sub box shape

[white04alero]

does the shape of the box matter?

for my kickers that i ordered tonite, i'm making the box a 14" x 14" x 15.5" box. this makes it right at 1.75 cubic feet. (about 1.7538)
is a cube a good box shape or should i go different

[antichrysler]

shape doesn't matter.... it's all displacement

[Gr1m]

your supposed to research what size box your subs hit the hardest at and then make that size box.

[foosedgrandam]

also u need to brace the box too

[white04alero]

i did research the size, and 1.75 ft is perfect, especially if i want to go ported later, i was just wondering if the size mattered.. but if its just displacement, and the size doesnt matter, then im good. thanks guys

[white04alero]

and what do you mean brace the box? to the car? or inside the box??

[icpurplepplalot]

trust me with those cvr's you won't need to brace it, just make sure you use 3/4 mdf

[white04alero]

ok, i used 3/4 mdf board.. and the boxes are finished execpt for the front, its going to my dad's machine shop to get the 12" circle cut out... then itll be put onto the box.. and then itll be carpeted

[white04alero]

one more thing.. if i were to port the boxes, what frequency should i port them to? and how long should the tubes be and the hole

[antichrysler]

you could port the boxes..... but i wouldn't recommend it unless you know exactly what your doing.

the size and length of the ports is dependant on the sub and how big of a box you're making. If you're making the box for 1.75ft^3 then odds are for a ported you'll need the box to be around 2.25ft^3 and then you'd have to calculate out the length of the port. From where you're at right now I would say just leave it as sealed and you'll be happy.

[white04alero]

recommended for sealed: 1.0 ft^3 to 4.6 ft^3
recommended for ported: 1.75 ft^3 to 2.25 ft^3

[icpurplepplalot]

Are you wanted to vent it or use aeroports? WHen I build ported enclosures, I always use the "vented" or "L port" method.

[antichrysler]

you're doing 2 12's right?

[white04alero]

yeah in single boxes, and im talking about ports.. the circle holes with the tube in them

[antichrysler]

ahh best bet... download winisd

try to tune for 40hz with a delay less than 10ms... even 10ms is borderline for me... especially if your listening to rap music and such... that'll give you what you need

i know in my old ported box (phoenix gold 12") it was 3" wide and about 10" or so deep... don't remember off the top of my head though... so i wouldn't use those values

[white04alero]

i have winisd.. but i just dont know how to use it after you put in all the parameters.. im winisd-tarded

[white04alero]

and i have one more question.. about the subs.. ok.. right now i have a scosche 550 watt max amplifier.. and i am getting the money for the 500 dollar 750wrms kicker amp to power the 2 subs.. now.. my q is can i power the 2 subs with the scosche for a while and then hit em with the 750 or should i just wait and install them when i get the 750? will underpowering them so much with the scosche hurt them? its a 150 dollar (buy one get one free) investment that i want to make work for me when i can.. so can anyone help me? will the underpowerment of my 550 watt max amp hurt the nice 400 wrms of the kickers?

[antichrysler]

nah... you'll be fine. The only time underpowering speakers is an issue is if your max power is about 15-20% of what the sub can handle. If you're at about 50% you'll be fine.

[antichrysler]

As for WinISD I'll see if I can do anything tomorrow. I don't have it installed and I'm at work till 5 and then I'm visiting my folks this weekend.

[white04alero]

i appreciate it thanks

[icpurplepplalot]

first off, a ported box isn't only aeroports, the tubes, there is vent porting, and L shaped porting as well, both of which are basically the same thing.
If you listen to rap, you are going to want to tune your box alot lower than 40hz as previously mentioned, b/c rap has alot of lows in it. Try like 32-34hz and that will give you the lows for rap.

[antichrysler]

Okay... so here's a quick WINISD Tutorial
1. Open WinISD
2. Click New
3. Select the Driver (Speaker) you are putting in the box. If it's not in the list press New and add it. The specs for the driver can be found either with the driver or on the homepage for the driver.
4. Go to the next screen, enter how many drivers are going to be in the box.
5. Select Closed or Vented.... unless you're a real guru you probably don't need to worry about 4th or 6th order bandpass.
6. You can go through the tabs and enter whatever parameters you like.

Remember, if your doing a ported box the tuning frequency is the frequency that you're trying to achieve. If you set it too low odds are the only way you'll reach it is by having a ridiculously big box, or with some massive ports that will cause huge delays and you won't get the nice crisp notes.

One trick to WinISD is if you need to change the units the values are in you can click them and it will change. The default values are usually non standard and the values you get with the sub are not in the same measurement.

Here's a few things you'll need to know:
The Box tab lets you enter the volume of the box, remember this is the interior displacement of the box, not exterior. It also lets you enter the tuning frequency.

The Vents tab lets you enter how many ports (vents) you are putting on the box, what diameter they should be (or you can enter your own) and how long you'll have to make it to get the above graph. Mach is a measure of windspeed (I think, not 100% sure, maybe someone else can verify).

Gain Tab
This shows how "loud' the speaker will be. Remember, every 3dB requires twice as much power to attain.

Group Delay
This tab combined with Gain are the two most important tabs. This shows the shortest interval the speaker is capable of producing the note at a given frequency for. Remember if you have quick hitting bass notes (bass drum typically) you'll want a response time no greater than 7ms. Otherwise they'll begin sounding like one long note.

That's about all I can think of. I tried not to get too detailed. I was thinking maybe if I clean this up a bit it might be a worthwhile sticky.