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95Prober
05-28-2005, 11:09 PM
hi guys. now i know that it takes a bit of calculation for a ported design, with port, tuning etc. but now say if you want a sealed box. would you only get ONLY the ONE result even if you had many different people trying to do it?? i mean, its basically easier i assume, and since there is no tuning and port, wouldnt the inside dimensions be ALWAYS the same if say 5 guys tried to design a SEALED box with the same subs??

also, is there any particular equation to find out your TOTAL inside dimensions for a sealed? of course i have my T/S numbers. thx!!

djjdnap
05-28-2005, 11:14 PM
??
I'm a lil confused, but depending on how much area you use the boxes will sound diff.
Also the material you make the box out of.
And also how well you seal it.
Also things inside the box will make diffrences as well, by displacing more area, such as braces and what not.
You can also use polyfill and other things to make your sealed box sound diff.

95Prober
05-29-2005, 02:30 AM
well, im going with mdf 3/4". also, this is this first box, so i wont put poly-fill untill i try without it.
i guess basically, if you went with a rectangular shape and not hard to build (the cuts), how do determine the inside volume?? from T/S numbers ??

squeak9798
05-29-2005, 04:20 AM
but now say if you want a sealed box. would you only get ONLY the ONE result even if you had many different people trying to do it?? i mean, its basically easier i assume, and since there is no tuning and port, wouldnt the inside dimensions be ALWAYS the same if say 5 guys tried to design a SEALED box with the same subs??

No no no no no.


Different sized sealed boxes will give you different alignments, which is called the Qtc. Along with the differing Qtc's, you'll get different F3's (point at which the low end response rolls off to -3db down), different Fc (resonant frequency of the "system" [sub in the box]), different frequency responses, different transient responses, different group delay.....anything that can be different will be different.

The bigger the box, the lower the Qtc. The smaller the box, the higher the Qtc. Qtc of .5 is considered to result in perfect transient response. Qtc of .577 will have maximally flat group delay. Qtc of .707 (what most people consider to be the "ideal" Qtc - it has the best set of trade-offs) will have the flattest frequency response and lowest F3, with a transient response and group delay that "isn't too bad". And as you go higher in the Qtc range (.8, .9, 1.0, etc) you start getting a larger and larger peak in the frequency response in the upper bass/lower midbass region (which most people will claim makes the sub sound "tight" or "punchy"), worse and worse transient response/group delay, and worse and worse low frequency extension.

So, what you want to do is figure out what Qtc value you want to go for. If you want to go for a Qtc of .707, then you will need to find the appropriate box size. If you want a Qtc of 1.0, you again need to determine the appropriate box size.

Now, keep in mind that as box size increases, mechanical power handling decreases (efficiency increases), and as box size decreases, mechanical power handling increases (less efficiency). Also, the smaller box sizes will have more output than the larger box sizes.


Now that I'm sure I have you sufficiently confused (I **** at explaining things), here are some good links on the subject:

http://www.diysubwoofers.org/sld/ (be sure to click the corresponding links to the left)

http://www.carstereo.com/help/Articles.cfm?id=29 (nice graph and good general info)





also, is there any particular equation to find out your TOTAL inside dimensions for a sealed? of course i have my T/S numbers. thx!!

And you would use the T/S parameters to determine what box size is needed for which Qtc value, aswell as what the actual F3 points and such would be.

djjdnap
05-29-2005, 04:49 AM
isn't .707 what you multiply Voltage by to get rms?

weird its the ideal qtc also

flakko
05-29-2005, 04:51 AM
wow... thats a mouthful squeak...

95Prober
05-29-2005, 12:33 PM
Vb = Vas/((Qtc/Qts)^2-1)


well this is what i got assuming with Jmac's formula, and as squeak said, if i want what the typical ideal route is and go with .707 Qtc......

Vb = 1.94cu.ft / ((.707/ .31)^2-1 = 3.801

is this right ?? i think its wrong!

also, what does Vb stand for? box volume?

my total would be...?? PLUS 0.089 for sub displacement correct?? so....my grand


total would be ??

*NOTE- my Fs = 25 on my subwoofer spec sheet

squeak9798
05-29-2005, 06:33 PM
:word:

One thing Jmac forgot to mention was the Vas needs to be in liters for the formula, not cubic feet. So;

Vb = 54.934L/((.707/.31)^2-1) = 13.075L

Then you convert that to cubic feet; which is 0.462cuft (as Jmac said)

And yes, Vb is box volume.

