i do like playing down to like 27 hz or so

powered by an american bass HD 3500 (1600rms)

id like double baffles

max dim are 40 wide 30 deep and 20 tall

i think that about covers what is needed. any help would be awesome! thanks guys

Edited June 27, 2012 by Drmmr4life

[Frostedflakejake 148]

Why are you wanting to build another box when you get the 2 kilowatt amplifier?

[Frostedflakejake 148]

And I'm assuming you want it ported? How about a net cubic feet you're shooting for...

[Drmmr4life 0]

thats what i forgot is cubes!! haha im not sure to be honest, according to DC it says 6 cubes net i believe, and correction. itll be running off an american bass HD 3500 so around 1600rms and because it might take a while to get a diff amp, prob a dc 2k or 3.5k

[Frostedflakejake 148]

Yeah, but why change boxes just because you change amps? That's why I'm confused...

[Drmmr4life 0]

make it smaller because ill be over powering the sub. . . a lot lol.

[Frostedflakejake 148]

Ah I see. Sorry. I always adjust gain instead of adjusting box sizes. I find it easier.

[Drmmr4life 0]

true, but then your not getting the most power from your amp (depending on a lot of things) but yeah, ill have this sub, box, and amp for while. . . .besides, i like building boxes (: im not crazy good yet and each time it ets better so its fun for me. . . but anyways. still looking for anyone to help much thanks!

[///M5 2,833]

listen to all types of music but i do like playing down to like 27 hz or so

How you'd pick 27Hz?

make it smaller because ill be over powering the sub. . . a lot lol.

Why?

true, but then your not getting the most power from your amp

What difference does that make?

*I'm not saying you don't have valid answers, but in general most people wouldn't and the box should encompass the situations that the driver will be in.

**And yes, many questions are loaded in that you may be doing things that will not do anything for your overall goals....but if your goals don't match, why do them. It may be though that you are on the right path. Just impossible to make any box recommendations without knowing, unless of course the answer is follow their spec.

[Drmmr4life 0]

27hz was rough estimate and because the songs that i know that play low are around that. . . doesnt making a box smaller help the sub handle takeing more power than rms. . . im still new to car audio and if im wrong please do correct but thats what i was under the impression of. . . and my box request specs are loose because i dont have the sub yet, i dont know what tuneing and box size they tend to like thats all

[///M5 2,833]

How do you know the songs you play are that low? Are you willing to give up other frequencies to play those?

If you don't know how the smaller box affects your response and power handling it wouldn't be recommended at all. The real question here you missed it wasn't about making the box smaller, but why you want to "overpower" the sub?

[Quentin Jarrell 671]

Box size will change mechanical power rating not electrical. But why would you purposely use an inefficient enclosure just to run more power if you have the space.

27 hertz is way too low. I'm sure you want loud so more than likely a box around 6-7 cubes tuned around 32 hertz will give a nice boost in output in the mid 30's range (although I haven't modeled the sub this should be a good starting point)

Go to the12volt.com and read everything on that site to inform yourself a little. It would take a 2 hour conversation to explain why to go one route or another with out a little basic knowledge.

[Drmmr4life 0]

Box size will change mechanical power rating not electrical. But why would you purposely use an inefficient enclosure just to run more power if you have the space.

27 hertz is way too low. I'm sure you want loud so more than likely a box around 6-7 cubes tuned around 32 hertz will give a nice boost in output in the mid 30's range (although I haven't modeled the sub this should be a good starting point)

Go to the12volt.com and read everything on that site to inform yourself a little. It would take a 2 hour conversation to explain why to go one route or another with out a little basic knowledge.

i didnt say i want to tune to 27 hz, but play 27 hz, (my box now is tuned at 32 and i can play that low. . .

and i guess i dont want to sacrifice that much, and i brought them into a program and found that freq being played thats how i know (and i play sweeps)

[98exploreron22 0]

17'tall 40'wide 30'deep--------- port at bottom ------- 6'tall 18'wide 22'deep ------------

Edited June 27, 2012 by 98exploreron22

[ssh 924]

Box size will change mechanical power rating not electrical. But why would you purposely use an inefficient enclosure just to run more power if you have the space.

