Well I entered my first sound off (at Biggenden Auto Spectacular) today and i got 135.9 i'm pretty happy the result considering it was my first time ever and my setup

The results were:
1st Run: 135.9db
2nd Run: 134.8db
Final: 135.3db

And I came away with 3rd place in super stock (20" and less)

2nd run i forgot to put my revs up... and in between the 1st, 2nd and 3rd runs i had the car all shut up so it has a bit hot in the cabin... so it may have let my figures down a bit maybe, i dunno... never done it before so i dunno all the tricks of the trade

The two that beat me had more surface area, 2nd bloke had 2 10"s (had borrowed subs and amps, and had ported boxes) and the winner had 1 fusion 15" (car was a sound car with 2 15"s but he disconnect one to run in the super stock class), and both had been to multiple SPL comps, and both of them only got 137.x (Can't remember the exact figures), so i wasn't far behind, so i am very happy with my results.

Anyway to the point of this post... I'm wondering if i'd get much better results converting my box to ported... (it its big enough?)

Dimensions (all are quoted internal dimensions):
Base 280mm
Top 110mm
Width 815mm
Height 310mm

So Volume = 0.5(110+280) x 310 x 815
= 49266750mm3
= 49.26675 Litres
= 1.73983886 cubic foot

Kicker's compact ported box (the smallest recommended ported dimensions) is 1.75cu ft + port (does that mean the port is not included in the volume?) for the slot port they say: 2.5x13.25" port, 22.5" long

Could i run a round port (using PVC or simular?) and what dimensions if so? would my box be big enough?

If i was to convert it to ported, how much of an increase in dB could i expect? (everything else the same)

[quote name='birdd' date='Aug 12 2006, 10:44 AM' post='698390']
both had been to multiple SPL comps, and both of them only got 157.x (Can't remember the exact figures), so i wasn't far behind, so i am very happy with my results.

was it 157 db or 137 db that is a big different.

porting WOULD make it louder, but after port displacement, say a 4" round port, tuned to say 37hz, and sub displacement, you would be looking at around 1.4cuft net. inverting the sub would help, but when it comes down to it, a bigger box will do you a lot more justice.

Sorry i don't mean to cripple your first effort or anything but you said the other 2 winners got 157.x and you weren't far off... Was that a typo at all? I'm agreeing with wazzab4... 20 decibels is a kind of well.... very big difference . Regardless, best of luck with ya setup mate, i'm getting ready to put my first entry in in a few months

Yeah it was meant to be 137.x db opps damn typo

Yeah so the box probably isn't big enough to just "wack a port in" is it? I don't really want to build a bigger box for two reasons, i can't be bother building another box for this car (I want to upgrade soonish (end of the year or so)), and I've already taken a fair bit of room, and i want to keep as much boot space as possible...

I'd just build a new box, about 2.5 cubes.

I ran a 12" L7 a while back, of a D2 @ 2 ohms busted out a 141.9 on Lab before we pushed it a little too hard.. oops:)

Michael Would you put a port of any type in it.
slot or tube port or leave it sealed.

external porting no good?

would probably look dodgy... I'd want to put the port on across the top if i was going to do that... if you can show or tell me if its possible to do a good looking external port i'd consider it... I want to also do my boot up to be a bit showy so i don't want to have it looking dodgy

You'd probably want to use a slot port as it will make better use of the available surface area on the box, problem with porting small boxes is that your port lengths get longer in order to achieve the same tuning.

OR.......use and external 4" aeroport about 7" long and screw it to the outside of the box, the tune will be the same and u don't lose any box volume (should tune to around 45 hz, probably a little higher once u allow for the flaring of the port on both ends.)





Below, an example of an aeroport, not entirely out of the box, but I'd say it has about 3" inside.

(No its not mine although it brings back memories of when I had my 9910s in the barina)

....cool....i was right with the external porting

(barina picture opened up).......wtf?!?!?....is that amp painted?!?!....yuk lol

That looks dodge-city

exactly what i was thinking I think the only solution would be to build a new box... and i'm not really wanting to do that

if your planning on not using the box again... you might as well just cut a 4" round hole and then chuck a pvc pipe in it and see what numbers it does... you would be better off making a ported box... i'd say 2.5cuft b4 port and sub displacement.
and maybe even try sub up port back in your car.

A lick of paint and that port would look schmick

That's a nice install!

No disrespect to Enzo it was a great idea

What size box and port size where you using, and how much power were you feeding the sub?

I'm feeding mine 700WRMS @ 2 ohms. The sub is 750WRMS, 1500W Max... How much power could i safely feed it?

those l7s are good for about 1000wrms i think iirc

I ran mine in 2.5cubes total, with approx 55sq" of port area.

Car was a 97 Kia Mentor, box and port bot firing backwards.

The box was only as wide as the woofer plus the port and about an extra 50mm.

used a 2kg tin of fibreglass to seal it inside and out, that box was a tank.

Was running the woofer of a single D2 @ 2ohm, they're rated to do 2000rms at 2 ohm.

There was a member on here named Tarwah, she got to 148s with a single L7 also, same kinda deal, 2.5ish cubes, a D2 and an N13 pulsar.

D2??? do you mean 2ohm+2ohm???? or is that model of the L7 or something?

a D2 is an amplifier

^^ what he said, made by Earthquake and for quite awhile was the "it" amp for db draggers around the world, packs a shi.t load of power for its size making it very versatile.

However in recent times there has been alot of old unbstable D2s going around smoking at random

post deleted, im a tired idiot who forgot his maths