ok i have decided to go with 2 more 15s for now, if i dont liek then i may try the 2 12s as swez mentions previously. i need some help figuring how much cubic feet im going to have to each sub, the front and back pieces are 48inches by 24. the top and bottom are 48 by 25. the two sides are 24 by 25 as well as the middle divider. and then the two pieces that divide each half diagonally are 24 by 26 inches. on the sub requirements is that internal or external volume. if im doing the math corretly i take 48x24x25=28800, then divide that by 12x12x12=1728. that comes out to 16.66... thats the external without taking away the dividers or the thickness of the wood. can somebody help me out here, im using 3/4 mdf wood. or explain how to subtract all that and ill do the math. the box will probably turn out horrible but atleast im learning, its the first box i have attempted to build. maybe ill suprise myself
Replies (6)
ttocs on 09/17/2003 11:37:50
that would be about right. 16 ft cubed is a bit much I would imagine. What is the recommended airspace per speaker? What is the volume the magnet and assembly take up? When I build a box, I find two of the demensions(height and depth generally) and then use algebra(who knew it had a real life use?) and solve for the third using the airspace requirements + the assembly volume to find the third dimension(depth).
If you want to find the internal demensions, I normally subtract 1.5"s from the measurements to compensate for the thickness of the wood.
compvr15s on 09/17/2003 21:18:47
the subs can be used in upto 5.2 cubic feet sealed boxes. and 16 divided by 4 sub woffers will net somwhere between 3.0 and 3.75 cubic feet per sub. the specs say the displacement is 243.6 cubic inches... is there a certain amount of space that is needed behind the subs. once i get the box build and the subs in place the back of the speakers will not have an enclosure like most, the inside of the box will be a triangle so the back will be facing the farthest away corner of its enclosure will this have an affect on the subs. most boxes i have seen the speakers is placed with the back of the sub going to a flat piece. i know i dont explain well but oh well if the box dont work out, i can always just make another one that will hold the other 2 15s and put it in the trunk and use the orignal 2 15s in the box i have in teh back seat now. thanx alot
Swez on 09/18/2003 07:48:09
The max recommended sealed for Comp VR 15's is 5.2 cf/sub. The min is 1.8 cf. As you already know, the larger the box, the deeper and louder the low bass will be. If you want loads of boom... then a 30+ cf will be needed for 4 subs.
I suggest that you carefully consider your goals and space available for this application. A 3.0-4.0 cf/sub enclosure would net very good results. This will net good low bass and decent punch as well. This means about 18 -24 cf enclosure (externally). That one huge box pal and it will weigh more than 200 lbs. Think about that one carefully... how are you going to load this box into this new vehicle??? Gotta a few BIG GUYS to help?
Not only that, this extra weight will definiely affect the suspension and handling charachteristics of this smaller car. Not to mention your total lack of cargo space with the subs installed.
In short, please do consider the dual 15's as your low bass drivers and maybe a pair of 10's/12" for more punch bass. Much smaller enclosure and you'll have both deep bass and punch as well... in a much smaller package.
Swez
Tray on 09/18/2003 09:04:52
Well, you say you used 3/4 MDF correct? And those dimensions are the outside dimensions right?
Well, then to find your air space, you take the interior length (46.5") x interior width (23.5") x interior depth (22.5").
This nets you 24586.875 sq inches.
Then to find the area of the dividers, length (22.5") x width (23.5") x depth (0.75") which is 468 sq inches each.
24586.875 - (468x2) = 23650.875 sq inches.
23650.875 / 1728 = 13.69 sq ft
13.69 sq ft / 4 subs = ~3.42 sq ft per sub.
DINGALING on 09/18/2003 13:24:34
wow. you must have a pickup. or are you planning on yanking out the back seat of your car? or are you going to lose a bench out of a suv? i put in a dual 2 cubic foot enclosure into my civic. i litterally had to pound that box in. more sweat went into putting it into the car than building it! mine was 4 cu ft total. it weighs atleast 80 pounds. ATLEAST. i don't know what u are using for building materials, but if you use mdf, that junk will be in the hundreds of pounds category. especially 30+ cf ??? omg. on the plus side, my box has made my car a little quicker on the turns... :)
-DINGALING
compvr15s on 09/18/2003 21:11:28
its in my 88 grand prix, i removed the back seat. i am using mdf 3/4 inch. its going to take over 2 4ftx8ft sheets to complete the box, plus the 4 15s. im sure it will weight probably 175 or 200 lbs. its good becuse then no one person can remove it. well even a few people because im going to have to take out the driver seat and maybe even the driver door off. but its a fun experiment and im enjoing the time i spend with my brother working on it.