95Prober
05-29-2005, 07:40 PM
:word:

One thing Jmac forgot to mention was the Vas needs to be in liters for the formula, not cubic feet. So;

Vb = 54.934L/((.707/.31)^2-1) = 13.075L

Then you convert that to cubic feet; which is 0.462cuft (as Jmac said)

And yes, Vb is box volume.


PLUS .0089 for sub displacement ?? if so = 0.551 cu.ft PER SUB.

also, if i use MORE than one sub, then just multiply by the amount of subs ???

squeak9798
05-29-2005, 09:42 PM
PLUS .0089 for sub displacement ?? if so = 0.551 cu.ft PER SUB.

also, if i use MORE than one sub, then just multiply by the amount of subs ???


Yes and yes

squeak9798
05-29-2005, 09:43 PM
It works with either one ...
If you use Vas in liters, you'll get Vb in liters ...
If you use Vas in cubic feet, you'll get Vb in cubic feet ...

Vb = 1.94/((Sqrt(0.5)/0.31)^2-1)
Vb = 0.4615845506 ft^3

Vb = 54.93468239/((Sqrt(0.5)/0.31)^2-1)
Vb = 13.07061891 liters

0.4615845506*1728*2.54^3/1000 = 13.07061891


What can I say, I'm a 'tard. Brain farts ****.

95Prober
05-29-2005, 09:46 PM
seems so small of a box for a single sub. even considering they are the pioneer premier line. so , a small box like this compared to a lager box would give me what type of sound? i mean a small sealed or a med./large sealed. is there a HUGE difference in sound?? i know ported makes i big difference.

squeak9798
05-29-2005, 09:56 PM
is there a HUGE difference in sound??

Can be, yes. If you start going larger, you'll start lowering the Qtc of the enclosure. This will give you less overall output, and a sound that some people would probably consider "dry" or "lifeless". Plus the enclosure would start it's low frequency roll-off higher in the frequency band. Transient response and group delay would technically increase though.

95Prober
05-29-2005, 10:01 PM
Can be, yes. If you start going larger, you'll start lowering the Qtc of the enclosure. This will give you less overall output, and a sound that some people would probably consider "dry" or "lifeless". Plus the enclosure would start it's low frequency roll-off higher in the frequency band. Transient response and group delay would technically increase though.


haha! so im simple newb terms and in ur opinion, i should stick with the Qtc. or .707 ??

95Prober
05-30-2005, 10:16 AM
i mean, is the overall consensus, usually stiick with the .707??

squeak9798
05-30-2005, 12:52 PM
Yes

95Prober
05-31-2005, 12:55 AM
Yes


but squeak9798, i calculated the same subs that my brother has from the pioneer premier line, EXCEPT his are SVC subs and mine are DVC. now his specs are a little smaller and using the equation that you and Jmac posted, i got a

total of 0.3549 plus sub displacement of 0.0089 = GRAND TOTAL - 0.3549 cu ft.

my total is a little larger at 0.462+0.0089= 0.551.

but my brother numbers seem SO small. have you ever heard of people making a single sub box that small? at the moment he got them in a pre-fab at aroung .8 cu.ft maybe or more per sub. he's running 2. but i told him to go with building a box and that we could use these numbers. i guess if 0.3549 is what it sayd then i cant argue. its just i never seen a box that small. i guess its coz most people here run pre-fab junk. but even reading of the forums, i never came across it. should it sound good in that small a sealed box ?? thx!

95Prober
05-31-2005, 11:26 AM
part 2 of my questions:

is it even POSSIBLE to make a small sealed box for 0.3549 ?? if so, what kind of dimensions of the interior (WIDTH / DEPTH / HEIGHT) would he need??

squeak9798
05-31-2005, 11:28 AM
but squeak9798, i calculated the same subs that my brother has from the pioneer premier line, EXCEPT his are SVC subs and mine are DVC. now his specs are a little smaller and using the equation that you and Jmac posted, i got a

total of 0.3549 plus sub displacement of 0.0089 = GRAND TOTAL - 0.3549 cu ft.

my total is a little larger at 0.462+0.0089= 0.551.

but my brother numbers seem SO small. have you ever heard of people making a single sub box that small? at the moment he got them in a pre-fab at aroung .8 cu.ft maybe or more per sub. he's running 2. but i told him to go with building a box and that we could use these numbers. i guess if 0.3549 is what it sayd then i cant argue. its just i never seen a box that small. i guess its coz most people here run pre-fab junk. but even reading of the forums, i never came across it. should it sound good in that small a sealed box ?? thx!

