Ported Box?

[L|_|da]

I recently did a dual RE12 setup, NX400 amp, 200W, in a 3.2CUFT enclosure, sealed. im wondering if a ported box will make much difference, and if it will, how big to get that difference? and how hard is porting/tuning it? and help if much apreciated.

[sr20de4evr]

Well it will definitely make a big difference, the question is if you like that difference. To put it simply, you'll gain a lot of low end, it will be like putting in a 6-10dB bass boost at whatever frequency you tune the box at, and setting a very steep highpass filter about a half an octave below that, some people like it, some don't. I'm one that doesn't, because to me it sounds unnatural and....like crap. Ported boxes have their place, but that place is not in a car.

[/soapbox]

[L|_|da]

so basically, they cut down the RANGE of sound, but that range is LOUDER?

[PaulD]

yea, pretty much. And you have to use a steep filter below the port frequency because at frequencies much below that the box will look to the speaker as if it has a big hole in it (whick it does), and speaker will be unloaded ... similiar to free air.

[L|_|da]

steep filter? like fro mthe amp?

so below the tuned freq it sounds nasty / doesnt sound

[sr20de4evr]

When the sub starts to unload (about a half an octave below the tuning frequency), you'll have virtually no audible output and the sub's cone will be moving a LOT for a given amount of power, which means it will bottom out very easily. You need to set a highpass filter (aka subsonic filter) around the tuning frequency to keep this from happening.

[L|_|da]

ah, well do i have to get a new amp, or some sort of addon for the subsonic filter? the amp thats installed is an NX400. if i do what do i need, how would i go about setting up the sub filter?

[PaulD]

many eq's have them ..... they are real easy to set

[CBFryman]

SR20 is just an SQueer...

you dont have to worry about the roll off of ported enclosures in most daily apps because you will turn aroudn 30Hz generally and most music doesnt even have frequincies below 30Hz... and with the lower tunings your responce curve, though not as flat as sealed, isnt as peaky as they are telling you.

[Jeremy86]

I had a sealed box in my car and I thought that it was loud. I built my first ported box and it was amazing. I don't want to sound push offish or showoffish, but I talk to competitors and street beaters alike, and going from sealed to ported gives a 3db increase, which is about twice as loud as it was. Not trying to bash Sr20 at all, but basically a ported box, yes it seems to be louder at a certain frequency, I tune my boxes from 30-35hz which is really deep sounding. The thing with sealed boxes is it gives a flat response in all bass frequencies, which in some cases is better. Ported boxes I've always liked, you have to build the enclosure to what the sub likes, you can't expect a prefabricated one to sound good for your sub. Possible, but not probably the 'magic' box. It's not hard doing a ported box, it's more hard figuring out port length, how much port area you want, and the displacements of the port and sub. Using your TS parameters, you can design a box that your subs will like. If you think you're interested in it, let me know, I'd be glad to try to help.

[sr20de4evr]

Originally Posted by CBFryman

and with the lower tunings your responce curve, though not as flat as sealed, isnt as peaky as they are telling you.

anechoic it's not, but when you stick it in a car it is

[PaulD]

the problems is, the higher the order the more picky the box is to mistakes in volume and port calculations .... and that doesn't take in the cars response either

[Jeremy86]

Most cars if you tune around 30s will sound good. You need to worry about the resonant frequency in your car if you are looking to burp and compete. That's my opinion though.

[L|_|da]

i think ima gonna do this, but not for the RE12s, friend doesnt wan it louder. but i am getting a free 15" Kicker comp not solo baric. so im thinking about a 3-4 cube box, since i have the wood to make it(3/4" MDF) how much port area should i have, and should i use tubes? or square? and how do i calculate the port length?