Sealed sub box dimensions calc. and reduction help?!?!?

[Z1truth 0]

Hey guys, can someone with knowledge I don't have give me a hand PLEASE! I'll be real grateful! I bought my 2 10" FI D2 Q's for this box for my 350Z which has a advertised inside dimensions that produce .70cuft per chamber.

Scott's advertised cuft spec for these subs is .20 -.60cuft. So I'm about .10cuft over.

First a couple of questions. (getting old sucks....memory shot! LOL!)

#1. I think Scott said he wanted the .20 - .60cuft space for the box PRE sub installation???? So in other words don't use the sub displacement itself in the final cuft #. The box without the sub should be .20 -.60cuft. Does that sound right?

#2. Obvisously I want the BEST possible performance from these subs, so I'm thinking of adding a Block inside in the back of the box to take up .10cuft of space to get the optimum space. Will this be OK? (PS decimal in wrong place in pic)

Like I said, I'm hoping just putting a 9.75" X 4" X 5" block screwed to the back will be good enough fix ?????? (dimensions = 195cu/in", a little more than .10cuft which = 172.8cu/in")

What do you guys think???????

#3. Here are the sub box inside dimensions. The width of each chamber is 9.750" wide which is the dimension you can't see in the picture. How do you figure out cuft with dimensions like these?????????? Anyone know?????? Just want to double check the advertised specs!

(Please excuse my chicken scratchin photoshop writing guys)

And again from this HUMBLE noob......thank in advance for the help!

Edited March 25, 2007 by Z1truth

[///M5 2,833]

I don't think I'd do anything without listening to them as is. You are actually in the range as the sub will take more than .1cuft. You will probably like the bigger enclosure.

[theabunai 3]

#1. I think Scott said he wanted the .20 - .60cuft space for the box PRE sub installation???? So in other words don't use the sub displacement itself in the final cuft #. The box without the sub should be .20 -.60cuft. Does that sound right?

No the sites specs are for air space AFTER all displacement

so say your box is .70 cu ft

when you drop the sub in the actual cuft is going to go down by using the following formula

.70 - 0.12 (displacement) so you get a final airspace of .58

this means if you want the box to be a final airspace of say .60 then you design it to have an arispace without the sub of .72 so when the sub is dropped in you get the following

.72 -0.12 = .60 cu ft

So if your box is .70 cu ft

with displacement

.70 - 0.12 = .58cuft that puts your RIGHT in range of the best possible air space for the subs....

Edited March 12, 2007 by theabunai

[Z1truth 0]

Thanks guys! Highly appreciated!

Like I said my memory is Shot! I could of sworn Scott said .20 - .60cuft space for the box PRE sub installation. If you guys are right tho, I can just plop them in and go.

Does anyone know how to make sure the dimensions on this box = .70.

I can do 12 X12 X 12=1cuft.......but those multiple dimensions.........yikes!

[theabunai 3]

http://www.leeric.lsu.edu/bgbb/7/ecep/math/n/n.htm

http://mathforum.org/library/drmath/view/69826.html

That link i have in my bookmarks for building boxes

I hope it helps you

Edited March 12, 2007 by theabunai

[Z1truth 0]

http://www.leeric.lsu.edu/bgbb/7/ecep/math/n/n.htm

http://mathforum.org/library/drmath/view/69826.html

That link i have in my bookmarks for building boxes

I hope it helps you

Well....this box isn't quite a triangular shape or rectangular either. If you split the 2 sections ......nahhhhhhh! This is a tough one for this country bumpkin! Thanks for the links tho...bro!

[Fi Car Audio 64]

Im getting red Xs for the pics right now, so I cant really check the enclosure sizing. But if its a trapezoid, with the top and bottoms being different sizes, but width and height being equal, then you simply do W X H X ((Top + Bottom)/2) in inches... then divide by 1728 to give you the volume in cuft.

I absolutely love the box. That has to be the nicest drop in Ive ever seen... and like you said, he is doing quite a bit of business with those.

At .7cuft per chamber, you are looking at .58 after displacement which will yield a .59 Qtc. Most people will find this too low for their tastes, although I tend to like .7 and lower Qtc sealed alignements. Very smooth and natural sounding. Shrinking things down to .33 cuft yields a .71 Qtc which is maximally flat. Like I mentioned before... most people like a higher Qtc .9-1 since it tends to emphasize/exxagerate things a little more. But at that point, you would really be choking the enclosure down.

