I mean Subwoofer Box Specs (not subwoofer). Well Skip helped me with these specs, not that I don't trust him , I just want to make sure they are the correct spec befor I go cut it and put it together today.

I calculated on

http://www.edesignaudio.com/bo...ented

for a custom vented cell program enclosure,

My max dimensions

A. 22"
B. 24"
C. 14"

32hz tuning freq

Interior Volume - Total 3.031cF - 85.8L

Displacement of the subwoofer is 0.19cuft

I calculated the port length on

http://www.psp-inc.com/psp-inc...r.cgi

I put in 3.0cuft, 32hz tuning frequency, 4 for port diameter (4" flared aeroports are what I'm using), number or ports I put 2 (using 2x4" aeroports), came out together to be 20.12" so my 2 ports are going to be approximately 10.06" long. My cutout dimensions are the box for 3/4" mdf is

24x17 front/back
24x22 top/bottom
22x14 sides

Does this sound right?

What is the internal cuft after everything is put together is what I'm curious too, I know it comes out less then 3.0cuft doesn't it?

 

Sides will be mounted inside, FCM stated it was incorrect, could someone help me out?

 

Let me know what sub you have and I'll stuff all that info into winisd and see if it's close to what you have.

 

2005 Resonant Engineering 12" XXX Subwoofer.

Sub Specs:

FS 27.0HZ
Re 1.9DVC
Qms 4.52
Qes 0.44
Qts 0.4
SD cm2 480
Vas 56.5 l
Xmax 1 way linear 32mm
BL 17.1
SPL 1W/1M 85.9
RMS 1600w
MAX 2500.w
Cutout 11 1/8
Displacement 0.19cu ft
Mounting Depth 8�
Weight 56lb
Sealed Enclosure .75-1.5 cu ft
Ported 1.6-2.5@34hz

 

So far FCM been helping, he replied with

Front and rear 24"x14"
Top and bottom 24"x20.5"
Sides 20.5"x12.5"

With 3/4" MDF that will give you 3.34cuft gross volume subtract driver and port volume from that for net volume, however I would use 1" MDF for the sides, all measurements stay the same except box volume is now 3.26cuft gross.

I want something around 2.5'ish cuft

Edit: I'm not sure how do I subtract the port volume (4" aeroported is what I"m using from Precision Ports)

 

For 2.5 cubes tuned to 32 hz, you will need 2 (4 inch) 23.5" long ports. To figure out how much volume the ports take up, you need to use (2 ports)(pi)(r^2)(h)/(1728 cu in/cu ft), which would be 2*3.14*2^2*23.5/1728 = .34 cu ft (both ports). The driver takes up .19 cu ft, so the total box volume would have to be (2.5)+(.34)+(.19)=3.03 cu ft. So the dimensions that FCM provided will work. The increased box volume will lower the tuning frequency a bit. Do you want the overall volume of the box to be 2.5 cu ft?

 

fcm: F/R 20"x14"
T/B 20"x12.5"
Sides 12.5"x20.5"
Is correct, attatch top and bottom to sides, then attatch front, seal all inside surfaces with fiberglass resin or wood sealer, silicon seams install back, seal and silicon back through sub mounting hole.
As I said I would use 1" MDF for the sides for strength, and more material to screw into, just add .5" to lenght of box.
That sub is going to need lots of power, you do not want the box to blow/fall apart.

So my final dimensions are

F/R 20"x14"
T/B 20"x12.5"
Sides 12.5"x20.5"

and my 2 (4" aeroports are only 17" max)

I went to http://www.psp-inc.com/psp-inc...r.cgi

and put in 2.5" cuft, 32hz frequency, 4" port diameter, and 2 ports and it gave me

Straight Length Port required 23.53
Flare Length Port required 24.53

I am using flared ports, so I just need to divide 24.53 by 2 and those are the length of my ports?
Anyways to home depot I go , getting some 3/4" MDF cutted. Thanks Guys..

 

Are the port dimensions you're giving me, those are the overall total for both ports correct? So for each port all I need is 12.26" length ports for each one? Anyways Be back in a bit, home depot I go.

 

No. The 24.5 would be the length of each port.

As you double the area of the port, you need to double the length. And since each port is half of your final area, each one needs to be the given length. If you don't believe me, plug in that you're using 1 port, and it will give you a lenth of around 12 inches. This isn't the same as using 2 ports of the same length (12 in).

