Tutorial And Link For The Calculator I Use

[andym85]

I figured I would do a sort of a tutorial of how I use my excel calculator so that there is no confusion. Just to warn you all, its kind of lengthy.

before you download:

plz make this change to two equations:

copy and paste the following formula into cell H17 =if(a21<=L17+(j7-b18),A21-L17,j7-L17)

copy and paste the following formula into cell I30 =if(a18=0,c25,a21+a9)

the first equation was changed b/c it kept giving you a -.75 output for L2 (which is b/c i tried to incorporate the thickness of the baffe into the tuning equations...and it didnt work there)

the second equation was changed to incorporate the thickness of the baffle into the actual legnth for the tuning equatin

Here is a link to it (if it doesn’t work then I can email it to ya)

http://www.mediafire.com/?2ypo0iymlum

And here is what it looks like

First off if you all don’t give me a specific volume and tuning for the enclosure then I always try and go to the manufacturer’s website to try and find enclosure and tuning recommendations, as well as the sub’s mounting hole and displacement. Unfortunately a lot of subs don’t have their displacement listed, but that isn’t too big of a deal.

In my opinion the spreadsheet is fairly self explanatory, but there are a few minor quirks to it. As you can see, the left side of the sheet is for inputs, and the right side is outputs, with a few exceptions.

-First I enter the number of subs and their displacement.

-Then the thickness of the wood is entered.

-Then the port dimensions are entered….and here is one of the small quirks of this calc.

*First: ALWAYS enter the smaller number for your port opening in the width box

(if you don’t then a few things will be off in the results)

*since the port dimensions are based on the depth of the box, whatever side the port is on needs to be entered as the depth, and this will not affect any other calculations as far as tuning, volume, and port displacement goes.

For instance say you have a box that is 10h x 15w x 20d:

*if your port was forwards or backwards then the dimensions will stay just like above. 10h 15w 20d

*if your port was on the top then you would have to enter the height in as the depth since that is the actual depth as far as figuring the port dimensions. You can just put the actual depth in the height box. 20h 15w 10d

*if your port is on the side then you would have to enter the width in as the depth and you can just put the actual depth in the width box 10h 20w 15d

-make sure you have all of the round port dimensions as 0 if you are doing a slot port and all of the slot port dimensions in if you are using a round port.

-if you are using round ports then just enter the number of ports, radius of one port, and the length of one port. When you are figuring tuning with multiple ports then you need to divide the net volume by the number of ports to figure the proper tuning. This calculation is automatically done within the spreadsheet.

Once you have all of that entered then the outputs will automatically be calculated.

-The inner dimensions may need to be adjusted depending on if you are doing a double baffle for instance.

-under the “port info” section: it shows you how much port area is needed for 12sq”/cubic ft and how much port area is need for 16sq”/cubic ft. then it shows what your actual port area is and how many sq”/cubic ft that is. The port ratio is simply the ports height/width and should not exceed 9.

-dimensions for port displacement: here is another small quirk with this calc. these numbers may need to be adjusted based on how your port is:

I.E. your port opening is 12”h x 5”w and u are using ¾”wood

please ignore all measurements in these 3 pics b/c they are just reference pics

*case 1: your port uses one box wall for a port wall like the picture below. Then

the dimensions for port displacement should be 13.5” x 5.75”

*case 2: your port uses 2 box walls for the port walls like in the picture below.

Then the dimensions for port displacement should be 12” x 6.5”

*case 3: your port uses 3 box walls for the port walls like in the picture below.

Then the dimensions for port displacement should be 12” x 5.75”

-bracing displacement must also be manually added.

HOW PORT LENGTH IS FIGURED

As you can see from the picture the length of the port is measured straight down the middle, NOT measured as the length of the wood used. The measurement begins at the opening (taking into account the thickness of the wood being used) and runs all of the way back ending half of the ports width off the back wall. Then it is measured from that point to the end of the wood.

End correction (end corr.) is half of the ports width and is figured automatically. L1+L2+end corr. should always equal the desired port length that you put in on the input side.

There is a gray area for port length that I haven’t been able to figure out yet. I will try to explain this issue, as I see it, as good as possible.

In the picture used above the ports width is 3”, L1 is 14.75”, and desired port length is 27”. Now the maximum L1 can be before it turns is 14.75”. so what if you want the desired port length to be 15”? when L1 makes its bend it stretches 1.5” (half the ports width of 3”) before you get to any wood used by L2. do you all see the problem there? If you don’t then I can try to explain it further….if you do then help me out if you have any input….

That’s about it!! I made a little snapshot to give a quick rundown of all the specs on the far right. If I left anything out or you want more info then let me know.

[EricM9104]

Nice tutorial.

Link doesn't work.

[andym85]

try it now!

[EricM9104]

Yay, link works. Now to have fun messing around in that, see what I come up with. )

[andym85]

Yay, link works. Now to have fun messing around in that, see what I come up with. )

just make sure u dont mess any major formulas up...some of them are kinda complicated...and i almost locked the cells that shouldnt be messed with but i didnt...have fun

[EricM9104]

just make sure u dont mess any major formulas up...some of them are kinda complicated...and i almost locked the cells that shouldnt be messed with but i didnt...have fun

Lol. Just in case, I made the file read-only so I can't save over it.

[Guest Nismofreak]

thanks....that will help me out alot!!!!

[Guest Nismofreak]

could you tell me if I did this right?

2 type r

tunning 32

1.3 cubic for each

[EricM9104]

Uhm, the spot where it says "displacement for one sub" means how many cubes of the box one sub takes up....

[Guest Nismofreak]

Uhm, the spot where it says "displacement for one sub" means how many cubes of the box one sub takes up....

yah I know