Need help with 2 12" spl box!!!

[Wizzy]

Hi guys. I am trying to build my first spl box for 2 12" Ground Zero gzrw30spl.

Problem is that i have no ideea how to do a burp box for score. What frequency do i have to tune? How many liters? What port size? How to wire the coils? Where do i place the port ( sided, centered between the woofers ) ? etc...

What kind of port should i use? Slotport or aero? I would love to use one or 2 aeros but i have no ideea how to calculate them...

Car is a Ford Focus MK2 2007 4 doors hatchback.

Sub has to be in the trunk, subs facing up with port also up i think it will be better, if not please tell me.

I have a 3000 w rms @ 1 ohm amplifier for those 2.

Specs of the subs:

Model GZRW 30SPL

Diameter 300 mm / 12"

Mounting diameter 281 mm / 11.06"

Mounting depth 150 mm / 5.91"

Voice coil 63 mm Runddraht / 2.5" Round wire

Cone Verstärktes Papier / Reinforced paper

Power Handling 1000 W SPL Power

Impedance 2 x 2 Ohm

SPL 92 dB

Xmax 20 mm / 0.8"

Fs 33 Hz

Qts 0.36

Qms 5.97

Qes 0.38

Bl tesla-m 18

Vas 52 L / 1.82 cu.ft.

Box recommendation vented 55 Liter / 1.94 cu.ft. - Rohr / Tube 2 x Ø 8 cm / 3.15" - L = 20 cm / 8"

Box recommendation sealed 20 - 28 Liter / 0.7 - 1.0 cu.ft.

Please help me with a spl box design for those 2 woofers.

Can a do a box with a changeable port? I want to use it both for spl run and daily music if possible:D

Max dimensions would be 20" height x 35" wide x 16" widith.

Thanks in advance:)

[Wizzy]

Nobody? At least any advice is helpfull... Joe X maybe you can help me?

[jarrius]

I can't help but it may be a day befor some one who can help replays. Give it some time bro and people will help

[Wizzy]

ok thanks for the advice. im not in a rush altough im very excited about bulding the box because in 5 days i have a contest in my country and if i finish my system i will participate:D

[Chris Hammer]

You have to figure out your vehicles peak. IIRC reading about ways to find it a while ago people would use sealed box and find the peak in output, using test tones. You can do it by ear, but you could be a little off. When you find the peak build for your peak. Alsoyour enclosure is going to be based on more then tuning, how much power are you running, are you burping or going for high score on music? What competition and class are you competing? WHat are the limitations in the class?

If you use aero ports you could do a interchangeable port easier, but if you dont have access to them you can do a square port out of MDF, and make it removeable to change lengths whenever you want.

There are some real knowledgeable guys on here, there is a thread on here about getting the most out of your setup where the original poster tried a bunch of different things on the same enclosure, kerfs, 45's aeros, coating, position etc.

[Nightshade]

I don't know how much different the euro focus is compared to the american one but I can tell you the best configuration is woofers up and port firing towards the drivers side of the car. Everything up does not work well at all. I have about six years experience with the american zx3 and I was the loudest unwalled zx3 with all the equipment in the hatch in the USA. I am fairly lazy typing on my tablet PC at the moment but you can pm me with questions and I will answer them later from my desktop.

[Wizzy]

Limits in my class are 4000 rms, 2 batteries, stock alternator, 1 run of awg 0. backseats can be folded.

So the best response i can get in this focus is with subs up and port firing drivers seat?

I will run around 2200 watts at 2 ohms on those 2 12".

At the measure i will burp tones.

From what i remember my car's peak is 55 56 hz.

I dont know nothing about aero ports.

[Wizzy]

Nobody nothing?

[john253a]

Idd try something like 4net 65-70sq" of port @50- 52hz

[alaskanzx5]

listen to nightshade great info on spl with the focus from him. he has done lots of testing in that car. peak is around 50-55hz of course thats all dependent on the direction of the box and the all around build.

my best (zx5) was with 2 t2d412 with a t1500.1bdcp. port and sub up port was on passenger side. could have been better if the port was on the driver side. did a 143 on a termlab with that and a 146 on an audio control. that was all before i started talking with nightshade. if i would have talked with him before hand i would have kept my 2 12s and tried playing around with new boxes for them. no i have 2 t2d415 that im doing a sub up port up build. cant do sub up port to driver side and still have the volume needed with the seat being able to latch and everything in the trunk under the window line.