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View Full Version : 4th order bandpass question



Buck
11-20-2009, 02:43 PM
How much larger can the ported chamber be than normal?

or better yet, can it be larger?

marcotheclepto
11-21-2009, 02:09 AM
How much larger can the ported chamber be than normal?

or better yet, can it be larger?

what do you mean? vague question

altoncustomtech
11-21-2009, 10:35 AM
How much larger can the ported chamber be than normal?

or better yet, can it be larger?


You really need to study on the theory and design of these enclosures before attempting to build one without any plans... Just out of idle curiosity, why so interested in Bandpass??? I heard a long time ago it was as easy as putting the recommended sealed and ported enclosures for the sub together, and the guy who tried it failed miserably, LOL..... as i stated in another post, I've built a few and they turned out just fine, a guy still has one of them and after around 10 years it still sounds fine.... but that one as well as the others were built according to the manufacturers designs which made it realy easy..... designing one from scratch is not an easy thing to do.... I hope some of the guys on here that know may chime in and help you out with it, while it's not a type of enclosure that I prefer to listen to, they can be fun!

Buck
11-22-2009, 09:57 PM
You really need to study on the theory and design of these enclosures before attempting to build one without any plans... Just out of idle curiosity, why so interested in Bandpass??? I heard a long time ago it was as easy as putting the recommended sealed and ported enclosures for the sub together, and the guy who tried it failed miserably, LOL..... as i stated in another post, I've built a few and they turned out just fine, a guy still has one of them and after around 10 years it still sounds fine.... but that one as well as the others were built according to the manufacturers designs which made it realy easy..... designing one from scratch is not an easy thing to do.... I hope some of the guys on here that know may chime in and help you out with it, while it's not a type of enclosure that I prefer to listen to, they can be fun!

I've studied it to the best of my ability :). I do stuff with car audio for fun. Especially designing and building boxes. My friend has a couple of 8"s that he has nothing to do with, so I was going to mess around and try to build a bandpass box for them, just to see what it will turn out like.

galacticmonkey
11-23-2009, 02:10 AM
I could experiment with a design or two if you want to build it.

Buck
11-23-2009, 09:33 AM
I could experiment with a design or two if you want to build it.

Could we do a tag team :naughty:

Lol, jk but I want to know how you get your specs.

rmzsuzuki89
11-23-2009, 09:41 AM
I think it's usually a 3:1 ratio with the rear vs front chambers. I'm no expert though, just what I've seen and heard in most instances.

Buck
11-23-2009, 09:54 AM
How big would the front chamber be for two 9kv.2s? (8"s)

CLNFREAK
11-23-2009, 09:56 AM
http://i256.photobucket.com/albums/hh198/YALEROYNOT/0728091706.jpg

http://i256.photobucket.com/albums/hh198/YALEROYNOT/downsized_0622091837.jpg

this is mine I built and designed, I will have to find my build notes, the 3:1 sounds close. the out side dim of mine is 36x30x14 the port is tuned to around 38 hz. right now I have 300 watts going to it and it pounds, I have a jbl 1400.1 (1200 @ 4 ohm )that should be in there this week so it should be quite louder LOL

rmzsuzuki89
11-23-2009, 10:00 AM
How big would the front chamber be for two 9kv.2s? (8"s)

I've never used those, mor am I familiar with them at all lol. What power are you gonna use, and do you know the reccomended sealed volume for them?




this is mine I built and designed, I will have to find my build notes, the 3:1 sounds close. the out side dim of mine is 36x30x14 the port is tuned to around 38 hz. right now I have 300 watts going to it and it pounds, I have a jbl 1400.1 (1200 @ 4 ohm )that should be in there this week so it should be quite louder LOL

Holy low tuning for a 4th.:eek: I bet it anialates the lows.:D

Buck
11-23-2009, 10:03 AM
I was thinking about tuning to 42 hz based off the little I know.

