NEEDAZ

Devestator, It sound like that was a band pass box, and probably a vary poor one. So you may have just gone from bad to bad. The key is a properly designed/properly built box. You can make a box that sound worse then a plate.
Red89, try to start a new post.

Jim85IROC

iTrader: (2)

I'll give quickie answers here, but I like Needaz's idea about starting a new thread. Let your question get the attention it deserves by having its own place. We can get more into depth there, but here are your quickies:

1. Yes
2. Yes.
3. If the internal volume changes, yes.

There are other easier, more effective ways to hide a stereo.

sully91rs

And after reading that novel, I agree.
Now I just have to kick myself in the a$$ enough to go build the d@mn box!

ScrapMaker

Yeah plates suck... but what really sucks is that someone actually suggest to build something out of the "cheapest plywood you can find."

I had to go take a shower after that one...

I wouldn't use anything thinner or less dense than 3/4" MDF...

HDF is great but is unecessary... at least you can brag about it later... and I've never seen a box that is thicker than 3/4"... but I bet it would work great.

heh, my friend want's to make a box out of steel now... he doesn't care how much it weighs... sigh, it's gonna take me some time to convince him how dumb that will be...

Jim85IROC

iTrader: (2)

Believe it or not, particle board's resonance properties are nearly identical to MDF. Where particle board really becomes a failure in my eyes is in the joints... glue just does not adhere the particle board pieces as well because it's so porous. Plus, the stuff is just a royal bitch to work with... splinters, stripped screws, broken edges, it's just a pain.

ScrapMaker

I always thought they were prone to leaking, just through the wood itself, since it's not uniform, different chunks of wood basically glued together...

devestator_x

iTrader: (1)

Ok after a half hour searching... I found MTX has changed the style of their Sledghammer boxes to ported, but mine is sealed (and about 4-5 years old). I had a T4510X3-A but the subs came in a RT10X3A style box that had a plexi windows in the back to see the spiders and wiring. I know what bandpass looks like, I had one once.

I dont know, maybe because I have a tiny budget amp hooked up, Im not pushing them hard enough to leak around the sides. I know I am underpowering them drastically (220 peak amp to 1500 peak subs cant remember rms)

Spazz698

Ok Im curious now.

I was thinking about pulling the carpet out of my trunk area (I have my reasons) fiberglassing the rear, in particular the well, then adding a plate and fiberglassing over that as well making it one solid piece (so that plate becomes one with the car) and doubling this as an enclosure as well. Now if you kept up with me would this be feasible?

Gummie

Completely. What are describing is creating a sealed box by fiberglassing the well then fiberglassing the piece of wood on top down assuming I understood you correctly.

ScrapMaker

it would be a LOT of work... and then you still need the wood on top... why not just build the box out of wood completely?

Spazz698

That is exactly what I was getting at. As to make a permanant built in box. Why not make one out of wood? I already have one, it gets jammed in the well and stuck (thanks to the cargo clip things that hold the cover in place) it's huge, things slip inbetween it and get stuck under it, etc etc. My idea was to make it so the subs will sit flush to the plate and if/when needed all I have to do is cover them with a removable plate to protect them.

And doing the fiberglass actually isnt a lot of work, it's fairly time consuming tho. But I was planning on doing some minor body work on my car either way so it's probably gonna end up being a "taking a break before I use a hammer to fix it" kind of thing.

ScrapMaker

you have to make the fiberglass pretty thick, if I remember correctly...

and you want to make it permenant?

hrm, why not just use the wooden box, and put a custom cover over it?

make it out of fiberglass if you want... or plastic or whatever...

Spazz698

Like i said the box I already have, and it's too big for my taste. The fiberglass one I was thinking up would be a good 4-6" shorter since it'll take up the entire space of the well and not be a gap of about 3" or so below it.
Yes it would be fairly thick, but they do make fiberglass sheets which would make things much easier. Now this isnt something I'll be doing soon, I want to take care of the mechanical issues first before even going into cosmetic/sound. Why make it permanant? my car's is apparently an obvious target to get broken into 3x so far since i had it (~4mo now) it makes thing much more difficult if they actually manage to get in.

