speaker box question

just curious here
i'm making a bandpass box for 2 10" subs, do i have to port the box?? i need 2 know asap as i am almost 100% done, just gotta touch up a bit of paint either make the port holes or not, mount the plexi, mount the black light and silicone screw holes

Can you provide more details or pics about your box?

What is the volume of the box?

What kind of speaker are you using?

Do you have the Thiele/small parameters for it?

Are you sure it's a bandpass box ? That's an enclosure inside an enclosure....

Are you building a regular sealed enclosure?

heres a quick drawing i did
its 12 inches high, 28 wide, and 14 deep
i'm using 2 Lanzar LXR Subs that are 200 watts RMS i believe

http://images.cardomain.com/member_images/11/web/467000-467999/467010_24_full.jpg

This may help you - http://www.diysubwoofers.org/bnd/4thorder.htm

you need atleast one port in one chamber

there needs to be a port between the outside world and the face of the speaker.

a 4th order bandpass has only this port, a 6th order has another port between the two chambers in the box

a bandpass box with no port would have trouble making any noise!

ok so i do need a port then?? where should i put it?? on the top where the face of the speaker is? or on the top where the magnet is??

ok so i do need a port then?? where should i put it?? on the top where the face of the speaker is? or on the top where the magnet is??

Usually the company who's subs you buy have 'suggestions' on their website about how large and how long the port needs to be, and also for suggestions on box sizes to be built in the first place.
But, where, how large, and how long your port is all depends on the over all volume of your box... or rather, the chamber you're going to put it in, because you can port either the face end or magnet end of the box.

Usually the company who's subs you buy have 'suggestions' on their website about how large and how long the port needs to be, and also for suggestions on box sizes to be built in the first place.
But, where, how large, and how long your port is all depends on the over all volume of your box... or rather, the chamber you're going to put it in, because you can port either the face end or magnet end of the box.


ahhh ok, well i've got 4 ports from the previous box i got these subs from
i think i might just use 1 and see what it sounds like

Here's a bandpass box i made a couple years back for 2 12" Cerwin Vega HED-DVC12 subs.

Two outside chambers are sealed, then there is one large chamber in the center with a large rectangle port to reduce port noise and for easy tuning.

http://files.automotiveforums.com/gallery/watermark.php?file=/500/32153boxdiagram.JPG

and the actual box..

http://files.automotiveforums.com/gallery/watermark.php?file=/500/32153box.JPG

this box was tuned to a peak at 45Hz because i like that low bass :D

nice setup!!
thats so crazy man

http://209.125.209.59/el//HBP210.jpg
this is somewhat the same setup i'm doing

Contains Two 10" Sub-Woofer (Lanzar SE10)
Impedance: 4 Ohms
Dual Jet-Port
High Quality MDF Construction
Quick Connect Speaker Terminal
SPL: 99db @ 1W/1M
Frequency Response: 39Hz - 1k Hz
Dimensions: 12.25"H x 27.5"W 11.25"D
700 Watts System

so its kinda like my setup, almost the same dimensions, mines a bit longer tho, same 4 ohms tho, dunno the frequency response so i dont know how its gonna sound (N) hopefully good.
so what do you guys think?? one or 2 ports on the magnet side or face side??

so what do you guys think?? one or 2 ports on the magnet side or face side??

it all depends on what you're going for. you should really take some time to read into port design since in a ported/bandpass box, its the port that determines the tuned frequency of the box

i agree with everyone...

people totally underestimate the importance of doing research on this sort of thing. even the smallest variation in volume, or where and how large ports are. thats even if you feel a bandpass enclosure is right for you. you should really learn what each of the specs of that speaker really mean, because all the information you need is right in front of you, and its all important.

its really hard to determine the outcome, unless someone has the same exact car/speaker/amp/headunit setup, which would be pretty rare. so i dont think theres any more advice that can be given besides what these guys have said.

take your spec sheet and do some homework. if you take a little time...you'll be very pleased with the results.

oh...a non ported bandpass would either leak/explode/or make no sound at all. the whole purpose of a speaker is to move air, which is how they make sound. no port would be like placing your hand on top of the sub, not allowing it to move.

good luck :thumbsup:

This may help you - http://www.diysubwoofers.org/bnd/4thorder.htm
learn how to build all types boxes correctly. Anyone can slap a box together, will is sound good?

