# Subwoofer box/ Need Help



## B.Beesmer (Apr 15, 2013)

Hi guys, I am new here. i will get straight to the point, i have a 12'' sub woofer, and the box it was in had to tweeters in it. so i used a sawzall to cut it. i have a rough cut right now, will be posting pics here soon, and i was wondering what i could use to make the cuts more accurate so i could fit a new piece of wood and attach it.. any tips or ideas? all ideas are helpful thank you


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## jharris2 (Jul 9, 2012)

Photos?


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## B.Beesmer (Apr 15, 2013)

just posted them.. hope they help


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## B.Beesmer (Apr 15, 2013)

i was thinking maybe a leveler and a more precise cutting tool as a thought.. not sure on what to really use..


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## Da Aardvark (Oct 11, 2012)

You can use a straight edge and a circular saw with a fine blade so it doesn't chip up too bad.
Get the sawdust out of it afterwards. Insulate the top properly as well as the sides....Pink fiberglass os ok.


The original box size was designed for the acoustics of the speaker. Every speaker has a optimum cavity space (in square foot), which the speaker needs for proper resonances and movement.
I think your box is too small for low bass sounds, and you will likely get less boom for the buck. Sorry to tell you that, but I've built a handfullof speakers and see the cavity size as a problem. If it is a good quality speaker, consider making another enclosure.
I don't have my speaker design data available or I would size an enclosure for you whenI know the brand and details on the actual 12" speaker.


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## woodnthings (Jan 24, 2009)

*router? circular saw?*

I would use a framing square to mark all four sides using the front as a reference or starting surface. If you can cut to a line accuractely... probably not.... then a T square guide to reference the tool against would be best. 
http://www.popularmechanics.com/home/reviews/4283497

OR
http://www.ebay.com/itm/Kreg-KMA260...357?pt=LH_DefaultDomain_0&hash=item1c2f99808d

OR make one:
http://www.todayshomeowner.com/video/circular-saw-crosscut-guide/

A "speed square" like this is a useful a tool to have in your collection for making square cuts across boards. It can do much more but that's another subject.


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## Da Aardvark (Oct 11, 2012)

Also, you could slap a top on it and use 1/4 round trim to hide the cuts.


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## Phaedrus (Jan 18, 2012)

Well, there are lots of ways to do this, though some are easier than others. A more important question for us to help is this: What other woodworking tools to you have at your disposal?


A sawzall is really a demolition tool. By definition, it is a quick and dirty tool. Something with a round blade will be your best bet, if available (circular saw, table saw, etc). 

What are your plans after you get a straight cut? How do you plan to attach the top? Is this going to live in your home or in your car?


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## pidaster (Feb 22, 2013)

That kicker sub didn't likely come packaged in that box. Not all boxes will match the sub for the vehicle it must fit in. If this is as big of a box as you can use, go for it. I'd close off that port hole as it will operate better in a sealed box for a smaller enclosure.
Now on to your question. When I have to chop a box down like that I run it through a table saw with the blade just high enough to cut through one board. Flip it over to each side and run it though. Cut you another board to fit inside or to fit outside and glue and nail/screw.


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## B.Beesmer (Apr 15, 2013)

well thank you all for the help, and the subwoofer is a 12'' Kicker competition sub woofer.. and it did not come packaged in the box it is in now, and my tools are a sawzall, filer, leveler, tape measure , trying to get a sand block. and i am trying to find someone with a table saw..


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## B.Beesmer (Apr 15, 2013)

and after i get the straight cut that is level with all four side i plan on slapping on a 3/4 inch piece of wood, clamping it down and caulking the inside of it, let it sit for 12-24 hours, then test the waters, and fix any errors from there.. and i plan on having this is my room for the time being then after i get my new amp i plan on putting it back in the car.


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## woodnthings (Jan 24, 2009)

*not so fast there....*



B.Beesmer said:


> well thank you all for the help, and the subwoofer is a 12'' Kicker competition sub woofer.. and it did not come packaged in the box it is in now, and my tools are a sawzall, filer, leveler, tape measure , trying to get a sand block. and i am *trying to find someone with a table saw*..





B.Beesmer said:


> and after i get the straight cut that is level with all four side *i plan on slapping on a 3/4 inch piece of wood*, clamping it down and caulking the inside of it, let it sit for 12-24 hours, then test the waters, and fix any errors from there.. and i plan on having this is my room for the time being then after i get my new amp i plan on putting it back in the car.


To make straight cuts (X4) on the table saw will be difficult because you don't have a straight reference edge to ride along the fence.
A circular saw and guide will be the easiest and safest and give a clean, square to the surface, cut. 
Start across the front, then insert the blade in the kerf you started with and wrap around the sides using the guide. Same for the back/last. It would take 10 minutes with a circ saw, guide and you'd be ready fro your 3/4" plywood which will need to be cut to size as well. Don't be afraid/ashamed to ask someone for help on this. Use a good construction adhesive like Liquid nails, and you might consider corner blocks also. If this is just temporary, then "slap" is probably OK then. :laughing:


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## B.Beesmer (Apr 15, 2013)

okay well i found a circular saw that worked nicely to tidy up the edges, had to cut a little more off but it worked great, took the tips and help to the best i could and i have it glued and drying as i type.. thank you all for the insight and i will be using this forum a lot, for i have plenty of projects to come..