ScrapMaker

good luck on all that...

but realize, they'll just pull your subs out of the box... they don't want the enclosure itself.

devestator_x

iTrader: (1)

but realize, they'll just pull your subs out of the box... they don't want the enclosure itself.

I've got an easy solution to that... use 2 allen head screws, 2 spanner screws, 2 philips head screws and 2 torx screws to hold in your subs. That wya they can't possibly have all the right size bits with them to get them out. They'll probably just get pissed at you and put 50,000 holes in the cones of them instead.

ScrapMaker

yup, 100% they will stab up the speakers... they will probably knife your seats, break your windows, hatch, windshield, and slash your tires...

that's what I would do if I was a thief... I mean, that takes what, all of 30 seconds to do all that damage?

kyle folds

True

After my brothers stuff got stolen twice I Made sure noone would take it again.

Every seam of the box was bolted together with 1/4" angle iron. Box was bolted down with carrige bolts through the body (Toyo p/u extended cab) Speakers installed with steel rivits. Made a steel box for the head unit attached to the dash mounts.

The head unit was destroyed, but still there, speakers bent but still there, box damaged but still intact.

Insurance paid $1,400 for everything including the damage to the dash.
Th good news is that these guys wanted his stuff so bad that they stayed and tried long enough for the cops to get there. In Ga. anything over $500 is felony, that is what they got.

kyle folds

/

ScrapMaker

cops, no cops, makes no difference.

Now his insurance will go up, AND those guys will be out on the streets in a few weeks... maybe months... guaranteed.

My personal preference is to have a completely-stock appearance... but that's tough to do with an aftermarket cd deck.

kyle folds

That was 2 years ago, insurance did not go up.

They were 16 ang got a year of boot camp and 5years probation. Thier parents had to pay the insurance company back.

ScrapMaker

Wow, that's probably the only theft story that actually had a happy ending... good stuff there.

sully91rs

The system works??? I'm amazed.

BruceEmbry

Here is a example of home gone subwoofer.

Jim85IROC

iTrader: (2)

It looks like a truck box with a gray panel in front of it.

BruceEmbry

No! I designed it to fit into the well of my Firebird. I orginally built the box back in 1990 for less then $60. It too big to fit an truck.

ScrapMaker

looks interesting... too bad you ported it!

BruceEmbry

The Ports are designed/setup to extend the low bass output of the speaker where their output starts to fall off at the lower frequencies. The ports are also setup below the resourance frequancy of the speaker. The resonance frequancy for the 8 inch drivers are around 50 Hz. The ports are tuned at 20-35 Hz.

Going down the road, you can feel the bass in your back without having to turn the system up very loud.

ScrapMaker

oh, 8"s... that's why

my friend built a sealed 8" box for an older f150 and it sucked... so I designed a port for it @ 39hz... sounded tremendously better...

otherwise, I'm personally against ports, unless you are using them to EVEN out frequency response... (which most people don't use them for that)

BruceEmbry

The four 8 inch drivers has more combined surface area then two 12 inch drivers.

ScrapMaker

Yeah but I'm used to two 15" subs, that combined, have more surface than three 12" subwoofers.

BruceEmbry

Not by much! It only take about 5 8-inch speaker to have the same surface area a 2 15 inch speakers. So you have 1/5 more surface area. BIG DEAL. I DON'T CARE!

ScrapMaker

well you brought up the surface area...

I have 353.25 square inches

you have 200.96 square inches

unless my math sucks but that should be about right...

Gummie

Few things. Different 8" woofers have different conal area. It depends on surround design, etc. Keep in mind that cone area means cone area and not area covered by surround. This is one of the reasons why JL has that huge roll type surround on their w7s - more cone area. For the best fair comparison look up the Sd of both drivers in question and do the math from there. Using JL's w7 line as a reference, two 12's will have more surface area than four 8's. Look it up yourself if you want to.

Also, I can think of about 5 different 8's off the top of my head with a Fs (resonant frequency) below 40 Hz and some below 30 Hz.

http://mobile.jlaudio.com/products_s...p?series_id=19
http://edesignaudio.com/product.php?...=Specs&cur=USD
http://www.soundsplinter.com/rli_ser...eneration.html
area a few for pretty decent prices.