Dont mean to jack the thread, but how much power can our stock alternators handle? I've been questioning the performance of stereos in 4g's because of their age, and the actual power produced by the stock alternator.

well for an idea, im running two 12" Alpine Type R DVC subs 1000w each, with an 800w amp, plus my speakers are on a 300w amp, with no problems.

The size of the box and of the port are determined by certain parameters that describe the speaker. Should be some kooky sounding stuff - QTS, Vas, Fs, etc. Either you can feed this stuff into a program or spreadsheet and calculate what size to make everything, or do like someone suggested and look to the speaker manufacturer for some suggested box sizes.

There's a little bit of tolerance in this, but there's a chance that you'll just happen to pick sizes that totally dont match your particular speaker and it could sound like ass. A little research in this dept will go a long way in how it ends up sounding.

That website jackassi posted is pretty good.

well this kinda sucks now
i've made my box already (been working on it for over a couple weeks now) just gotta put plexi glass on and wire it all up and thats all, i really hope i got lucky and it sounds good, if it doesnt i'm just gonna buy a premade system

i dont know why you would want a bandpass box?!?! they are bigger, tuned to a CERTAIN frequency and are the MOST DIFFICULT box design to make on your own...

what you should have made is a sealed box... they are nice and easy, and usually sound aight in all bass frequencies... ported is the next step...

should have consulted some stereo guys before you went into construction

Travis

i dont know why you would want a bandpass box?!?! they are bigger, tuned to a CERTAIN frequency and are the MOST DIFFICULT box design to make on your own...

what you should have made is a sealed box... they are nice and easy, and usually sound aight in all bass frequencies... ported is the next step...

should have consulted some stereo guys before you went into construction

Travis

I totally agree. I made my bandpass because i listen to a specific kind of music that normally has lots of sine wave in the 40-60Hz range and kickdrum in about the 55-65hz range.

A sealed box will be more suited to a wider range of music, but with a ported box you can make peaks in certain frequency ranges. with a bandpass, the box itself works as a crossover and only allows a certain frequency range to be reproduced.

well this kinda sucks now
i've made my box already (been working on it for over a couple weeks now) just gotta put plexi glass on and wire it all up and thats all, i really hope i got lucky and it sounds good, if it doesnt i'm just gonna buy a premade system

the only way you can know if a premade system is going to sound right is if it's designed for a particular speaker... there are a set of specs that you have to go by on a speaker that allow you to perform calculations for tuning.. that way you can figure out where and how many dB's of boost or attenuation you are adding to the frequency response ...

sealed boxes are easy to build :) there isn't really any tuning besides the total volume... and they have very tight bass / high power handling ...

"regular" ported enclosures and bandpass (recursive enclosure i.e. ported inside ported) allow you to tune the enclosure such that there are +/-dB boost/attenuation at certain points, determined by the enclosure size, port size, port length, etc... they will generally play louder given the same amount of power... but the tuning can be rather complicated, especially on a bandpass...

the default choice for sound quality .. sealed
the default choice for maximum dB SPL ... ported or bandpass


These are the best pre-fab boxes you can buy, hands-down and without a doubt...

http://www.subzeromfg.com

Don't get too discouraged, however... as you have put a lot of work into it.... Who knows... your box might sound good :)

it will definately be better than having NO subs :)

you know what, if you post the size box you made and the speaker parameters if you can find them i'll try to run it through a speaker program after xmas. it's not real hard to do and it'll show you what it should sound like. it'll also show whether some small changes might help it out.