Notice that your max dimension of your box is only 20 inches, while the port needs to be 24.5". And since your ports are only 17 inches long, you need to increase the box volume (to keep the same tuning), or the tuning frequency will be raised.

From my calculations, your overall box volume is 2.74 cu ft, then you have to factor in the volume of the ports (full length - .25 cu ft) and the volume the driver takes up (.19 cu ft). So your net box volume is 2.31 cu ft, and with full-length ports (17 in), the tuning will be at 38 hz.


Modified by 02 accord at 4:45 PM 8/19/2006

 

WTF!!! Each length of the flared port needs to be 24.5" long? Are the calculations from

http://www.psp-inc.com/psp-inc...r.cgi

Incorrect? Damnit I thought I had everything figured out...

blah I feel like quitting now, 38hz seems big on the high side for me...

 

Both of our calculations are correct, but when it says 24.5" for the length, it means the length of each port. You don't divide that by 2.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 02 accord &raquo;</TD></TR><TR><TD CLASS="quote">Both of our calculations are correct, but when it says 24.5" for the length, it means the length of each port. You don't divide that by 2.</TD></TR></TABLE>

Yeah but if you put 1 for number of ports, it calculates to

Straight Length Port required 10.30
Flare Length Port required 11.30

And putting in 2 comes out to

Straight Length Port required 23.53
Flare Length Port required 24.53

So I figured they calculate it for both ports together.

I don't get it, I'm going crazy, it's getting frustrated. And here I sit thinking geometry was easy!

 

Well I suppose I go start on cutting the mounting hole..

 

Great I just tried to put the pieces together and it seems as if they are not going together right....


My final cutouts are

Front/Back - 20" x 14"
Top/Bottom - 20"x12.5"
Sides - 20.5" 12"

What's the problem?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shyboy817 &raquo;</TD></TR><TR><TD CLASS="quote">

Yeah but if you put 1 for number of ports, it calculates to

Straight Length Port required 10.30
Flare Length Port required 11.30

And putting in 2 comes out to

Straight Length Port required 23.53
Flare Length Port required 24.53</TD></TR></TABLE>

As I already said, 1 port at ~11 inches is not the same as 2 ports at ~11 inches.
As you double the area of the port, you (approximately) double the length of each port.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shyboy817 &raquo;</TD></TR><TR><TD CLASS="quote">Great I just tried to put the pieces together and it seems as if they are not going together right....


My final cutouts are

Front/Back - 20" x 14"
Top/Bottom - 20"x12.5"
Sides - 20.5" 12"

What's the problem?</TD></TR></TABLE>

Using 1" or 3/4" MDF? Either way, if your front/back and top/bottom pieces are all 20 inches wide, the 20 inch sides match up, and there's no way that the sides can be 20.5 inches. For the sides, 12x12.5 would make sense tho (assuming 1" mdf).

 

3/4" MDF wood.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shyboy817 &raquo;</TD></TR><TR><TD CLASS="quote">What's the problem?</TD></TR></TABLE>

The side pieces.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Front/Back - 20" x 14"
Top/Bottom - 20"x12.5"
Sides - 20.5" 12"</TD></TR></TABLE>

I'm assuming the box is 20" wide, 14" tall, so the front/back pieces would go top to bottom. The top/bottom pieces would fit in between the front/back. And then, the sides would fit in between everything else. So a size for the sides that will work is 12.5"x12.5".

Or if you put the front/back pieces in between the top/bottom, the sides will need to be 14"x11".

I hope I got the numbers right.

 

I wonder how FCM got 20.5"x12" for the sides. I have a headache now, I think I'll finish it tomorrow, I'm lost now. So I could cut the sides at either 12.5x12.5 with the top and bottom inside of the front and back, and the sides will be inside of the front back top and bottom?

 

Well I end up cutting the sides to 12.5x12.5 and they fit inside. I threw the box together and took some pictures, the box seems to be very very small. It's 20" width, 14" height, and 14.25" depth..does not sound right. Hmmm? This cannot be right..? I figured it's suppose to be a lot bigger then this......ARGH..please do not tell me I just wasted money on wood and it is not right..........

Pics

 

 

So just f'n great, I put in the dimensions that I measured on that box, 20"width, 14"height, 14.25"depth,

http://www.edesignaudio.com/bo...ealed

sealed

Current Interior Volume - Total
1.706 cF - 48.3 L

Just ******* wow, I done wasted money on wood, time, somehow got the whole thing wrong, what the hell did I do wrong? I'm going crazy, things can't get any f'n worse, I thought the given dimensions were correct...........