Well, unless the T/S parameters are incorrect....yes.

squeak9798
05-31-2005, 11:30 AM
part 2 of my questions:

is it even POSSIBLE to make a small sealed box for 0.3549 ?? if so, what kind of dimensions of the interior (WIDTH / DEPTH / HEIGHT) would he need??

Um, yeah.

12" x 8.75" x 6" = .36cuft

tRiGgEr
05-31-2005, 11:43 AM
Um, yeah.

12" x 8.75" x 6" = .36cuft

Hope you have a 6.5" driver. That box wont even fit a 8" sub.

tRiGgEr
05-31-2005, 11:45 AM
Oh and 95Prober,

.5 cubic feet is a pretty small box. Trust me. My ported box for one speaker nets around 3.15 cubic feet. Thats a big box:D

95Prober
05-31-2005, 11:50 AM
Well, unless the T/S parameters are incorrect....yes.


so it should sound great with that size a small then. i hope so. and no the T/S numbers are correct. i checked many times. i know pioneers arent the greatest and largest in dimension subs but i thought it would have to be bigger. ah well, i better learn to follow the numbers and stop comparing my subs to other subs and boxes

95Prober
05-31-2005, 11:53 AM
Oh and 95Prober,

.5 cubic feet is a pretty small box. Trust me. My ported box for one speaker nets around 3.15 cubic feet. Thats a big box:D

well, you cant compare my subs for a ported box, can you? both are totally different. if i port mine, it should and would be bigger coz of the different modifications you can make towards port and tuning. BUT this is for a sealed. wouldnt squeak's numbers work? look fine to me >12" x 8.75" x 6" = .36cuft

squeak9798
05-31-2005, 11:58 AM
Hope you have a 6.5" driver. That box wont even fit a 8" sub.


Hey, I was just showing it was possible :p:

tRiGgEr
05-31-2005, 12:00 PM
well, you cant compare my subs for a ported box, can you? both are totally different. if i port mine, it should and would be bigger coz of the different modifications you can make towards port and tuning. BUT this is for a sealed.

I was not comparing :read: I was just pointing out that .5 cubic feet is small. And by stating my 3.15ft^3 box in size comparison, you could see that .5ft^3 is very small.



wouldnt squeak's numbers work? look fine to me >12" x 8.75" x 6" = .36cuft.

How do you plan on putting a speaker in a box that is 12x8.5"???

A 12" speaker requires 13.5x13.5, a 10" requires 11.5x11.5, an 8" requires 9.5x9.5 at the minimum.

I think he was just showing you how to make a .36ft^3 box.

95Prober
05-31-2005, 12:00 PM
also, after just checking with pioneer on their site, they recommned a 0.6 cu.ft. its only NOW i seen it.

BUT, that is only a good recommneded size for the average person to them a rough idea. since i am going with the EXACT specs, would it hurt the sub any going UNDER the 0.6 and making it 0.36 ??

tRiGgEr
05-31-2005, 12:06 PM
also, after just checking with pioneer on their site, they recommned a 0.6 cu.ft. its only NOW i seen it.

BUT, that is only a good recommneded size for the average person to them a rough idea. since i am going with the EXACT specs, would it hurt the sub any going UNDER the 0.6 and making it 0.36 ??

Nope.

95Prober
05-31-2005, 12:07 PM
I was not comparing :read: I was just pointing out that .5 cubic feet is small. And by stating my 3.15ft^3 box in size comparison, you could see that .5ft^3 is very small.




How do you plan on putting a speaker in a box that is 12x8.5"???

A 12" speaker requires 13.5x13.5, a 10" requires 11.5x11.5, an 8" requires 9.5x9.5 at the minimum.

