what to expect from box change-

[builthatch]

currently, i am running one alpine type-r 12" pushed by bridged second 2 channels of an alpine pdx 4.150. it sound phenominal; very tight and deep, however, i am curious exactly what i can expect if i change from my 1.0' sealed box to this http://www.crutchfield.com/S-s...712SS

i figured since i'm on the lower end of wattage for this woofer (despite a superior quality amplifier), i might gain some efficiency using the ported box and it'd be alot more 'boomy', but i've not played with this stuff in a long time so i don't know what's what anymore.

 

[aaronc7]

ported...will be 'louder' and boomier. better for rap and stuff like that, but sealed is the best for rock or stuff with tight fast bass (IMO)

 

[Excido]

The difference depends on your tuning and size of the enclosure. Porting, with a large enough enclosure, will go much lower and stay very smooth in it's response. However, since the boxes usually aren't very large the end result becomes a large spike just before the response falls, causing that "boomy" sound. This is known as having a high Qtc. The sealed will roll of faster but will usually be more "tight", however less efficient.

Personally I like sealed subs when a large enclosure isn't a viable option, however with a properly designed enclosure a ported sub can sound just as good as a sealed sub, but go lower.

Hope this helps.

 

[El Ropo]

Anyone who has experience with type Rs will tell you that 300 watts to one in a sealed box isn't enough power. Many are running type Rs with over twice the rated RMS. Many people have also claimed they couldn't get their type R to sound right till they upped the power.

Ported would be a better solution. But honestly, you need more power.

Oh, and FWIW, a huge majority of sealed boxes will go lower than ported boxes, since the frequencies below the tuning frequency of said ported box will be sharply attenuated.

Example, you have a properly designed sealed box, and play a 25HZ test tone, you will hear it just fine. Play the same 25Hz test tone in a ported box that's tuned to 35-40Hz, and one of two things are going to happen. The first would be that you have a properly setup SSF (sub sonic filter) and you don't hear the note at all. Secondly would be no SSF at all, and you completely unload your sub below tuning frequency, and it self destructs right before your eyes. Now if you could tune your ported box to 25Hz, then you would hear that note, but the size of the box becomes quite large with that sort of tuning.

Ported boxes are generally about 3db louder than sealed. So they go louder, but not lower.

 

[Excido]

Example, you have a properly designed sealed box, and play a 25HZ test tone, you will hear it just fine. Play the same 25Hz test tone in a ported box that's tuned to 35-40Hz, and one of two things are going to happen. The first would be that you have a properly setup SSF (sub sonic filter) and you don't hear the note at all. Secondly would be no SSF at all, and you completely unload your sub below tuning frequency, and it self destructs right before your eyes. Now if you could tune your ported box to 25Hz, then you would hear that note, but the size of the box becomes quite large with that sort of tuning.

Ported boxes are generally about 3db louder than sealed. So they go louder, but not lower.

Sorry, should have mentioned that part, you're completely right. Play a tone below the tuning point of ported box and you'll destroy that driver, and due to size limitations the port tuning tends to be high in cars. The ported systems have the ability to go much lower with a sufficiently large box (which can be big).