i have 6,5 inch and 5.25 inch speakers and i am wondering if i need to put them in boxes or not. if i do need to does the size of the box matter? or the dimensions?

what is the difference between 4,5, or 6 inch speakers? if i add more which size should i add?

 

what speakers are you thing of ?
focal speakers like about 30L = your door sealed is about 30L
and your X2+ 1= 0 is x not -1 ?

 

one thing to remember is that they like box's - so if your door is your "box" as zzzzz said above.. try to seal up your door as best you can (don't go crazy overboard) but if you take your door panel off and there is more holes than metal, try to seal some of that up so it's more like a box and less like a cheese grater

 

i have 6.5 and 5.25 inch speakers and im wondering if i can just mount them in a door or i also have a headliner with little compartments im wondering if i should build little mdf enclosures in the doors and headliner or if i should just mount them in there and sound deaden it.

and no the answer is not -1 because you are squaring "X" and neg times neg is a positive. therefore is X=-1 then the equation is equal to 2 not 0

 

Am I mising something? Where is this equation?

 

you can use foam baffle inserts , but if you have the time to build boxs that is the best way

 

so ill build boxes for them but what is the difference between a 5.25 speaker and a 6.5 speaker? if i add more speakers which size should i add?

 

Off topic but does x = i ?

 

the different between sizes of speakers is generally the surface area of the cone, and when the s.a is bigger then the power handling is usually higher as well. so it's depending on what sound you want. more surface area = lower frequencies and small surface area = higher frequencies. i recommend 6.5" speakers unless youre planning on using them for just tweeters.