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thai_creeper
03-25-2006, 08:07 PM
umm i just got done making my first box, sorry no pics cuz my dig cameras broken but..i ****ed up on one of the measurements, so the only thing wrong is that the port is off about 3/4 of an inch towards the inside. i used this one of moe's plans http://img23.imageshack.us/my.php?image=295cubes34hz3625sqin2dd.png so i don't know if u guys will know wat im talkin about but the L portion (the two port pieces) are to the right 3/4 of an inch from where they should be (lookin at the top view) soo im sure this will significantly offset the box with volume and port size and all that, any way to predict how much off or in terms of wat will the sound be like? i just finished it today so im lettin the silicone set for a day before i put my sub in. would it be so bad that i should knock out that port section and put it in right(would this be hard, removing and redoing part of the box) or maybe redo the whole box? any advice/thoughts appreciated.

Ingleside
03-25-2006, 08:37 PM
looks like you increasd your port area on one part of the port and not the other.
typically when you increase port area you will raise the tuning frequency.
to be honest i dont really know how much this will change things because one end of the port has the right area but the other does not.
how did you mess up? did you cut the front baffle too short?

thai_creeper
03-26-2006, 12:00 AM
thanks for the input mayn, all the cuts were right, i just forgot the port should start behind the front face, instead i thought it would go to the left of the front face(lookin at the box straight on. i dont know if you get wat im sayin but yea, i guess i might as well try it out and see how my sub sounds. i just bought my first sub and everything last november so maybe i wont be able to tell if it sounds a lil bad anyways, im just hoping it sounds a lot louder and stays hittin low notes compared to my small sealed box (12" L5)

springy101
03-26-2006, 12:04 AM
so instead of the port being 2.5" wide its now 1.75" wide?

thai_creeper
03-26-2006, 12:22 AM
umm its too much to the right so instead of 2.5" wide it's 3.25" wide from the left side but it's still 2.5" from the short port piece to the back wall. hope that clears things up let me know if you need more explaining

Trixter
03-26-2006, 11:21 AM
the thing that i am worried about is that the port has a different area at each end. what i would do is cut another piece, 14.5H x 11.75L, and put it on the inside of the inner port wall, like the pic shows in blue. i doubt that the .06cu' of the piece that you meesed up will affect the box volume that much.

-cut a couple pieces of wood, 2.5" wide x 11.75" - 12" or so long.
-cut your 14.5 x 11.75 piece.
-apply wood glue to the side on the 11.75 x 14.5 piece and brush it evenly.
-slide it into the port opening and make it flush with the front.
-use the 2.5 x 12 pieces to wedge into the port and hold the new piece until it dries.

http://img204.imageshack.us/img204/4025/295cubes34hz3625sqin2dd8ab.th.png (http://img204.imageshack.us/my.php?image=295cubes34hz3625sqin2dd8ab.png)

~Magick_Man~
03-26-2006, 11:46 AM
the thing that i am worried about is that the port has a different area at each end. what i would do is cut another piece, 14.5H x 11.75L, and put it on the inside of the inner port wall, like the pic shows in blue. i doubt that the .06cu' of the piece that you meesed up will affect the box volume that much.

-cut a couple pieces of wood, 2.5" wide x 11.75" - 12" or so long.
-cut your 14.5 x 11.75 piece.
-apply wood glue to the side on the 11.75 x 14.5 piece and brush it evenly.
-slide it into the port opening and make it flush with the front.
-use the 2.5 x 12 pieces to wedge into the port and hold the new piece until it dries.

http://img204.imageshack.us/img204/4025/295cubes34hz3625sqin2dd8ab.th.png (http://img204.imageshack.us/my.php?image=295cubes34hz3625sqin2dd8ab.png)

x2

that should work well enough.

~Magick_Man~

thai_creeper
03-26-2006, 01:26 PM
thanks a lot for the ideas, that makes a lot of sense. the port(both pieces together) is off to the right by 3/4" so the front/face piece overhangs it by 3/4" so should I just cut a piece equal to the longer port piece plus 3/4" for the smaller port piece? sorry i can already tell that is very confusing, in reference to your picture, i was thinking cut the blue piece but only up to the front piece. haha if that doesnt make sense either im pretty sure i get your idea. im confused about what the 2.5 x 12" pieces are for though, i know you said wedging but im not sure how and where..i was thinking just stick the extra port piece against the port with glue like you said and i thought i'd screw them together reaching in the sub hole.

Trixter
03-26-2006, 02:53 PM
the 2.5 x 12 pieces are to put inside the port temporarly to push your new piece in place, one on top and the other on the bottom...since your port is 2.5" wide. screwing from inside would work as well. whatever you can do to get it tight and keep it 2.5" wide....

thai_creeper
03-26-2006, 03:05 PM
oh alright, i think screwing it would be easier for me. i think ill do that next weekend since i don't have access to anything for the rest of this week. i was eager to see how the box sounds though so i just put it in, i see a significant difference in bass for most songs, some songs seem the same as before though but im not mad, i feel like the 6 hours of work paid off since i didnt have to spend much doing it myself. other things i noticed is that before you couldnt really tell i had a sub standing outside my car but now u can hear it a lot more from the trunk standing outside, and also my rear view mirror moves up an inch every time the sub hits haha. still gonna add that extra piece though, hopefully it makes it sound even better.

thai_creeper
03-27-2006, 11:43 PM
also wanted to get input on this:

pepsifiend69 said:
"double baffle the front for another 3/4 of an inch, and then mount the sub on another round baffle around the rim of the sub for another 3/4"...that should give you enough room, might look a little akward, but it'd probobly work, just make sure you seal it up good."

for someone to get their sub far enough from the port wall, should i do this to make up for the lost volume by the extra thick port wall? or would that not be worth the trouble? thanks for any input.

spitfirees20
03-27-2006, 11:55 PM
also wanted to get input on this:

pepsifiend69 said:
"double baffle the front for another 3/4 of an inch, and then mount the sub on another round baffle around the rim of the sub for another 3/4"...that should give you enough room, might look a little akward, but it'd probobly work, just make sure you seal it up good."

for someone to get their sub far enough from the port wall, should i do this to make up for the lost volume by the extra thick port wall? or would that not be worth the trouble? thanks for any input.

