Help guru (Glasswolf)

 

New member
Username: Alvingo

Post Number: 1
Registered: Aug-05
Hi! Im new here and I was wondering if anyone can give me some tips on how to built a box. I want deep bass and loud and i have a subwoofer 2 12 inches db312d crossfire that is 200rms, 350w maximum and dynamic power of 600w, and the db312d can provide a good punch in my previous setup in my car and now im looking forward to try deep and loud. I really appreciate if someone can help me. The amplifier is solid audio 1800rms @ 1ohms (a little overrated). The box that I made previously for this is vented as shown in its specs sheet.This is the parameters for this sub I dnt know, if it can handle for deep and loud application.

Driver description 12" Subwoofer, Dual Voice Coil
Mounting depth, in/mm 5.75/146
Woofer Outer Diameter, in/mm 12.5/318
Woofer Displacement, ft3/ltr .07/1.98
Impedance 4 ohm per coil
Nominal power handling (RMS) 200 watts
Maximum power handling (PE) 350 watts
Voice coil -- size 2", 4 layer
Resonance frequency (fs) 20.703Hz
Qts .366
Qes .397
VAS, ft./liter 4.74/134.394
X-max, in./mm .312/8
Efficiency (2.83V/1M) 86.6dB

The original box being given by crossfire is
large vented volume: 2.9/82.11
tune to 29Hz
Port 4" x 10.5"
25Hz 350 watts

This box is more on Punch bass when i tried it! Hoping for replies! :-)
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 9470
Registered: Dec-03
I'd probably go for about 2cu ft per sub after port and driver displacement (net vol) and use a slot vent tuned to around 28Hz. that'd hit very deeply and pretty hard with that power.
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 9471
Registered: Dec-03
if that's not what you're after, you may want to look at different subs
 

New member
Username: Alvingo

Post Number: 2
Registered: Aug-05
thanks for the reply :-) well, il try to make that! what if i used port would it make any difference? i already had a box 2.22 cuft and the port is 10.75. i can add the port length using elbow if its ok.um.. should i put fiber fill ? or not?
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 9484
Registered: Dec-03
won't need fiber fill, and shouldn't need to bend a 4" ID port for a 12" sub.
at 2.2cu ft and 28Hz you should be around 10" in length I think. if you shoot for 34Hz you'd be closer to 7" and that's easy to get a straight port at 4" diameter.
 

New member
Username: Alvingo

Post Number: 3
Registered: Aug-05
well when i computed winisd it says that the port would be around 16.81 inches. i dnt know if this is true or not. um... what software do yo used when computing boxes ? :-)
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 9518
Registered: Dec-03
a pencil and some paper

www.bcae1.com has some java scripted calculators for port lengths. so does www.the12volt.com they'll help confirm any of your calculations.

I may have been off. I was guessing at the lengths from memory, but I've rarely needed to bend a port, and when you do, you have a whole new slew of calculations to do to accomdate port velocity changes and tube lengths @ the turn.
its a bit of a pain really.
 

New member
Username: Alvingo

Post Number: 4
Registered: Aug-05
Yeah its really a pain! bending the port tube! i really dnt know how i can calculate when bending the port and maintaing the frequency! do you have any tips for that? :-)it will change the velocity and i dnt know if it sounds weird cz i never tried it.
 

Gold Member
Username: Glasswolf

Wisteria, Lane USA

Post Number: 9536
Registered: Dec-03
it's just a matter of calculating for the bend.. and if you're using PVC, you just use an elbow joint.
http://www.amazon.com/exec/obidos/ASIN/0071448470
or
http://www.amazon.com/exec/obidos/ASIN/0070580839
or
http://www.amazon.com/exec/obidos/ASIN/1882580338

any of these books will help you with those calculations.

for 34Hz with 2cu ft though, you're only at 11.7" with a 2ft^3 box so you don't need to bend anything
 

New member
Username: Alvingo

Post Number: 5
Registered: Aug-05
thanks for your help :-) your the best hehehe:-)
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