VW Citi Golf Mk1 low frequency box build

[realsoundillusion]

Hi Guys/Gals,

Hope you are all doing really well, i've decided to try a low freq box. Not too low though not sure how much battery power i will need. I upgraded my alternator to 300amp. Still running my HD8000 2ohm stable subs will be wired in series giving me a 2ohm load, two power 0 Gauge power cables coming from the alternator to the rear battery, two more power cables from the front battery to the rear battery, four positives to the amp fro the rear battery 1m lengths. The same goes for ground. Now I'm no guru thus I am posting and asking advise. Subs are SA12 D2's.

What do you think of the box. the box will fit into the trunk with the battery and amp mounted to the floor in the trunk, subs firing up with port firing up.

Name:
Type: Standard one-way driver
No. of Drivers = 2
Mounting = Standard
Wiring = Series
Dual voice coils = separate
Fs = 33.71 Hz
Qms = 5.34
Vas = 21.21 liters
Cms = 5.34 mm/N
Mms = 4.174 g
Rms = 0.166 kg/s
P-Dia = 82.06 mm
Sd = 52.88 sq.cm
Qes = 0.52
Re = 4.57 ohms
Le = 3.4 mH
Z = 0.5 ohm
BL = 21.64 Tm
Pe = 600 watts
Qts = 0.52
1-W SPL = 83.21 dB
-----------------------------------------
Box Properties
Name:
Type: Vented Box
Shape: Prism, square
Vb = 128.2 liters
Fb = 46.01 Hz
F3 = 40.08 Hz
Fill = minimal
No. of Vents = 1
Vent shape = round
Vent ends = two flared
Dv = 203 mm
Lv = 195 mm

[realsoundillusion]

Not sure if nobody wants to comment or if no-one is willing to assist with advise.

[Joe X]

Your box is tuned to 46Hz and is about 4.5 cubic feet net, the only thing I can't figure out is what you call low frequency, around here low frequency is considered mid to upper 20s. There are many burp SPL competition boxes setup like what you plan to do.

[realsoundillusion]

Joe X, thanks a million you are a star, this means you are telling me that my box is more aimed at SPL as is. What i am afraid of doing is going too low like the mid 20's and not having sufficient power and cause damage to my amp or subs.

I will design another box to the mid 30's would that be ideal?

[Aj11]

going to low really isn't a power issue. you will lose the upper end bass tho. 40/60hz will be less. you should try a tune around 33hz. with a good size box with a low q you can play into the upper 20hz area and still play in the upper mid 40shz with authority!

but 46hz is imo way to high!

[Joe X]

BTW OP what are you doing with a 300A alt, dual batteries and a 8K amp for powering 2 SA-12s?

[realsoundillusion]

Joe X, reason for the Alternator upgrade was because i wasnt getting sufficient charge from my 65amp alternator. The car is actually built for SPL but i'm looking to try what you guys are managing, playing low and still able to do a good 150+ SPL in the same box, i wont be powering the SA12's for long will be slotting in a pair of NS v3's. so the sooner i get the power issue sorted the better.

[realsoundillusion]

going to low really isn't a power issue. you will lose the upper end bass tho. 40/60hz will be less. you should try a tune around 33hz. with a good size box with a low q you can play into the upper 20hz area and still play in the upper mid 40shz with authority!

but 46hz is imo way to high!

When you say tune around 33Hz do you want me to tune the Box at 33hz? Sorry box building is relatively new to me.

[Joe X]

Maybe you should seek in the mid to upper 30s for that balance, in any case it would be best to build a removable port, really with 2 sa-12s will be rather tough to get 150 and more so with reasonable musicality, pretty sure you can get it done with higher end series subs but you are going to need to work hard on that box, make really sure you flare those port ends properly. Also since you are already well invested think on some cool deadening job too if you have not done so already, best of luck.