Aero port question

[Sweety]

go find a area of circle calculaor on the internet. plug in your port diameter take the result X length of port. take that time number of ports. if you have any port that will be external dont count that.

edit:

use the OD of the pvc

Thanks for that, maths isn't my strong point at all as you might tell. Grateful for your help so far guys

[Joe X]

Thanks for your help Joe X, my other option is to maybe build this enclosure I found on here http://www.stevemeadedesigns.com/board/topic/149509-box-design-help1st-time-box-builder/ only thing I'm not sure on is the port length as I normally do a double baffle on the front, would removing 3/4" off the end of the port wall to compensate for the extra added by a double baffle & add 45' bracing to all of the corners work? I was looking for a 34-35hz tuning point really as it's for my every day motor but a little lower at 33hz shouldn't make that much difference would it ?

By the way many thanks for your help with the plans I put up a while ago on a 3.5ft^3 enclosure for my Son, got it built & it sounds nice & he's really pleased with it

A couple of questions, what's the vehicle? what's the box dimensions that would be best in your situation?

[Sweety]

At the moment I own a Nissan Terrano 2 R20 (4x4) but it will hopefully be getting replaced later in the year for a Ford Mondeo estate or possibly the hatch back but i'me in the UK so model names for the Mondeo might be different where you are & I know the Terrano was never sold in the US or Canada. Max I would say is 30W X 14.5H X 14D

[Joe X]

This is an older sub likely aimed at sealed usage, with some tweaking it will work in ported but I wouldn't expect great or too loud, the good news is that your dimensions will work great and no round port is required, power: to sub rated, amp subsonic filter to 28Hz, minimum port clearance 2", figure is just an assembly guide:

[Sweety]

Many thanks again Joe X but noticed this is 2ft^3, I know JBL recommend 1.76ft^3 (50L) would my sub work ok in the larger volume enclosure? I can put up the full spec's for the sub if needed

[Joe X]

I have these:

JBL GT3 12
Fs = 28.2 Hz
Qms = 5.53
Vas = 100.4 liters
Cms = 254.5 µm/N
Mms = 125 g
Rms = 4.01 kg/s
Xmax = 10.92 mm
Xmech = 16.38 mm
P-Dia = 259 mm
Sd = 527 sq.cm
P-Vd = 0.576 liters
Qes = 0.6
Re = 3.14 ohms
Le = 1.15 mH
Z = 4 ohms
BL = 10.69 Tm
Pe = 225 watts
Qts = 0.54
no = 0.362 %
1-W SPL = 87.73 dB

You won't run into any issues since you are only running rated power to the sub, anyhow if you would wish to do the 50L box here is it:

[Sweety]

Thanks I wasn't sure if a large enclosure would cause issues or not, am I right in thinking the larger enclosure would most likely sound louder to the ear due to the larger volume

[Allen Lancos]

Check out Audible Engineering for aero , love mine!

[Joe X]

Thanks I wasn't sure if a large enclosure would cause issues or not, am I right in thinking the larger enclosure would most likely sound louder to the ear due to the larger volume

It's a small increase, you get a small gain on your lows for free, no side effects as long as you don't overpower.

[Sweety]

That's good to know & cheers, have no plans on changing the amp or the sub at the moment but when I do replace the sub i'll be getting a bigger amp anyway & use this JBL amp to power the front speakers