Here is the sub:

http://www.edesignaudio.com/product_info.php?t=2&products_id=29

Buck
11-23-2009, 11:19 AM
bump

Buck
11-23-2009, 01:26 PM
bump

Buck
11-23-2009, 02:05 PM
bump

DNick454
11-23-2009, 02:13 PM
Best would be to upload the exact T/S specs of the driver into WinISD and fiddle around with all the volumes and tuning and have overlay the transient response over a typical ported and sealed box for reference. Just **** around with it until you get a transient response that models up nicely and then go about sketching a design that meets those specifications. Let me know if you want any help :)

galacticmonkey
11-23-2009, 02:14 PM
To get the specs of a bandpass, I just use my judgement. Theres no real equation, or calculator or graph I use... I just kinda guestimate. Havent had any problems so far.

Buck
11-23-2009, 02:17 PM
Best would be to upload the exact T/S specs of the driver into WinISD and fiddle around with all the volumes and tuning and have overlay the transient response over a typical ported and sealed box for reference. Just **** around with it until you get a transient response that models up nicely and then go about sketching a design that meets those specifications. Let me know if you want any help :)

That's what I've been doing for a little while. What I was trying to ask is if the ported chamber in a 4th order be slightly larger than the recommended box?

Buck
11-23-2009, 02:18 PM
To get the specs of a bandpass, I just use my judgement. Theres no real equation, or calculator or graph I use... I just kinda guestimate. Havent had any problems so far.

How do you guess what tuning it should be at?

galacticmonkey
11-23-2009, 02:22 PM
Depends on the application and the type of sound you want.

Buck
11-23-2009, 02:35 PM
Depends on the application and the type of sound you want.

I know that :)

With a sealed box holding air in, I would think the lower end would be extended down to a lower frequency because the sub has more control.

Buck
11-23-2009, 03:03 PM
The biggest question for me is what size to make the box.

Buck
11-23-2009, 03:30 PM
The biggest question for me is what size to make the box.

What this guy said.

Buck
11-23-2009, 07:42 PM
bump

galacticmonkey
11-23-2009, 07:51 PM
For the most part a bigger sealed chamber will drop lower.

Do you just want me to design you something?

mobeious
11-23-2009, 08:06 PM
The biggest question for me is what size to make the box.

really has alot to do with the vas of the subwoofer used as well as the Fs and xmax .. typicaly the larger the ported portion the more efficiant the box is but it is also is going to have more of a peak vs the smaller the ported section is the flatter the responce will be over a givin set of freq... if u would like a box designed click the contact button in my sig

Buck
11-23-2009, 08:08 PM
For the most part a bigger sealed chamber will drop lower.

Do you just want me to design you something?

Nope. I just need a little guidance.

Just messing around on winisd I have .7 cubes sealed and 1.5 cubes ported, tuned to about 40 hz. Looks fairly good on the graph.

mobeious
11-23-2009, 08:08 PM
Nope. I just need a little guidance.

Just messing around on winisd I have .7 cubes sealed and 1.5 cubes ported, tuned to about 40 hz. Looks fairly good on the graph.

winisd doesnt do crap for bandpasses

galacticmonkey
11-23-2009, 08:11 PM
Never tried WinISD, but I know BBP is way off for bandpasses. And 40hz will be a low end monster and most likely wont do much for high bass.

Try 1 cube sealed, 2 cubes ported. Go for around 40in^ of port, tune to 45hz. That would be great for daily for a 12.

mobeious
11-23-2009, 08:17 PM
i believe the sub he is refering to is a 8"

per 8 i would do .3 sealed into .4 ported 48hz with around 10sq of port that should give u a fairly good bandwidth

Buck
11-23-2009, 08:17 PM
winisd doesnt do crap for bandpasses

:crap:


Never tried WinISD, but I know BBP is way off for bandpasses. And 40hz will be a low end monster and most likely wont do much for high bass.

Try 1 cube sealed, 2 cubes ported. Go for around 40in^ of port, tune to 45hz. That would be great for daily for a 12.

I have trouble understand how I can go that big in the sealed portion.