Replies (6)
ttocs on 09/17/2003 11:37:50
that would be about right. 16 ft cubed is a bit much I would imagine. What is the recommended airspace per speaker? What is the volume the magnet and assembly take up? When I build a box, I find two of the demensions(height and depth generally) and then use algebra(who knew it had a real life use?) and solve for the third using the airspace requirements + the assembly volume to find the third dimension(depth).
If you want to find the internal demensions, I normally subtract 1.5"s from the measurements to compensate for the thickness of the wood.
compvr15s on 09/17/2003 21:18:47
the subs can be used in upto 5.2 cubic feet sealed boxes. and 16 divided by 4 sub woffers will net somwhere between 3.0 and 3.75 cubic feet per sub. the specs say the displacement is 243.6 cubic inches... is there a certain amount of space that is needed behind the subs. once i get the box build and the subs in place the back of the speakers will not have an enclosure like most, the inside of the box will be a triangle so the back will be facing the farthest away corner of its enclosure will this have an affect on the subs. most boxes i have seen the speakers is placed with the back of the sub going to a flat piece. i know i dont explain well but oh well if the box dont work out, i can always just make another one that will hold the other 2 15s and put it in the trunk and use the orignal 2 15s in the box i have in teh back seat now. thanx alot
Swez on 09/18/2003 07:48:09
The max recommended sealed for Comp VR 15's is 5.2 cf/sub. The min is 1.8 cf. As you already know, the larger the box, the deeper and louder the low bass will be. If you want loads of boom... then a 30+ cf will be needed for 4 subs.
I suggest that you carefully consider your goals and space available for this application. A 3.0-4.0 cf/sub enclosure would net very good results. This will net good low bass and decent punch as well. This means about 18 -24 cf enclosure (externally). That one huge box pal and it will weigh more than 200 lbs. Think about that one carefully... how are you going to load this box into this new vehicle??? Gotta a few BIG GUYS to help?
Not only that, this extra weight will definiely affect the suspension and handling charachteristics of this smaller car. Not to mention your total lack of cargo space with the subs installed.
In short, please do consider the dual 15's as your low bass drivers and maybe a pair of 10's/12" for more punch bass. Much smaller enclosure and you'll have both deep bass and punch as well... in a much smaller package.
Swez
Tray on 09/18/2003 09:04:52
Well, you say you used 3/4 MDF correct? And those dimensions are the outside dimensions right?
Well, then to find your air space, you take the interior length (46.5") x interior width (23.5") x interior depth (22.5").
This nets you 24586.875 sq inches.
Then to find the area of the dividers, length (22.5") x width (23.5") x depth (0.75") which is 468 sq inches each.
24586.875 - (468x2) = 23650.875 sq inches.
23650.875 / 1728 = 13.69 sq ft
13.69 sq ft / 4 subs = ~3.42 sq ft per sub.
DINGALING on 09/18/2003 13:24:34
wow. you must have a pickup. or are you planning on yanking out the back seat of your car? or are you going to lose a bench out of a suv? i put in a dual 2 cubic foot enclosure into my civic. i litterally had to pound that box in. more sweat went into putting it into the car than building it! mine was 4 cu ft total. it weighs atleast 80 pounds. ATLEAST. i don't know what u are using for building materials, but if you use mdf, that junk will be in the hundreds of pounds category. especially 30+ cf ??? omg. on the plus side, my box has made my car a little quicker on the turns... :)
-DINGALING
compvr15s on 09/18/2003 21:11:28
its in my 88 grand prix, i removed the back seat. i am using mdf 3/4 inch. its going to take over 2 4ftx8ft sheets to complete the box, plus the 4 15s. im sure it will weight probably 175 or 200 lbs. its good becuse then no one person can remove it. well even a few people because im going to have to take out the driver seat and maybe even the driver door off. but its a fun experiment and im enjoing the time i spend with my brother working on it.
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