As ///M5 mentioned, drop them in as is and listen. You might find yourself liking them in the standard space (if you have a very solid midbass up front). Noting your initial impressions of them, then listening for a couple of days, see if you need things to "tighten" up some or not. If you do, you can shrink the enclosure up by adding either solid layers of MDF (which weighs a bit and Im figuring in that car you dont want to load it down), small empty MDF boxes (1/2" MDF is plenty for something like this). Large pieces of closed cell foam (syrofoam blocks would be fine and add minimal weight), or whatever you can stuff in their that is "solid" to take up space. You are in the opposite position from most people. Usually people are trying to stuff too large of a driver in too small of a space and dealing with a high Qtc. You can lower the Qtc some by using polyfill to stuff the enclosure and this maxes out at 1 lb per cuft and about a 15% increase in perceived enclsoure volume increase and the resulting Qtc change.

If you have any other questions, let me know.

Thanks,

Scott

[Z1truth 0]

WOW! Great info Scott! So you couldn't see the pics with the dimensions????? Does that calc work even if it is a one sided trapezoid. Meaning the bottom is long and flat end to end and the top is 6.25 flat parallel to the bottom then slopes down a length of 9.75 to a back wall of 4". If I use your calc and don't use the 9.75" slope or back wall 4" spec. ,just the sub side face height 10.5" X the 9.75" width X 11.125"(the 16" bottom + the parallel 6.25 top divided by 2) then divide everything by 1728 = .66cuft. for chamber cuft.

Does this sound right! Anyone hatin me yet! LOL!

Enquiring minds want to know! I'm just learning here guys!

By the wayTHANK YOU

Edited March 13, 2007 by Z1truth

[HawaiianBassHead 0]

WOW! Great info Scott! So you couldn't see the pics with the dimensions????? Does that calc work even if it is a one sided trapezoid. Meaning the bottom is long and flat end to end and the top is 6.25 flat parallel to the bottom then slopes down a length of 9.75 to a back wall of 4". If I use your calc and don't use the 9.75" slope or back wall 4" spec. ,just the sub side face height 10.5" X the 9.75" width X 11.125"(the 16" bottom + the parallel 6.25 top divided by 2) then divide everything by 1728 = .66cuft. for chamber cuft.

Does this sound right! Anyone hatin me yet! LOL!

Enquiring minds want to know! I'm just learning here guys!

By the wayTHANK YOU

to be honest I don't think you need to figure cubic footage... the guy sells it at .7 then it's more than likely close. a little large or small isn't going to cause problems for the driver, it'll just give different sounds... smaller more natural/smoother, larger more boomy. for lack of better words... put them in, see if it needs to be tighter/punchier, if it does shrink it down a little.. me personally, I'd use 2" or smaller wood dowels to brace it front to back side to side top to bottum. no doubt in my mind it'll flex since it's single layer and these subs have potential to move alot of air and with force... so I'd imagine the box will have very light flexing that would go away with bracing and to get cylinder volume you do (3.14r)^2(h) piexradius(squared)x height/length IF you REALLY think the dowels would set you overboard on volume... but I think you're at optimal range a good mix of sq and spl

[Z1truth 0]

and to get cylinder volume you do (3.14r)^2(h) piexradius(squared)x height/length IF you REALLY think the dowels would set you overboard on volume...

OH MY GOD! MORE MATH! I QUIT! ROFLMAO!!

Just kidding......I can think my way into procrastination because of stupid perfectionism till the cows come home! I'm just droppin them in and away we go!!!!!! I like the dowel bracing mod idea tho! Thanks King Cumonawanalaya! j/king! LOL! Thank you HawaiianBassHead!

Edited March 13, 2007 by Z1truth

[theabunai 3]

In all honesty

I don't think the ear can hear a difference in such little change in air space... A meter may but not the ear....

[Z1truth 0]

In all honesty

I don't think the ear can hear a difference in such little change in air space... A meter may but not the ear....

Yeah your right, I just tend to WAY over analyze things in order to get it right the first time around! Thanks bro!

[theabunai 3]

Hey z1 don't worry mate...

I'm the same way LOL