Box Building Process. (Pics)

[CBFryman2 5,000+ posts]

A too large of a sealed box has two effects, both of which are kinda related since the first is only for certain drivers:
1. The sub begins behaving as though it is in what is called an infinite baffle. I won't go into the specifics, but the subwoofer is essentially open with no enclosure on any one side.

2. The sub will bottom out because it's not made for IB applications, thus resulting in mechanical failure.

Basically, it has too much air and the sub cannot rely on the sealed environment to "control" the cone like it needs to.

If none of the above happens, it'll just sound boomy and like ***. Otherwise, I like your drive, keep it up. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

BUt, in that enclosure Qtc is only ~0.8 with thoes subs... perfect for SQ

 

[PV Audio 5,000+ posts]

BUt, in that enclosure Qtc is only ~0.8 with thoes subs... perfect for SQ

I know that, I read the specs. He asked in general, so I thought I'd see if I could help 'im out. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[sc197 10+ year member]

What's qtc mean? I'm clueless.

 

[supraman1379 10+ year member]

This is what I don't understand. The whole box together is 4.7cf which only 1 CVR reccomends 4.6cf in a sealed box. So if I put just 1 of my CVR's in that box then yeah it'd be a mess since the box would be too big. But if I put 2 in that box with each sub seeing only 2.35cf then I don't see the problem. The first 2 pics are before I cut the box back some so it's not really that big now. It's half of what the book/manual reccomends. As for powering them, I'm actually "underpowering" them. I know the bigger box says 4.6cf is good for 300wrms but I'm not using 4.6, I'm only using 2.35. I don't really see a problem there, but like I said I'm new at this and I probably sound like a dumbass trying to explain this. Haha but we all start some where. I guess the person who sent me the box plans didn't know what he was doing or he wanted to see my stuff get messed up.

Ok. Listen. I have gone through enough of these subs to know what Im talking bout.

Just keep your gains down. I built one box at 1.25 cubes. And 400 rms was too much for the sub.

So trust me, keep your gains down.

 

[PV Audio 5,000+ posts]

What's qtc mean? I'm clueless.

It's the total Q of the woofer and the box. IIRC, it accounts for all losses as well.

 

[sc197 10+ year member]

Since everyone is saying that box is too big, what should I make the volume then to get deeper bass/better sq than my old box?

 

[squeak12 10+ year member]

Just put something in the box that will take up some space such as 2x4 screwed down etc.

 

[CBFryman2 5,000+ posts]

Or leave it the way it is, YGPM SC197. i think i answeared any questions you may have had about Qtc.

if you need any more help i'm going to be gone for a week, PM me if you want and ill repy when i get back. if that is too long post up in here or PM some of the more prominent members. im sure someone will help you, or go over to the site i told you about because they will take care of you in a thread

 

[Fast1one 10+ year member]

Dont worry about it bro, that box is fine. Just watch your gains on your amp and your subs wiill be fine //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[helotaxi 5,000+ posts]

As long as you don't play the role of loose nut behind the volume knob you'll be fine.

What they have been tryin to tell you is that there are two types of power handling, because there are two ways to damage a sub. The first is thermal power handling. This is entirely related to how much heat the sub's voicecoil can get rid of. This is the power handling that you see published because it is largely independant of enclosure. The second type is mechanical or displacement limited power handling. This is entirely dependant on the enclosure. Since you can blow a sub by exceeding its mechanical limits, you have to consider how much the sub moves with the power it is given. This is dictated by the damping provided by both the sub itself and enclosure and in most cases is less than the thermal power handling, especially in a selaed box. In a sealed box, the percentage of compression of the air inside the box determines the damping. The higher the ratio of the swept volume of the sub (surface area of the sub times excursion) to the total volume of the box, the more force the enclosure exerts on the cone of the sub and thus the more power you can run to it without reaching the limits of its suspension travel. In most cases the mechanical power handling is a guessing game (you can computer model the sub and enclosure to get a pretty good idea but it still isn't exact), but for you Kicker has taken the guess work out of it and tells you what the mech powerhandling is for the recommended enclosures.

 

[NeverEnuffBass 10+ year member]

Those subs are awsome I had four of them before I switched to 15's. Only problem I had was they didn't seem to like the boxes i made for them.

 

[supraman1379 10+ year member]

This is my first time building a sub enclosure so sorry if it doesn't look right or I used the wrong stuff to put it together. The box is for two 12" Kicker CVR's, the box is 4.7cf. With the divider each sub will get 2.35cf of volume. The deminsions are 32"w x 14"h x 23"d. The reccomended volume for the CVR's are 4.6cf. Sorry that it isn't finished yet, but I thought I'd share the pictures to see if I'm doing everything smoothly. I'll update with more pics once it's done if anyone cares.

Old Radio Shack prefab box sitting beside the new box. (New box not glued yet so that's why you see the large gap on top)

Shows how bigger it is compared to my old.

The sides and divider finally glued together along with the box terminal.

Next step is to cut the holes for the subs, re-silicone the cracks again to make sure there's no air leaks, and finally get the carpet put on and see how much of an improvement it is from my old one.

Any tips or advice? Hell I'll even take negative feedback. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

I went over your measurements and youre definately a lil big.

What would you think about these dimensions? All I did was change the depth.

32L x 14H x 15D

My measurements with those dimensions I listed came out to about 3.88 cubic feet.

Everyone that reads this tell me what you think of those dimensions.