Buck
11-23-2009, 08:18 PM
i believe the sub he is refering to is a 8"

per 8 i would do .3 sealed into .4 ported 48hz with around 10sq of port that should give u a fairly good bandwidth

It's 2 ed 9kv.2s

http://www.edesignaudio.com/product_info.php?t=2&products_id=29

mobeious
11-23-2009, 08:19 PM
correct thats per 8 so it would be .6 into .8 with 20sq

Buck
11-23-2009, 08:21 PM
correct thats per 8 so it would be .6 into .8 with 20sq

Well ****, why is the ported chamber so small?

mobeious
11-23-2009, 08:22 PM
its not ,, if u want a bigger peak then u can up the ported section but u will loose some bandwidth

Buck
11-24-2009, 11:16 AM
Post cubes and frequency I should use :)

I've been told like 3 different sizes. My buddy just gave me the 8"s today. These little things have some nice excursion compared to most 8"s.

Buck
11-24-2009, 11:55 AM
its not ,, if u want a bigger peak then u can up the ported section but u will loose some bandwidth

I'm looking to play 28hz to about 55 hz. That's really all I want to hear out of my substage.

mobeious
11-24-2009, 03:03 PM
ur asking alot of a pair of 8's to play 28hz with authority lol .. 48hz would give u a -3db around 30hz

mbrooky
11-24-2009, 03:33 PM
correct thats per 8 so it would be .6 into .8 with 20sq

just build it already OP...he knows what he's talkin bout...:D
and do a build log as well:p:

mobeious what do you think about a nightshade 18...2 cu sealed/4 cu ported @48hz?

Buck
11-24-2009, 03:46 PM
ur asking alot of a pair of 8's to play 28hz with authority lol .. 48hz would give u a -3db around 30hz

Alrighty. I forgot I was talking about 8"s. I get carried away.


just build it already OP...he knows what he's talkin bout...:D
and do a build log as well:p:

mobeious what do you think about a nightshade 18...2 cu sealed/4 cu ported @48hz?

Hopefully it'll turn out good.

mobeious
11-24-2009, 04:30 PM
well 2 cubes might be a bit big .. the nightshade has a fs of 41ish hz so u really want to dampen anything under that so considering how much power u are going to have u could go 1.25-1.75 and then if u want high output then the ported section should be in the 3cube area and for a less peaky box around 2-2.5 and i would tune around 45hz if u want a low end monster


edit cancel that i thought we were talkin 15 lol

tez4life
11-24-2009, 06:18 PM
well 2 cubes might be a bit big .. the nightshade has a fs of 41ish hz so u really want to dampen anything under that so considering how much power u are going to have u could go 1.25-1.75 and then if u want high output then the ported section should be in the 3cube area and for a less peaky box around 2-2.5 and i would tune around 45hz if u want a low end monster


Very interesting, hmmm......

mbrooky
11-24-2009, 06:51 PM
well 2 cubes might be a bit big .. the nightshade has a fs of 41ish hz so u really want to dampen anything under that so considering how much power u are going to have u could go 1.25-1.75 and then if u want high output then the ported section should be in the 3cube area and for a less peaky box around 2-2.5 and i would tune around 45hz if u want a low end monster


edit cancel that i thought we were talkin 15 lol

so how about 18 specs on 3500wrms :p:

mobeious
11-24-2009, 07:18 PM
i would need the T/S of the woofer if u want to get with me in PM i can help ya out just click the contact link in my sig

CLNFREAK
11-25-2009, 07:20 PM
I've never used those, mor am I familiar with them at all lol. What power are you gonna use, and do you know the reccomended sealed volume for them?



Holy low tuning for a 4th.:eek: I bet it anialates the lows.:D

YE it hits real low in a evil kinda way :evil::scared::omg::censored: but sounds great I love it :D

supermaxx123
11-25-2009, 10:48 PM
I wanna see/hear this :)

Buck
12-01-2009, 02:34 PM
The Qts is .30

power-fanatic07
05-26-2010, 08:01 PM
mobeious, clear pm's :)

AARON30
05-26-2010, 09:00 PM
i have a 12" powerbass 3xl that takes 850rms that i wanted to do this with, porting it through my backseat...is it okay to put a speaker made for a ported box in a bandpass like this?

AARON30
05-26-2010, 10:46 PM
Never tried WinISD, but I know BBP is way off for bandpasses. And 40hz will be a low end monster and most likely wont do much for high bass.

Try 1 cube sealed, 2 cubes ported. Go for around 40in^ of port, tune to 45hz. That would be great for daily for a 12.

i wander if this would work for my 3xl sub?