I had to shell out and buy some MDF rings, it seems the easiest, but I guess that way would work too.

thai_creeper
03-27-2006, 11:58 PM
oh how much are mdf rings? do they make them square shaped for kickers too?

Trixter
03-28-2006, 01:32 PM
if your doing it because of the .06cu' extra because of the port, i wouldn't even bother. if you want it for support, which in most case that is what this would be used for, then go ahead. in your situation, i wouldn't bother, spl competing, then i would.

thai_creeper
03-28-2006, 06:50 PM
if your doing it because of the .06cu' extra because of the port, i wouldn't even bother. if you want it for support, which in most case that is what this would be used for, then go ahead. in your situation, i wouldn't bother, spl competing, then i would.
thanks for the advice trixter, umm could you verify how you calculated the .06 cu extra? i calculated (10.25+.75)(length) X 14.5(height) X .75(width) and divided by 12 and got 9.97 haha which i have no idea what to do with..if it is just a minimal amount of volume loss and you think its fine then ill just forget about it after making the port widths equal, i just wanted to make sure i got the best sq btw, after trying it out how the box is now im happy with the spl just wanted to make sure it hits the low notes

Trixter
03-28-2006, 07:55 PM
(10.25 X 14.5 X .75) / 1728 = 0.0645

i don't know where you got the 10.25 + .75 from??? and divided it by 12???

volume = (H X W X L) / 1728

hope this clears thing up...if not, lmk

thai_creeper
03-28-2006, 08:15 PM
(10.25 X 14.5 X .75) / 1728 = 0.0645

i don't know where you got the 10.25 + .75 from??? and divided it by 12???

volume = (H X W X L) / 1728

hope this clears thing up...if not, lmk
thanks for all the replies trixter, if u look at the plans http://img23.imageshack.us/my.php?image=295cubes34hz3625sqin2dd.png in the first picture, i have my port .75" to the right from where its supposed to be, so to make the port width right i'll have to cut out a piece that's of length: 10.25(the original length of the longer port) plus .75"(covering the width of the smaller port piece) to fully cover the side to the left of the (upside down L) port, see wat im sayin? if not ill try to explain differently..why is it divided by 1728? for some reason i thought if i multiplied the 3 things it would give me the volume in inches and id divide by 12 to get the volume in cubic feet

Trixter
03-28-2006, 11:10 PM
the piece that your adding will not be added as displacement inside the box. the port volume and the materials that it is made out of are subtracted from the box volume. the is the port's displacement. the volume of this piece does not matter and does not need to be figured or accounted for.

if you have 1cu' that 12" x 12" x 12". 12x12x12=1728.

when you measure you get the cu" and then divide by 1728 to get the cu'. your theory would work if you divided your numbers by 12 first and then multipled them.

whatever the length is from the front to the back is what it needs to be. to me it looks like 10.25 + .75 (for the rear port wall section) and another .75 (to make it flush with the front of the box.

thai_creeper
03-28-2006, 11:31 PM
the piece that your adding will not be added as displacement inside the box. the port volume and the materials that it is made out of are subtracted from the box volume. the is the port's displacement. the volume of this piece does not matter and does not need to be figured or accounted for.

if you have 1cu' that 12" x 12" x 12". 12x12x12=1728.

when you measure you get the cu" and then divide by 1728 to get the cu'. your theory would work if you divided your numbers by 12 first and then multipled them.

whatever the length is from the front to the back is what it needs to be. to me it looks like 10.25 + .75 (for the rear port wall section) and another .75 (to make it flush with the front of the box.
with that last paragraph i think you might have it confused, if i add a piece 10.25+.75 it will touch the front baffle, right now the front over hangs the port by .75". i didnt know that the port's volume isn't accounted for. if you do everything exactly by the plan though but you have one port wall "doubled" in a sense, wouldnt that extra wall need to be accounted for if it wasn't in the original plan? i dont know much about ported boxes, just thought to get the best sound you'd have to get your box as exact to the plan as you can.

well for the most part, if ur opinion still is that it's not worth the trouble adding an extra square baffle to even out the volume difference then i'll take your word for it, if it would make my box sound significantly better i wouldn't mind doing it.

Trixter
03-29-2006, 04:46 AM
ok...i didn't know that the front had an over hang...then yeah 10.25 + .75.

the only part that will be considered extra displacement is the piece that is currently in the box, the messed up piece. it would be the same as if you built the box correctly and simply added another piece inside the box. .06cu' will not make a difference. add the piece to the inner port wall and you will be all good.

just as fyi....

the port's volume is accounted for in terms of displacement, just like the sub. if your sub takes up .5cu' and your port .4cu' and the sub calls for 3cu' box then you need to make a box that is 3.9cu' total.

to figure out port displacement...
-the length of the port minus the front baffle (front already accounted for because you measure the inside of the box. usually the front baffle is an added .75" of port length which will not be counted.)
-the inner heigth
-the port width + the thickness of the inner port wall(s) (usually .75)

multiply these together and divide by 1728 to get the port's displacement.

thai_creeper
03-29-2006, 12:07 PM
cool, thanks again for all your help trixter ;)

Trixter
03-29-2006, 12:10 PM
no prob, man...need anything give a shout.