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## B.Beesmer (Apr 15, 2013)

also i will post a pic or two of the box with sub in it done and dried tomorrow, after i paint and tidy up the glue and what not, so please feel free to see it complete as all your tips and helpful insight was used to make it happen.. you guys are awesome, hope your days go good.


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## Da Aardvark (Oct 11, 2012)

I'm telling ya.
Cab't size is too small.


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## B.Beesmer (Apr 15, 2013)

we shall see, im hoping not.. if so i will run to hardware store and just make a new one from scratch, seeings as i have a better know how of what to do..


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## woodnthings (Jan 24, 2009)

*couldn't he use a tuned port?*

When the volume is too small I understand a tuned port will work?

http://www.ehow.com/how_5953267_build-tuned-port-speaker.html


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## woodnthings (Jan 24, 2009)

*Maybe a tuned port?*



pidaster said:


> That kicker sub didn't likely come packaged in that box. Not all boxes will match the sub for the vehicle it must fit in. If this is as big of a box as you can use, go for it. I'd close off that port hole as it will operate better in a sealed box for a smaller enclosure.
> Now on to your question. When I have to chop a box down like that I run it through a table saw with the blade just high enough to cut through one board. Flip it over to each side and run it though. Cut you another board to fit inside or to fit outside and glue and nail/screw.


See post above. I don't know anything about acoustics, but from building several bass reflex enclosures way back when, I think the port sized must be tuned to the resonant frequency of the speaker or some such thing...


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## pidaster (Feb 22, 2013)

woodnthings said:


> See post above. I don't know anything about acoustics, but from building several bass reflex enclosures way back when, I think the port sized must be tuned to the resonant frequency of the speaker or some such thing...


I've been in the audio business for the last 6 years and have been dealing with it for decades. Newer speakers don't function quite like the old ones. There are subwoofers that can function properly in 0.5 cu inch of air space and jam. Most 12" subwoofers function in about 1.2 cu inch. To move to a ported box you need to start with a 1.5 cu inch box minimum. Some take up to 5 cu inch. A tuned port will definitely get you better sound but that requires building from scratch and usually a larger size box. 
That's probably a basic Kicker comp and they don't require much airspace.
If I have the right model that I think this sub is, it requires a minimum of 1.25 cu inch and a max of 3.5 cu inch sealed box.
Vented box is minimum of 1.75cu in to a max of 2.25 cu inch.

Woodnthings, if you are talking about the reverse fire vented boxes that was extremely popular in the 90's, those did have to be tuned differently but they sucked no matter what.


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## jigs-n-fixtures (Apr 28, 2012)

A single bit axe. Apply the blunt end to your forehead. 

Then do a search on google for articles on speaker cabinet design. You cabinet appears to be undersized for the speaker. There is a lot of science underlying speaker design. Study it for a while, then you might stand a chance of coming up with something that doesn't just distort to the point it hurts to listen to it.


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## Da Aardvark (Oct 11, 2012)

Tuned port will free up the movement of the sound but the tuning then is for a specific frequency and that frequency is a cancellation wave of the one going out from the speaker face since it is ~180 deg out of phase.. That is a science a new builder should probably avoid. 

If that 12" is a "Kicker" (or whatever brand) contact the company and get the specs. There is a specific cabinet volume (in sq ft) that will optomize the sound and then if you want to further accentuate a specific frequency you tune the box size up (for deeper bass) or down (for the higher freq's the speaker produces) to meet your specific tastes. (I'm being very vague and giving an overview here and have not even talked about crossover circuitry)
You won't realize the speakers potential until you dial in the acoustics of the box.


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## liquid6 (Feb 15, 2011)

pidaster said:


> Woodnthings, if you are talking about the reverse fire vented boxes that was extremely popular in the 90's, those did have to be tuned differently but they sucked no matter what.


Whoa, does this bring me back to my high school days. I had one of those reverse fire boxes in my car. I believe they were called bandpass boxes and I had two Targa 10" subs powered by some amp. I later upgraded to a customer enclosure for 3 Kove KLD-12in subs powered by a Rockford 225.2 amp (which I still have and still works). 

By doing a quick search, that looks like a Kicker (obviously) Classic CompVR speaker. According to the manufactures website, the minimum sealed volume is 1 cubic foot. The maximum is 4.6 cubic feet. 

Judging by the size of the speaker, I'm guessing that box is about 22 in tall, 10 inches deep and 14/15 inches wide. By my calculations, that box falls right into the manufactures specs.


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## Da Aardvark (Oct 11, 2012)

^
That sure is a sloppy spec for a subwoofer to have 'that' range of variance in cabinet volume.


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## liquid6 (Feb 15, 2011)

Yep, I agree. Here is the product spec. http://www.kicker.com/CompVR


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## pidaster (Feb 22, 2013)

It's a cheaper, basic sub. Most car audio companies now have an entry level subwoofer with specs almost identical.


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## Phaedrus (Jan 18, 2012)

Da Aardvark said:


> ^
> That sure is a sloppy spec for a subwoofer to have 'that' range of variance in cabinet volume.


Those numbers are for a sealed box. Sealed box specs tend to have some flexibility. The OP has a ported box that was chopped out of a larger home stereo cabinet. The acoustics are going to be...interesting. 

I would suggest a program that calculates the response levels and gain from given driver and box combinations such as "WinISD" -- 
at least that is what I used "back in the day."

Sent from my DROID RAZR MAXX using Woodworking Talk


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