27 hertz is way too low. I'm sure you want loud so more than likely a box around 6-7 cubes tuned around 32 hertz will give a nice boost in output in the mid 30's range (although I haven't modeled the sub this should be a good starting point)

Go to the12volt.com and read everything on that site to inform yourself a little. It would take a 2 hour conversation to explain why to go one route or another with out a little basic knowledge.

i didnt say i want to tune to 27 hz, but play 27 hz, (my box now is tuned at 32 and i can play that low. . .

and i guess i dont want to sacrifice that much, and i brought them into a program and found that freq being played thats how i know (and i play sweeps)

Read about Hoffman's Iron law: (http://www.salksound.com/wp/?p=56), and you should have a better understanding why the idea of using a smaller enclosure in order to use more power in order to gain output is rather counterproductive. If your trying to save on space then perhaps you'd have some ground to stand on.

As to the idea of playing frequencies well below the tuning of the enclosure, that's not exactly a hot idea. There is a reason why people use Subsonic filters / HPF for ported enclosures and the alike.

Without a SSF, the speaker's excursion can dramatically increase when playing frequencies below the tuning of the enclosure. This can tear apart the soft parts of the driver if over-excursion occurs enough.

Here's a picture:

Driver used: Rockford Fosgate RFD2218, modeled with 1watt, with a 30hz tuned enclosure. Units for excursion are in um and mm.

As expected, at the enclosure tuning (30hz), the excursion is considerably low. Upwards it increases, and eventually lowers in the mid 40hz range.

The interesting part is the excursion from 30hz towards 10hz, it skyrockets reaching upwards of 1mm. Now 1mm doesn’t seem like much excursion, but remember this was modeled with 1watt of power, and the driver has an RMS value of 600watts.

With the use of a SSF set a few hertz below the tuning frequency (in our case 30hz), the frequencies below 30hz can be attenuated enough that excursion is vastly reduced, and in end, keep the driver in a healthy range.

[Frostedflakejake 148]

17'tall 40'wide 30'deep--------- port at bottom ------- 6'tall 18'wide 22'deep ------------

Would give him too big of a box and a 35hz tuning.

I would do 17" tall, 38" wide, and 28" deep. L-style slot port that is 6 inches wide and a total of 30 inches wide. Do you understand how to implement L-style slot ports?

Brings a tuning of about 32hz with a net cubic volume of 6.11 cubic feet and 14.5 square inches of port area per cubic feet of box.

But it's obvious that you have more questions that need to be answered, but that's a basic box I would build.

[///M5 2,833]

I really wanted to see that 17' x 40' x 30' deep box fit in a car.

Ought to fill around 62 12yard dump trucks and that doesn't even include the port.

[ssh 924]

I really wanted to see that 17' x 40' x 30' deep box fit in a car.

Ought to fill around 62 12yard dump trucks and that doesn't even include the port.

Wait what? I thought ' and " were the same thing.

[Drmmr4life 0]

feet and inch bro feet and inch

[Drmmr4life 0]

17'tall 40'wide 30'deep--------- port at bottom ------- 6'tall 18'wide 22'deep ------------

Would give him too big of a box and a 35hz tuning.

I would do 17" tall, 38" wide, and 28" deep. L-style slot port that is 6 inches wide and a total of 30 inches wide. Do you understand how to implement L-style slot ports?

Brings a tuning of about 32hz with a net cubic volume of 6.11 cubic feet and 14.5 square inches of port area per cubic feet of box.

But it's obvious that you have more questions that need to be answered, but that's a basic box I would build.

might start with this unless anyone else can help me out??

[ssh 924]

Either learn the basic fundamentals, or pay someone whose competent in making designs and a cutout sheet.

[ssh 924]

Since I just typed out the similar, see:

[Frostedflakejake 148]

might start with this unless anyone else can help me out??

I mean, I don't know what else you are looking for. It's very close to your target size, I used 32hz tuning cause you said you have it now and like it, and it has an appropriate amount of port area.

[Drmmr4life 0]

might start with this unless anyone else can help me out??

I mean, I don't know what else you are looking for. It's very close to your target size, I used 32hz tuning cause you said you have it now and like it, and it has an appropriate amount of port area.

Touche. . . where should the sub cutout be? obv on top but does it matter where?

[Frostedflakejake 148]

On the opposite side of the port is where I would put it. I would build sub facing up, port facing trunk.