a few questions on car audio. please help

[Dj Dfa]

Hey everyone! I'm new at this website and at audio. So if my questions seem somewhat stupid...well please stick with me and help me out!

Here goes...
First question, where can i find out what size box to make for a particular sub? even if i dont know the t/s parameters for the sub. would it be possible just to build a box to hold the sub and it would work? Also, if i wanted to port the box, and tune it to a certain frequency how do i find out what size the port should be and what size the box should be? What if i want the frequency to be 30hz or what if i want it to be 50hz...that kinda thing.

my next question....
I have a prestige amp that i got as a present, im not sure but it might be a 400 watt amp. its a single channel. When it was hooked up in my car, by a professional, it was wired to an Eclipse 10 in sub. with a nom imp. of 4 ohms. So i know the amp can handle the 4 ohms....How do i know if i wire it into something with 2 ohms, that i wont overheat the amp...I was also given two rockford fosgate 10 in subs. (4 ohms each)When i wired them parallel into the amp, it killed my car battery really quick. Is that because i was drawing too much current from the battery? What if i wire the two rock fos subs in series, that'd be a Req of 2 ohms...would i overheat the amp? Would that save the car battery? When the car was hooked up to the single 4 ohm it didnt kill the battery.

my last question is quick...
how do you wire two subs out of phase so they "push/pull". is that wired in series/parallel/or something else?

oh and my last question...
if you wire two subs in series, is the second sub supposed to recieve less power than the first? or did i just do a crappy wiring job? hehehe if ANYONE could help I would really appreciate it...also if anyone knows about this stuff or just wants to talk to me, you can IM on AIM at DjDfa (please do! even just to chat!)

Thanks, Max

 

[thylantyr]

This is my favorite place to talk about car audio.
http://www.caraudioforum.com/vbb2/

 

[AudioFreak]

Here goes...
First question, where can i find out what size box to make for a particular sub? even if i dont know the t/s parameters for the sub. would it be possible just to build a box to hold the sub and it would work? Also, if i wanted to port the box, and tune it to a certain frequency how do i find out what size the port should be and what size the box should be? What if i want the frequency to be 30hz or what if i want it to be 50hz...that kinda thing.

Can you tell us what type of sub you have?

What if i wire the two rock fos subs in series, that'd be a Req of 2 ohms

Would be 8 ohms not 2 ohms

my last question is quick...
how do you wire two subs out of phase so they "push/pull". is that wired in series/parallel/or something else?

Either. Phase is determined by reversing the +ve and -ve leads on 1 of the drivers.

oh and my last question...
if you wire two subs in series, is the second sub supposed to recieve less power than the first? or did i just do a crappy wiring job?

If both subs are the same, they should receive the same amount of power.

 

[BabaBooey]

I wouldn't recommend wiring one sub out of phase with the other unless you're going with an isobarik setup. It's a recipe for cancellation.