Custom Sub Box

pektel said:
Shipping a box is insanely expensive.

And to 04SCTLS, I don't think plywood would be a good option for a box. I would think something with a more consistency in density would be better. Also, I wouldn't want the box to be completed, turn it on, and have a section of it rattle because of delamination. MDF is definitely the way to go for a box (if not using fiberglass)
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Actually shipping a box isn't as bad as you might think. I ship several boxes a week through UPS.

I've shipped boxes from NY to CA and many places in between. Largest box I shipped was 48x20x20 and weighed over 100lbs and it only cost me $96 from NY to the midwest.


Also MDF or Birch ply are the materials of choice. Birch ply is about 2x as much as MDF (at least around here) but is also quite a bit lighter and much easier on your tools.
 
Quik LS said:
not to pile-on to the thread but - here is the thread from my enclosure. We measured the interior space and how that compensated for the speaker curve.

http://www.lincolnvscadillac.com/showthread.php?t=10731
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Well if were going to do that.

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One thing to keep in mind is that if you fire the subs to the rear and block the opening behind the rear seats and rear shelf you are blocking the bass from entering the cabin easily
 
My box has more trunk space than Quicks or SPYs.
Also you can lift the trunk tire well cover where it hinges.
Since I already had the 12s I built it with that in mind too.
The vents thump good into the car but I'm still sorting out
things with these high inputs off the door speakers.
 
sure - not poking holes at you, just adding options - we all can get to the spare tire....

the box really should be 'tuned' to assist the frequency response curve of the particular subs you plan to use. I am using 2 Sony 12" sub with a particular curve response unique to them. Just like porting - the hole size depends on the air mass you need to tune for - it's not simply a hole to let noise out.
 
My box was only about 30" wide, I didn't use the space where it bumps up on the sides.

Mine also got rid of the cover over the spare tire and I built a false floor to hold my amps, but it was easily removeable if you needed to access the spare or battery.
 
Quik LS said:
sure - not poking holes at you, just adding options - we all can get to the spare tire....

the box really should be 'tuned' to assist the frequency response curve of the particular subs you plan to use. I am using 2 Sony 12" sub with a particular curve response unique to them. Just like porting - the hole size depends on the air mass you need to tune for - it's not simply a hole to let noise out.
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we all can get to the spare tire....
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Not without removing your box.
I still have more trunk space than you.
Like I said this box has maximum size with minimal loss of trunk space
which is the best for me.

I like to make it up as I go along.
Now that it's done I'll calculate the volume.
I was looking on ebay and a 2 x 12" box that would fit the LS had a volume of 2 cubic feet, whereas the largest big box had 4 cubic feet.
This one will be probably just over 3 cubic feet which is good.
I'll worry about tuning it when I upgrade the rest of my stereo which is still mostly stock.
Right now the vents are handy for moving it around in the trunk...
 
Now the members have a choice of 3 box designs to chose from so everybody's happy :D :) :F :I
 
dude - please, do not throw stones - why do you think that? I can open my tire lid with out removing my box. I also can remove my box, and disconnect everything quickly - so that I can dump the weight when I race.

Tuning - is compensating for frequency response issue with the particular speakers you chose. Just like porting - the size of the hole relates to the mass of the air plug, which then relates to the frequency it will best vibrate at.

right?
 
Quik LS said:
dude - please, do not throw stones - why do you think that? I can open my tire lid with out removing my box. I also can remove my box, and disconnect everything quickly - so that I can dump the weight when I race.

Tuning - is compensating for frequency response issue with the particular speakers you chose. Just like porting - the size of the hole relates to the mass of the air plug, which then relates to the frequency it will best vibrate at.

right?
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When tuning a box you need to know the net vol of the enclosure and the freq you want it tuned to. You change the tuning by using different size/length "ports".

Take my box as an example, it is 2.5ft^3 and my desired tuning was 33hz. I decide that a 4" round port was large enough so that I wouldn't get "port noise" (chuffing noise from the port when not enough port area is used) and from there I calculate the length needed to achieve my desired tuning.