I think he was just showing you how to make a .36ft^3 box.


ahh. yeah i understand. but im so confused. i mean, i go out and use the EXACT numbers and i get a result that cant even fit in the size that i get (0.365 cu.ft.)

so, i cant fit it right, i guess i have to go higher to the LEAST / SMALLEST possible
BOX which would be : 11.5 x 11.5 x depth, which i assume 6 inches at least

?????

tRiGgEr
05-31-2005, 12:10 PM
ahh. yeah i understand. but im so confused. i mean, i go out and use the EXACT numbers and i get a result that cant even fit in the size that i get (0.365 cu.ft.)

so, i cant fit it right, i guess i have to go higher to the LEAST / SMALLEST possible
BOX which would be : 11.5 x 11.5 x depth, which i assume 6 inches at least

?????

What is the mounting depth of your speaker???

If it is less than 6" your good. 11.5 x 11.5 x 7.5 with building material of .75" would equal .35ft^3 before speaker displacment.

95Prober
05-31-2005, 12:25 PM
What is the mounting depth of your speaker???

If it is less than 6" your good. 11.5 x 11.5 x 7.5 with building material of .75" would equal .35ft^3 before speaker displacment.

i got it! but lets say for example you get a result using the TOTAL number including your sub displacement, like i did, which with displacement is 0.3638 cu.ft

now is that total number, the dimensions the box is supposed to be on th outside, or is that an interior cu.ft size and you have to figure in wood later????????

tRiGgEr
05-31-2005, 12:31 PM
i got it! but lets say for example you get a result using the TOTAL number including your sub displacement, like i did, which with displacement is 0.3638 cu.ft

now is that total number, the dimensions the box is supposed to be on th outside, or is that an interior cu.ft size and you have to figure in wood later????????

Wow that made no sence at all :crazy:

Multiply your box's internal dimmensions. L x W x H = Box volume. Divide that by 1728 to get cubic feet. Subtract the speaker displacment. You should have a .36ft^3 box.

So lets say your speaker displaces .069 cubic feet. A box of 12.5 x 11.5 x 8.25 would work.

So internal of 11 x 10 x 6.75 = 0.43. subtract 0.069 = .36ft^3

Decipha
05-31-2005, 12:50 PM
hey prober its me decipha i thought you had 4 10's ?

95Prober
05-31-2005, 01:48 PM
hey prober its me decipha i thought you had 4 10's ?


hey man whats up? yeah, the 4 10's are mine. but my brother got 2 of the same series except SVC premiers, so im trying to help him. i pmed you. let me know what you think ,?? see ya!

da_tank
05-31-2005, 01:56 PM
won't he need a pretty powerful amp to make up for "loss" of volume due to box being smaller than a ported box would? 'cause it should take more power to run the sub now.????

95Prober
05-31-2005, 02:02 PM
won't he need a pretty powerful amp to make up for "loss" of volume due to box being smaller than a ported box would? 'cause it should take more power to run the sub now.????

yeah, never thought of that. great point. anyone ?? i think my bro wants to try the sealed AND make ported to compare. its just that when we make the sealed, we want to make it the best soundind and getting the most deep bass out of it as we can. then try ported.

95Prober
06-01-2005, 12:59 AM
Pioneer usually recommends enclosures a little on the large side for better sound quality ...

If this is a 10" sub, you could go with 11.5" x 11.5" x 7.75" (external, assuming you're looking for 0.36 ft^3 gross) ...


well no Jmac , it isnt for gross, i must achieve 0.346 cu.ft after displacement. so i think ill need 0.4395 cu.ft TOTAL inside dimensions MINUS the 0.089 displacement will give me the remainder of 0.3505 cu. ft. i think its right?

these are weird dimensions INSIDE DIMENSIONS - (H 11.25 X W 10 X D 6.75), but its the CLOSEST and EXACT i can get to the 0.346 cu.ft that the T/S numbers call for. i know i dont have to be exact, but i want to just for fun and see what the sub will put out and how it will perform. of course, i know i can go a little larger. but i DONT want to until i try this way out first. these numbers are almost exact ASSUMING i go with a Qtc. of .707 i'm even going UNDER pioneers recomendation. but this is what the T/S numbers tell me with a Qtc of .707.

also , yes its for a 10" sub.

