making custom speaker box help!

[PuZo]

I am making a portable speaker, basically putting some tweets in a small box, and an amp running off batteries. Now i'm just wondering, should I make a whole at the back of the box, like an opening? I noticed alot of speakers have some sort of opening in the back, do I need to create like a cylinder, and put them inside? Any help would be appreciated. Thanks

 

[swt61]

Quote:

Originally Posted by PuZo /img/forum/go_quote.gif I am making a portable speaker, basically putting some tweets in a small box, and an amp running off batteries. Now i'm just wondering, should I make a whole at the back of the box, like an opening? I noticed alot of speakers have some sort of opening in the back, do I need to create like a cylinder, and put them inside? Any help would be appreciated. Thanks

If you are using tweeters only you won't have any need for a port. Ports are for extending the bass response of a woofer, and if you're not using one...
I think you'd be much better off with a small full range driver personally, as a tweeter isn't going to give you any bass or midbass response at all.

 

[PuZo]

Quote:

Originally Posted by swt61 /img/forum/go_quote.gif If you are using tweeters only you won't have any need for a port. Ports are for extending the bass response of a woofer, and if you're not using one... I think you'd be much better off with a small full range driver personally, as a tweeter isn't going to give you any bass or midbass response at all.

Well its not gonna be a tweeter anymore, its gonna be some computer speakers, but Im thinking of putting the sub facing the ground, exposed(towards the ground) raise it about an inch or 2, and then probably in the front, ill make some holes and put the speakers in there(x2), so then what? Maybe just a whole in the back somewhere? higher or lower? Also anything about cones?

 

[PuZo]

Anyone? There will also be 1 or 2 crossovers in there, so what if it gets really hot inside?

 

[Budgie]

Most speakers put the crossover inside the box. Works fine. Attach it securely so it won't rattle against the box, but you can still remove it later, if needed.

 

[PuZo]

Okay, so what about heat generated? Is it a problem? Should I create a little circular hole at the back?

 

[Budgie]

There will not be a build up of heat in the box. None of the parts in the crossover generate heat. The speaker itself will not generate enough heat to be noticeable unless it is played very very loud for long periods.

 

[PuZo]

Okay, so there isnt a need for a cone? I know on weak subs and really any computer subs, you can feel the air coming out of the hole(cone). Does it make it sound better?

 

[XaNE]

it makes it so it does not sound muffled

 

[PuZo]

Quote:

Originally Posted by XaNE /img/forum/go_quote.gif it makes it so it does not sound muffled

So should I put it in?

 

[Budgie]

The holes are called "ports" and are a certain length and size depending on the box size and woofer specs. They can help extend the bass response and improve woofer behavior, but only if tuned correctly. Tuned improperly, they can make things worse.

 

[Budgie]

PORT Size Calculations and Formulas for WOOFER and Subwoofer BOXES

Check the link- you need all the specs for the woofer and box, enter it into the calculator and it will tell you the port size. It's not a simple "stick a tube in a box" kinda thing.

 

[PuZo]

My sub is only 4 inches, and the highest I can select is 6.5. Would it be easier if I just left it fully closed off? Could I use the same port size and cone from the old sub(I took the sub out of a box that had a port and cone in it) So if the box is roughly the same size, would I be able to use it?

 

[fran]

If you don't mind me saying so - you are going making this thing without any research or basic understanding of how a loudspeaker works. You need to pick a driver and then make the correct size and shape box for it, coupled with the other items needed like a crossover network, damping, and a port.

They way you're going your taking a shot completely in the dark hoping to hit a bird 200yds away.

FWIW, you should take a look at some of speaker design sites and make one of those. Zaph|Audio is a good place to start - that way you won't be wasting money on the drivers etc and getting crap sounds.

Its not that hard to make the box etc, but to design from scratch is another matter.

Fran

 

[PuZo]

Like I said before, this isnt going to be extremely loud, its just a small maybe 2 feet, by 2 feet, by 2 feet box, that has a small battery powered amp inside. I just want to know if the cone from the box it came from, will work in roughly the same sized box?