There are several calculators available to help with these calculations as well as producing frequency graphs to show how your subs will react to different tunings.

The point of tuning a box is to get the desired sound from it, whether it be a totally flat response or a peak at a certain frequency.
 
There are several calculators available to help with these calculations as well as producing frequency graphs to show how your subs will react to different tunings.
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any links?
 
Quik LS said:
dude - please, do not throw stones - why do you think that? I can open my tire lid with out removing my box. I also can remove my box, and disconnect everything quickly - so that I can dump the weight when I race.

Tuning - is compensating for frequency response issue with the particular speakers you chose. Just like porting - the size of the hole relates to the mass of the air plug, which then relates to the frequency it will best vibrate at.

right?
Click to expand...

I'm not trying to throw stones.
Your box looks like it's in the way of getting to the tire well so I'm assuming you have to remove it to get under the cover.
There weren't enough photos in your older post to see your box more exactly and such so perhaps I'm mistaken.

My box is big and does have the most trunk space.
I'll wait until it's working properly to see how it sounds to me with the vents.
I'm not having much confidence in these high voltage off the door speaker inputs.
Maybe I will just get a new GPS Stereo head unit sooner than later.

I can just fit up some 3" abs plastic pipe on both sides for ports in the factory 6 x 9 locations if I'm not happy with the sound.
 
04SCTLS said:
any links?
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The only free one I know of is WinISD but it's not something you can just download and start using right away, there is a lot that goes into using it the correct way.

If you want to check it out go to www.linearteam.dk

I use this along with Bass Box 6 Pro

There are some other free basic box calculators but they won't do the freq graphs and they are not known to be the most accurate

If you just want to calculate the length of a round port go to www.psp-inc.com and click on their calculator. Very basic, accurate and free but doesn't work for slot ports.
 
If you just want to calculate the length of a round port go to www.psp-inc.com and click on their calculator. Very basic, accurate and free but doesn't work for slot ports.
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SPY
Thanks alot for that.
It's all I need.
Graphs are nice but not really nessesary.
Changing from slots to round holes is no big deal for me.
There's enough room for 2 ports per side at the factory locations
if need be.
 
right - not picking on your construction at all - just offerring that the box design has more to do with maximizing and tuning the sound within the space confinment of the area you are building in.
 
If I want to keep the slots I suppose I could take their area and convert that into a circle to get a port diameter for the calculator.

That would give me a length I could make out of fiberglass.
 
Or you could just cap those holes you are calling 'vents' off with some MDF baffles and just put in an aero port or two if you want both sides.



This is a picture of one assembled

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Just buy one of these and cut it to the length you need and presto... instant aeroport with zero 'port noise'
 
Just buy one of these and cut it to the length you need and presto... instant aeroport with zero 'port noise'
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Ok I see flared at both ends.
Alright I'll calculate this out and order 2 ports tomorrow.
I don't have as much depth as the one in your picture.
 
Yup that is where I buy mine. And yes I would go with some 3" ports since you are wanting to do both sides. Then you can use that PSP calculator to determine what length to cut each tube
 
Ok I ordered 2
3" flared ports.
They'll be here next week.
Using my pattern drawings I seperated the box into 3 sections.
The bottom. middle, and top.
I came up with 3.5- 3.7 cu ft depending on how you account for the thickness of the MDF.

I have a maximum depth of 9" I can go and the calculator put me at about 6" with 38 hz as the frequency.
 
According to these charts that came with my Rockford 8" 200 watt rms each subs for my Camaro 3.6 cu/ft (1.79 x 2) is optimum size for 2 12" subs in a vented enclosure.

I always was a good guesser :D

Sealed Box.jpg


Vented Box.jpg
 
I'm not really sure but I think each manufacturers speaker will be different on what amount of space would be optimum, so that chart might not really work for the Audiobahn your using.

Either way the design looks really good and I hope it works out well for you, keep us updated on whats going on with it.
 
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