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RogerWilco
12-26-2004, 11:36 PM
Just went to home depot and bought 3 pieces of 4x8 3/4 mdf. First off i was in a hurry because they closed in 20 mins, secondly it was 0 degrees out but... I didnt bother to see if they'd fit in my vehicle :) It was an adventure getting them home... But it happened!

Anyways i need to build a box, i've never built a sealed before let alone a ported.. but i've gotten the idea that a sealed would make my sub sound like garbage. Its a audiobahn 15" (800 rms). One question i've had for awhile, this is probaly i really simple question but.. how do you tune your ports?

So is there anything inparticular i need to watchout for when im building a ported box? If not i'll just follow a tutorial somewhere and hope all goes well!

Damaso87
12-26-2004, 11:56 PM
Quite the contrary, the sealed will make the sub sound more accurate...in a way. Oh, and, i dont know how much worse of a sound than garbage you could get with that sub...
To calculate tha port tuning, you have to incorporate the volume of the box to the volume and stuff, i dont know how to do it, i pay JMac to do it...but theres a tutorial stickied.

http://www.caraudio.com/vb/showthread.php?t=68635

IgnoreMe
12-26-2004, 11:59 PM
you can try my tutorial in my sig but jmac will just say its wrong. been workin fine for me though, even if its wrong it aint wrong by much.

RogerWilco
12-27-2004, 01:55 AM
i wasnt refering to having the sub be accurate, but just sound "good" (not SQ but SPL) obviously the SQ isnt good on bahn subs, but the SPL isnt bad. And i've heard that sealed boxes are bad for bahn subs which makes sense. So i was going to give it a ported enclosure purely for SPL not SQ. I dont care if it lags slightly behind the beat, i realize the response is not going to be very tight. Thanks!

jellyfish420
12-27-2004, 02:01 AM
3 sheets of mdf huh? i've never used more than one before.

req
12-27-2004, 02:09 AM
i wasnt refering to having the sub be accurate, but just sound "good"

lol, because everyone else thinks "sound good" means accurate bass response - be a little more descriptive next time :thumbsup:


(not SQ but SPL) obviously the SQ isnt good on bahn subs, but the SPL isnt bad.

yea, they can get quite loud, but the response and accuracy (the "sound-good"ness is bad)


And i've heard that sealed boxes are bad for bahn subs

since when does a sub sound worse in a sealed application? as long as the box is made for the speaker - or, not prefab - all sealed boxes *in theroy* should sound better (you know, more response and accuracy)


which makes sense. So i was going to give it a ported enclosure purely for SPL not SQ. I dont care if it lags slightly behind the beat, i realize the response is not going to be very tight. Thanks!

no, it will lagg behind the beat, and most likely it wont sound good doing it eaither. however, that is purely subjective. if you are moving from roadgear prefab to audiobahn custom - you should gain some sq... wow is that possible?

but, you can make that sub sound *reasonably* good if you build the perfect box for it. do yourself a favor, pay someone $10, and they will send you all the calcualtions & dimnesions of all the cuts and direct you on how to build your new box. maybe in the future when you practice some more, you can get er'on.

or you could try and build this folded horn box.

http://www.sounddomain.com/memberpage/698298

it would get loud as fcuk for sure, even though it wasnt made for the abahn, it was made for a RE SE 15. but yea, that should make your colon tickle.

RogerWilco
12-27-2004, 08:49 PM
well as much as i would like to build that folded horn box, there would be some problems with it. One i think the rms handling of my abahn sub would drop enough to were my amp would overpower it, two its way too giant, and three its awfuly complex for my first box. Thanks though, it'd would be sweet. Seeing as i have 3 sheets of mdf, i suppose i could try and build it later.

http://img155.exs.cx/img155/8586/subbox15abahn4zq.png

Heres an example of what im going to make, it looks pretty simple, and should fit my needs fine. Anyone have any comments or corrections ? I think i've got everything right but its very possible that its entirely wrong.
Specs:
Volume - 4 ft^3 (2x2x1 or someother combo)
total air space - 3.5 ft^3
Port size - 4 x 11.25 inches
Port Velocity - 11.97
Both tuned to 45 hz
Sub displacement is .25 ft^3

just realized this suggested that i tune it to 45 hz. Well thats going to need to be changed....
Would there be a problem with just tuning it to oh say, 32hz rather than 45? or would it be better just to redesign the entire box ?