Fs has more to do with cone mass than anything else. While larger cones do weigh more and have a lower Fs most 8's still have a fairly respectable Fs.

ScrapMaker

yeah, after we ported my friends 8"... it sounded kinda decent... but I just don't think they can really handle small, sealed boxes so well... it was like the woofer couldn't even move...

BruceEmbry

It doesn't matter A************

NEEDAZ

Why you get'n bent, you where the first one bring up surface area. And tuned to 20-35Hz, sounds real tuned. Post up some measurements on you box, I'm curious...

BruceEmbry

I'm not getting bent. Actruely I posted the picture of the my box to show what one can do for almost no money. The orginal posted wanted to know about "inexpensive sub box"

Back in 1990 I spent $60 for all materials, speakers, and passive sub-woofer crossover. My first set of speakers only cost me $10( I was working at the R-Shack). I went back to school to work on my engineering degree so I didn't have a lot of spare bucks.

At that time the box was completely passive. The orginal configuration of the box did exactly what I wanted it too, It extended the bottom end(bass) of the sytem.

Two years ago I replace the speakers, install the amp, and added an active sub-woofer crossover to the system.

The problem with the kids on this board, that they are all struck on size thing. ITS NOT ABOUT SIZE, IT ABOUT RESULTS!!!

As for measurements, if you talking about the enclosure, I will post them when I have time. But I do not have any of the orginal drawings that I made. As for surface area, please read the thread again, someone was craping on 8 inch speaders and ports.

Gummie

You were the first to bring up surface area as NEEDAZ posted.

Not meant as an attack or anything, but you were the one who started it. Don’t worry about defending what you have (ie your system) to anyone. Also, many here think you have two options when building a box: ported for loud and crappy sound or sealed for quieter and amazing sound. Most don’t know ported boxes can sound good. Also note that quite a few people here are still running plates and are in the baby steps of car audio.

The main reason why we keep bothering you about area and what not is because we're a bit skeptical that you managed to pull off a 4 cubed box with MDF. Also, I'm in the process of laying out my next box. I would love to go ported but I didn't think that I had enogh available space to do so. If you can prove me wrong that would be a huge plus in my book.

You don’t give many of us enough credit for what we’re talking about. I’m a hobbyist (I know, doesn't mean much), Jim85IROC is simply crazy in knowledge, NEEDAZ repairs car audio stuff for a living, etc. We understand the calculations involved in designing a ported box and that’s why we keep asking.

ScrapMaker

I was just playing around with WinISD and it seems that with most woofers, it's tough to keep a solid response curve in a ported box... hence the reason most people use it to make extremely 'loud' bass.. a lot of people tune their boxes to like 45-50hz so that it's even louder, but not deep enough... I dislike that a lot...

I really love the way that home theatre subwoofers sound, and they are ported... so yeah, definitely ported subs can sound good, but I still am not convinced that ported is the way to go in a car, especially if you have massive amounts of power... for most of us, I think we have enough power to drive even some of the largest woofers in some of the smallest enclosures...

in your case, it was obviously a good idea to port your enclosure

Gummie

I'm not sure what you're doing in WinISD but here you go... (see attached).

When you first load the woofer and select a box type WinISD will calculate the 'ideal' box for you.

I will agree that a lot of prefab boxes (ie the ones you buy at cc/bb) are tuned way too high but most people who are into serious car audio will tune their box for a flat responce.

Gummie

Here's a more extrme example..

ScrapMaker

wow that's almost the flattest response I've ever seen!

must have been the characteristics of the woofer but how big are these boxes? to get a response like that I'd assume you'd need about 3 cubic feet for a single 15"

Gummie

The first graph is of a 12" and the second is of an 8". Check out the pictures for more info. Each window shows box size, tuning frequency (if applicable), woofer mode, etc. I chose the first woofer randomly but I remembered the difference with the kicker so I grabbed that for the more dramatic graph.

