what enclosure to use

[hoodlegend]

hi ive got a panasonic CJHD253 subwoofer. it just came with very light specifications. i was wondering if anyone can tell me what type of enclosure i should use and how big. can anyone please help me?

[vinnym86]

Originally Posted by hoodlegend

hi ive got a panasonic CJHD253 subwoofer. it just came with very light specifications. i was wondering if anyone can tell me what type of enclosure i should use and how big. can anyone please help me?

usually a qts of 4.0 and under is better suited for ported enclosures. I think that sub is under 1. i know there is a chapter on bcea1.com about enclosures, theres a calculater in there where u input some data and it recomends a box for you. still though, you can make w/e box u want really.

EDIT: ur qts is 0.37 Panasonic CJ-HD253

[sr20de4evr]

Originally Posted by vinnym86

usually a qts of 4.0 and under is better suited for ported enclosures.

that's .4, not 4

and that's only a suggestion, and it's only one of at least two. The other is the efficiency bandwidth product (EBP), it's the Fs/Qes
EBP <50 is sealed
EBP 50-90 is either
EBP >90 is ported


Most subs can be used in either, it really comes down to personal preference. With a decent sealed box you're going to get a relatively flat in-car response with just about any sub and no EQing. You aren't going to get a flat in-car response out of a ported or bandpass box unless you are purposefully shooting for that and have a shitload of room available (needs to be small and tuned very low, a small enclosure with a 15hz tune requires a HUGE port). Most ported boxes are going to give a large (~10dB) spike around the tuning frequency, if you like to have a small range of frequencies grossly overemphasized then a ported box is for you, if you like to have an even smaller range of frequencies overemphasized even worse then a bandpass box is for you.

[vinnym86]

Originally Posted by sr20de4evr

that's .4, not 4

my bad, i got mixed up somewhere

[hoodlegend]

cheers bro, that help me. but i don't have enough specifications to calulate the enclosure required. can you help me please?

[CBFryman]

Originally Posted by sr20de4evr

that's .4, not 4

and that's only a suggestion, and it's only one of at least two. The other is the efficiency bandwidth product (EBP), it's the Fs/Qes
EBP <50 is sealed
EBP 50-90 is either
EBP >90 is ported


Most subs can be used in either, it really comes down to personal preference. With a decent sealed box you're going to get a relatively flat in-car response with just about any sub and no EQing. You aren't going to get a flat in-car response out of a ported or bandpass box unless you are purposefully shooting for that and have a shitload of room available (needs to be small and tuned very low, a small enclosure with a 15hz tune requires a HUGE port). Most ported boxes are going to give a large (~10dB) spike around the tuning frequency, if you like to have a small range of frequencies grossly overemphasized then a ported box is for you, if you like to have an even smaller range of frequencies overemphasized even worse then a bandpass box is for you.

funny thing is i am pretty damn flat from 50Hz down to like 25Hz...(and dont tell me im not ive been on the mic and im pretty much +-3db from 30-50Hz and maybe about -4dB down to 25-27...which means i hover around 140dB)
which is a full octave.
my set up doesnt like to play over 50-60Hz so actually these "grossly over emphasized fequincys" which you are refering to that is rap music dont play well alot of times unless they drop low....which is why my set up carries so far (low frequincies travle further than higher frequincies though when driving away from an object the sound drops even lower so your ears loose sensitivity to the music, i know you knew that SR20 but some probably didnt or couldnt put a name to that phenomenon)
i need better midbass

[vinnym86]

Originally Posted by hoodlegend

cheers bro, that help me. but i don't have enough specifications to calulate the enclosure required. can you help me please?

I can't find the technical specs to that sub anywhere, its not even on panasonic's website. try contacting your retailer, or maybe even panasonic themselves.
If you do get ur hands on some specs, here is a site that might help you out building your box:
http://www.carstereo.com/help/Articles.cfm

[sr20de4evr]

Originally Posted by CBFryman

funny thing is i am pretty damn flat from 50Hz down to like 25Hz...(and dont tell me im not ive been on the mic and im pretty much +-3db from 30-50Hz

Staying within a 6dB window in less than an octave is not flat....staying within a 1-2dB window for 2+ octaves is flat, and most decent subs in a reasonably thought-out sealed box will give you that.

[Mannyb18b]

Your XXX comps dont give you enough midbass???

[sr20de4evr]

Originally Posted by Mannyb18b

Your XXX comps dont give you enough midbass???

RE comps, not XXX

the XXX comps aren't even available yet

[Mannyb18b]

Ya, but I thought CB bought the XXX mids and went active........

[CBFryman]

that was noah

[Mannyb18b]

oh, hmm... well is the loss of midbass that bad cbfry? im thinkin of getting a pair, but not so sure now. How do they keep up with the 18 cause i will have a similiar setup

[CBFryman]

its isnt that the RE'sare bad, its that i have them getitng maybe 15-20w on a cheap sony amp and i have 0 deadaning in my doors and that really XXX's or Koda's are all there are that can keep up with an Ava18.
i can turn my bass knob down to about 1/4 and the whole system sounds quite nice actually. rock, country, anything...