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low end comparison

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one thing stands in my way of a 12 inch d2. low low end.

i wanted to know how this subs low end compares to a infinity kappa perfect 12.1d

my bro has that sub and as long as i can runble as low and be as loud whil being low as that sub, im content cuase his sub low end lvl is fine for my ears.

stuff to give examples for you to compare on is like the intro to evanesecne song wake me up in side. that a low rumble

or say the huge bassline right befor the drums come in on angels song from sevendust.

i dunno if this would qualify as really low but i know metallicas song the sand mans intro bass drums are the most low hardcore bassdrums ive ever heard. hows a d2 on something like that.

by the way i can not fit a 15.

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if you think that Infinity is low....your definition of the word will be changed after hearing a D2....I can promise you that! After my install, we were amazed at just how low it would get in the car. Nick actually said that it was the lowest he's ever heard the D2 get....try some Telarc Jurrasic Lunch and wait for those stomps....you won't hear 'em, but you'll damn sure feel 'em. Now that's low folks. :)

Josh

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by the way the d2 would be in this box i designed.( sealed)

internal dimensions are 17x18x9 inches. front of box slanted at a 80 degree angle. one square brace, 3-5 inches into the box depth. the walls painted with ED liquid exterminator.

with this i calculated approximently 1.2895058 sqaure feet befor subtracting how much space the driver takes. up. in fact itw uld be nice if someone coul tell me how many sqaur feet thi driver takes up.

so in essence it should wind up around the 1.2-1.4 cubix feet category after i add the polyfill and whatnot.

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cool thx for the reply. i had a few peopl tell me that these D2's didnt drop very well but its not like ive heard many instals and cars that do. hell my brother infinity intal is a chity one. and its plenty low for me. im not after low end but more for accuracy. if get lower than his sub t will be more than enough.

i belive his is like 1.5 cubic feet.

by they way my dads a contractor and he told me mdf sucks. i toldhim about the project and as soon as h heard about bracing the box he was like ok, you need to use better would than mdf. he told my that if i was to use plywood, i tink he said plywood, that it would be much stronger.

so why do people use mdf if this is the case. does it sound better?

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Density is the key in enclosure material. MDF is quite dense and inexpensive. If you are intent on using plywood, I would suggest birch ply for strength and density, but this is rather expensive, around $40 a sheet depending on location. Hence the widespread use of MDF.

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well as long as birch is better i dont care. 40 bucks for a big sheet aint gunna kill me. but if mdf is better ill go mdf

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you wont be getting much of an advantage by going with a birch box though. I dont know why you would want to spend more on something that isn't going to be any better than mdf. any install i've EVER seen used mdf except for snail shell boxes. go with mdf definitely, your dad may be a contractor but I don't know many contractors that specialize in subwoofer box making. listen to the people on here they'll steer you straight.

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ok ill use mdf then. he didnt say mdf is bad he just said that plywood and somehting of that sort would be much stronger than mdf which is very understandable.

but if everyone goes mdf im sure its strong enough for subs.

if i use 3/4 inch mdf should i use 1 brace or 2 braces. the ones im using are those ones that look like big hollow sqaures that touch all 4 sides of the box. i have 9.5 inches of depth in the box with my current designs so im sure i can get 2 in there...

the braces are also 2 inches thick in hight and 1 inch thick in wideness. is that thick enough?

with my newly designed box using 3/4 inch wood i have 1.42 cubic feet with 1 brace and like 1.38 with 2 braces.

could someone please tell me how many cubic feet the 12 inch magnum takes up so i can add that into my calculations. i wanna make sure i got the amount of airspace in the box i want as close to 1.3 cubic feet as i can get. becuase 1.3 cubic feet after displacement is what i was recomended at sounddomain for this driver with 1000 watts rms behind it. does that sound right?

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Magnum 12's displace 0.07 cubic feet. If you end up with less than 1.3 cubes you'll still be fine. Technically all they need is 0.5 cubes to operate at/below a .707 alignment.

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ok so with this new 3/4inch wood design i just posted ill wind up with approximently 1.31 cubic feet of air space once the displacement of all the braces, driver, and 80 degree angle is subtracted from the original airspace of the box.

that sound good? im going for all out sq( hopefully not loosing much low end) pushed by a hifonics brutus bx1000d( that seems to be a popular amp for midrange cost)...

if this box seems good(or very good hehe) to you, would you recomend recomend adding polyfil or fiberglass insulation or whatever. why or why not.

thanks for aLL THIS HELP GUYS!

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...would you recomend recomend adding polyfil or fiberglass insulation or whatever. why or why not.

