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View Full Version : 4th order bandpass enclosure help



Audiopipe
10-31-2013, 09:49 PM
I'm trying to design a 4th order bandpass box for two audiopipe 15s but don't know which air space to use the subs I have call for 3cube ft each in a sealed box and 3.5 cubic ft each in a ported box. I have heard people say 2:1 ratio but is it off of total of 13 cubic ft or the seals or ported . I guess what I am asking is what cubic ft should I use for each sub sealed and what total cubic ft for the ported section and what size should the port be for say 32hz please help!!!

jeffdachef
10-31-2013, 09:59 PM
depends if your going for lows or music or spl. Also its 15s man thats always gonna take up room.

Audiopipe
10-31-2013, 10:23 PM
Spl n I know it's gonna take up room just how much total

Audiopipe
10-31-2013, 10:33 PM
How much total n how much per sealed sub

jeffdachef
10-31-2013, 11:05 PM
if its for spl you dont need that much in the sealed area if you plan on giving it a lot of power than recommended probably around 2.25 to 2.5 should be fine, leave more room for the ported section.

Audiopipe
10-31-2013, 11:07 PM
What should I do for ported area cubic ft wise

jeffdachef
10-31-2013, 11:09 PM
i've had good luck with the 2:1 ratio and the 2.5:1 ratios

Audiopipe
10-31-2013, 11:12 PM
So about 8 cubic ft for the port section total or am I totally off? I'm sorry if this sounds dumb but this is why I asked cause I have no clue with bandpass boxes

Beatin'
10-31-2013, 11:28 PM
from what I've seen, 4th's don't model well on winISD for example, when using a bigger ported chamber to sealed chamber ratio. They become too peaky.

jeffdachef
10-31-2013, 11:30 PM
i'd suggest sticking with ported or buy a design off of a professional on this site Buck ; can design you a box that'll get ultra loud.

you dont want to just guestimate with 4th orders you have to make sure a lot of variables are correct first.

Audiopipe
10-31-2013, 11:31 PM
I just need cubic feet answers for each sub sealed and the total for the ported side with the subs I'm using

jeffdachef
10-31-2013, 11:37 PM
from what I've seen, 4th's don't model well on winISD for example, when using a bigger ported chamber to sealed chamber ratio. They become too peaky.

they dont model well but they do turn out pretty flat in response with a decent bandwidth based on your tuning. It also really depends on how compatable the box works with your vehicle.

Audiopipe
10-31-2013, 11:48 PM
It's actually going in a trunk of a Benz but has a custom fiberglass rear deck with a big blow threw

jeffdachef
11-01-2013, 01:01 AM
It's actually going in a trunk of a Benz but has a custom fiberglass rear deck with a big blow threw

even if the trunk is really big, 2 15s 4th order in a trunk is kind of stretching it, unless you build it inside the trunk and take out the spare tire compartment. I wish you the best of luck though.
the 2:1 is a solid choice and gives you a pretty good handling and bandwidth. the 2.5 : 1 has the potential to be a lot more peaky depending on the tuning.

bbeljefe
11-01-2013, 01:15 AM
If you're going for SPL in a 4th order you don't want tuning that low. In the low to mid 40s would be better for both your goals and your subs, as they will not play well at low frequencies without a shite tone af air behind them.

If you want to do it right, I would recommend downloading WinISD Beta and modeling the subs in a number of different boxes. If you can find a curve you like on that program, then build it.

But just trying different volumes at random or relying on rules of thumb ratios that do not take into account the characteristics of the individual drivers is the reason why 4th and 6th order enclosures have the reputation of being hard to design.

Beatin'
11-01-2013, 01:20 AM
even if the trunk is really big, 2 15s 4th order in a trunk is kind of stretching it, unless you build it inside the trunk and take out the spare tire compartment. I wish you the best of luck though.
the 2:1 is a solid choice and gives you a pretty good handling and bandwidth. the 2.5 : 1 has the potential to be a lot more peaky depending on the tuning.

I too have a design for 2 bandpassed 15's in a trunk. It will not be a blow through however. Each sub will also get its own box due to a small trunk opening.

My setup will be 1.52cuf ported and 1.7cuf sealed after all displacements. 65hz tuning. It was modeled with my cars resonance frequency and cabin gain in mind. Can't wait to build it! wooooo hoooooo!

Buck
11-01-2013, 07:41 PM
You'd probably want to do a ported box. What car is it?

Audiopipe
11-02-2013, 01:28 AM
95 Mercedes c220

Audiopipe
11-02-2013, 03:34 AM
I've heard a lot of negative reactions across the board with a forth order in a trunk so I think I'm just gonna try to do a ported box with the port going threw my blow threw in my rear deck

jeffdachef
11-02-2013, 04:34 AM
I've heard a lot of negative reactions across the board with a forth order in a trunk so I think I'm just gonna try to do a ported box with the port going threw my blow threw in my rear deck

good call.

Audiopipe
11-02-2013, 06:24 AM
Should I build to spec or half a cube more I heard a little more is better then spec .... Any opinions ?

Beatin'
11-02-2013, 09:57 AM
good call.

How the hell is that a good call.

Ported setups need the cone to take care of upper bass frequencies and the port deals with the lower frequencies. A blow through ported will give you lows, and no highs, especially in a Benz.

I had the same issue designing a ported setup in a trunk with 2 15's. I found that I couldn't load the cones and the ports off of the same wall, so I chose to go with a 4th order instead.

UsAmpsFreak
11-02-2013, 09:59 AM
It's actually going in a trunk of a Benz but has a custom fiberglass rear deck with a big blow threw

Unless you are planning to take out the back seat so the port blows through a huge opening like that i wouldn't do it, all you're going to do regardless of how big the cutout on the rear deck is it's just going to greatly bottleneck the output from the box. 70-80% of the energy created will never leave the trunk.

jeffdachef
11-02-2013, 10:18 AM
How the hell is that a good call.

Ported setups need the cone to take care of upper bass frequencies and the port deals with the lower frequencies. A blow through ported will give you lows, and no highs, especially in a Benz.

I had the same issue designing a ported setup in a trunk with 2 15's. I found that I couldn't load the cones and the ports off of the same wall, so I chose to go with a 4th order instead.

its purely space wise, and the highs part, you can always tune a lil bit higher have the subs up and port to the rear to remedy the highs. its going to be difficult fitting the necessary space in his trunk, those subs might suffocate in a 4th order which can severely impact the sound.

Audiopipe
11-02-2013, 08:21 PM
The cut blow threw is only like 14x10 . I just would like how everyone else would is more output I have them in a prefab sealed now that's only 4.4 cube and seals rec is 3 per but I would love to hit more low then high but I want my cake and eat it to

RangerDangerV2
11-02-2013, 08:22 PM
just read my 4th order thread. loads of useful info