ScrapMaker

yeah the ported box is twice the size though... seems unfair to the sealed version

jjs_world

To go back to previous words spoke by several different peeps in this thread.
Some prefer a Sealed box, some vented or ported boxes, and some want the plate. Everyone has thier opinion on sound.
The sealed box offers a more tighter hit on the bass and does NOT drop or give you that very low freq. of some bass. To where the vented or ported box does drop to the lower bass sound, and actually uses more of the flex in the sub woofer.
The plate is good for a free air subwoofer, but if you use a sealed sub for the same app. it will sound like a reagular speaker. The subs are actually rated and an advisory is issued with every sub made for the recommendations on obtaining the optimum performance from your speaker.
You may take a Kicker Comp VR 12, put it in a sealed box, and think it sounds great and then put it in a vented box, and it may burst the back window out, then switch to a plate, and get the same sound as the vented box, but not the same power behind the push. In the end result the bass line doesn't travel as far, and not as hard of a hit. I almost forgot, you also need to make sure you have the recommended airspace for the speaker, with the correct size vents in the box for the MAX output of your sub.
But it is also what sound you prefer, and what you want!

9177

My .02

Jim and the others are 100% correct on the idea of plates. There is no way short of glassing the well (which makes a box) that you can separate the sound waves from the front of the sub and the back. This is all you are trying to do when building a box or mounting IB. In a ported box you are creating a lag in the time the sound travels from the rear side of the sub to the front via you port figured by the port tuning. This makes a ported box utilize both the front and rear sides of the cone to make sound and why a ported sub sounds twice as loud (theoretically). In my experience a ported sub has a certain bandwidth that is actually sounds good at. I tune pretty low so they tend to sound "muddy" ~ 60-80 htz. I’m sure there is a theory on how to figure this but I don’t know it off hand. Anything below tuning should be considered sound that can't be produced. The idea that you can not get good SQ from a ported box usually comes from people who have only heard prefab ported boxes which are tuned very high and have no regard to what the sub wants.. A sub can only sound as good as the box made specifically for it. Not all subs do well ported, and not all subs do well sealed.

There are pros and cons between all of these box design/sub mounting idea, all of which Jim spent a whole lot of time typing a page that explains pretty much anything that can be told.

aaron7

iTrader: (7)

Wow, lots of technical posts... I ain't reading all that...

Plates do suck. I had one MADE by MTX with two 12" subs for the 3rd gens, and it sounded like ***.

Also, I put free air Pioneer subs (12's) into a box that had about 1cf for each, and they sounded pretty decent! Hey, it was my first system... I had it before I bought a car!

jamon8

iTrader: (3)

I went with a plate. but I fiberglassed it in.
1- I used rubberized undercoating inside the well and the bottom of my plate.
2- I made the plate extend to the end of the frame humps.
3- I made a brace in the middle with a 2x4 on the plate, a 2x4 on the bottom of the well(shaved to meet the contour), and two 2x4 braces holding them together.
4- I also used metal angle braces to hold it together better.
5- all that was undercoated using a gallon can of undercoating and some rubber gloves. I also sealed the inside of the box with undercoating and a flashlight.
6- On the bottom 2x4 in the well I used two bolts to secure it to the well.
7- on the top where the I put the plate on the frame rail humps, i used heavy duty liquid nails and them bolted it down at each corner.
8- I bought some fiberglass resin Jelly and spread it all around the outside of the PLATE!
9- I covered the PLATE with black velvet.
10- cut the interior pieces to fit.

I know that you guys think that this is a fiberglass box but it is a PLATE! I have heard Why dont you just make a box to fit.

I want all the space I can get because I built this car for road trips and I need every bit of space I can get.

All I have to say is PLATE PLATE PLATE, PLATE PLATE and oh yeah PLATE!!!!!

money spent on PLATE $50 proving plate haters wrong PRICELESS

It sound bad @ss

CAN DO -SEABEES

jamon8

iTrader: (3)

Just so we get the name right it is the double sealed plate.

ScrapMaker

wow jamon8... why on earth go to so much work to do a plate setup, when you could have easily done a sealed box instead?

it looks like you actually went to more work than to make a sealed box...