Yes we recommend using both - fiberglas and polyfil. Why? Because it helps with resonances and aids with effective enclosure volume.

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what is resonance? and can i add just a small amount of polyfill stuff to help with resonance but not add to much to volume. i spent hours geting everything just right to make it 1.31 cubic feet becuase thats what i was told to get to by a knowlegdable person who owns a magnum.

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it appears i have found my mistake in subtracting the angular part of the box. these new confirmed by multiple people internal vulume after displacement is 1.196CF approximently. this now leaves me some room to add that polyfill/fiberglass insulation.

what i changed was how i figured out volume of peice of box being cut off by angle. becuase i was wrong befor

also instead of 2 seperate braces i am now using the same shape brace but im using my 3/4 inch mdf instead of 1 inch. and i will glue 2 of the together so its like 1 brace thats 1.5 inches thick. this way i can use all the same wod for boxes and braces. and it makes it eaier to fit. fitting 2 of them braces would of been a pain and i was told for this small of a box i only need 1.

the orignal wood piece is 17x18x.75. then im cutting out a 15x16 inch box from the 17x18 sheet so it will have 2 inches all the way around left over.. ..that sound good?

i also heard using a round shape in the wood had better effects than a sqaure shape? is this true.

now this just hit me to and i really am not understanding how this works. can anyon help me out. this message came from another forum. by the way the inches hes refering to for internal dimensions are for the depth of the box. since its a wedge the top and bottom pieces of wood are different legths

.

"Hate to tell you this but:

Something is still not right. The thing here is when you have a wedge box the internal dimension cannot be 5.5" and 9.5" when the external dimensions are 7" and 11". It's not possible because of the angles that are needed when the MDF is cut. To get completely accurate dimensions takes some time and thinking. It isn't a big deal and will not make an audible difference, but I just want you to be aware that it is there- for when cutting the MDF.

It is best to draw up the box and fill in #s. Imagine just the top board for the box. Think of how it looks when the angle is cut into it to for the front of the box. You have 2 different lenghts for the board- a top and bottom part(side view of MDF- looking at .75" thickness). Now going further, since that angle is in the MDF think of that angled part. It is not .75" anymore- it's bigger on the angle. You need to get to this # in order to go back and complete the rest of the internal dimensions.

"

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I'm not sure where you're getting this information, but 1.3 cubes isn't a majical number for a Magnum 12. We've had great results in everything from 0.8 cubes to 1.5 cubes sealed. If you box is either 1.3 or 1.2 cubes before polyfil and fiberglas insulation you will be fine. And resonances are peaks or dips in the frequency response caused by a number of things - one of them being lack of enclosure damping. This doesn't really matter in subwoofer enclosures, but it does help make the box seem bigger to the subwoofer.

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is there any way to estimate how many CF bigger your box thinks it is with certain amounts of polyfil. so i can try and guess how big my box thinks it is while im testing out different amounts of polyfil?

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1 lb of polyfil in a 1 cubic foot enclosure makes the subwoofer think it's in 1.25 cubic feet. I would also line the walls with insulation.

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this would again be dealing with mainly resonance, along with increasing what the sub thinks is the box volume.

josh

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how thick should i line it on the walls. 1 inch? 2 inch? and then i just dump the polyfill in the middle?

its not bad for the polyfill or anything to touch the sub is it? or should i like use that metal wire stuff to make it to where the polyfill cant touh it?

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Spray adhesive works well to hold the fiberglas insulation to the walls. Just buy the really small rolls and use that thickness (it's about 2" thick). They're around $6 a roll. It doesn't hurt the driver if polyfil touches it. We have done a LOT of installs where polyfil is almost literally inside the pole piece because the enclosure is stuffed full and it doesn't hurt the speaker. Now if you were to manually shove polyfil up the pole vent, that would cause problems.

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ok last question and i should be done. i was gunna buy edead v3.0 to coat my fiberglass kickpannels in. i was highly recomended to do this so i figured i might as well do it to my sub box? to seal it nice and airtight. putting the liquid edead 3.0 would help sq right?

and buy the way what is the diameter of the magnet on the 12 inch sub. and how many inches into the depth of the sub does the basket end. or at least i think thats what its called. the big metal "basket looking thing" that cases the cone.

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You could use silicone (in the joints) or fiberglass resin (pouring it into the box and rolling it around to coat the inside) to seal the inside of your enclosure. There is no need to purchase liquid deadener.

The mounting depth is 6.75" (just like it states on our web page) and the magnet diameter is 8".

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