95Prober
06-01-2005, 10:40 AM
Misleading bastard :p:

Anyways, I'd go with 12" x 12" x 8.5" external (10.5" x 10.5" x 7" internal) = 0.3576 ft^3 ...

yeah, sorry, that was me :)

anyway, Jmac or anyone else, what do you think about another guys post, saying that since its going REALLY SMALL , even under the pioneer recommendations, that i will need MUCH MORE power coz of the conditions the sub is in???

i read about that somewhere, but i can find where. like the smaller the box the less efficient or more amp power is needed???? something like that, but dont quote me.

tRiGgEr
06-01-2005, 11:16 AM
yeah, sorry, that was me :)

anyway, Jmac or anyone else, what do you think about another guys post, saying that since its going REALLY SMALL , even under the pioneer recommendations, that i will need MUCH MORE power coz of the conditions the sub is in???

i read about that somewhere, but i can find where. like the smaller the box the less efficient or more amp power is needed???? something like that, but dont quote me.

Yes the speaker will want more power being in a small sealed box. Not because your going under pioneers recommendations, just because that is the nature of small sealed box's.

You don't "have" to give it more power. It will just be able to handle more power.

95Prober
06-01-2005, 11:32 AM
Yes the speaker will want more power being in a small sealed box. Not because your going under pioneers recommendations, just because that is the nature of small sealed box's.

You don't "have" to give it more power. It will just be able to handle more power.


so it will be able to handle MORE power than say, if it was in a larger box?

also, is that the advantage of running a VERY small box, or is there an advantage of any type? i guess its not an advantage the sub wants more power.

also, what can i expect the bass to be like ??

squeak9798
06-01-2005, 11:41 AM
so it will be able to handle MORE power than say, if it was in a larger box?

Mechanically, yes


also, is that the advantage of running a VERY small box, or is there an advantage of any type? i guess its not an advantage the sub wants more power.

Well, I don't know if I would call lower efficiency an "advantage". Just a side affect.


also, what can i expect the bass to be like ??

Um...like bass :confused: Your car, power, installation and settings are going to determine that. Using a box with a Qtc of .707 the sub in the box will have a flat frequency response, low F3 and decent transient response and group delay. But, how it actually sounds will be install dependent. You can stick the same box with the same sub in two different cars, and it can sound totally different.

95Prober
06-01-2005, 11:50 AM
"flat frequency response, low F3 and decent transient response and group delay. "

sorry from a newb, but in easier words what does this mean?

DFW40
06-01-2005, 12:15 PM
http://www.bcae1.com/

live learn know this page it is the bible

95Prober
06-01-2005, 12:38 PM
http://www.bcae1.com/

live learn know this page it is the bible


well, i know that site. just i want to know in guys on these forums terms.

squeak9798
06-01-2005, 12:56 PM
"flat frequency response, low F3 and decent transient response and group delay. "

sorry from a newb, but in easier words what does this mean?

Good sound quality and good low frequency extension.

But, like I said; that's simply the box's affect on the subwoofer. How it actually sounds will be vehicle/setup dependent.

95Prober
06-01-2005, 01:15 PM
Good sound quality and good low frequency extension.

But, like I said; that's simply the box's affect on the subwoofer. How it actually sounds will be vehicle/setup dependent.

well, with low frequency extension, does that mean i will get low, deep , hard hitting bass, or that punchy bass i f you know what i mean?

as far as car set-ups, i hear ya. well the subs are goin a hatchback, big 3 is done, 0/1 guage for amps in trunk, stock alt., maybe an Optima and the amps are going to be mine to try out. JL 500.1 in his car. we want to put 2 of these SVC subs wired at 2 ohms, and run a sealed box with those specs you and some others nicely helped out on. although i was calculating the inside dimensions for 1 box, we will double the box for 2.

squeak9798
06-01-2005, 04:03 PM
Low frequency extension is how low the sub will play.

DFW40
06-01-2005, 04:47 PM
Just go with the higher end of what the manufac recommends. I have always had the best results with this. If they recommend 1.5-2.25 I'd go with the 2.0 and so on.

95Prober
06-02-2005, 01:10 AM
Low frequency extension is how low the sub will play.

so LOW bass notes? hittin deep?

95Prober
06-02-2005, 11:04 AM
im confused, coz if "low frequency extension" gives that LOW ,deep bass, which im not sure, isnt it the BIGGER the box the more boomier and lower you get? how can a small sealed box, 0.365 cu,ft sound deep???

squeak9798
06-02-2005, 11:43 AM
Because that's the appropriate sized box for that sub (given the specs you listed). What is considered "large" or "small" for one sub, won't be for another.