is there any advantage of two subs over one? say we have an amp, you can run a sub off each channel, or bridge it to do one. Is there any advtange over running two besides one for left and one for right sounds? is it worth the extra weight and box. Just wondering couse I have two Rockford Fosgate Punch subs, I've been hanging onto the second incase I ever wanted to put it in, but a mates wanting it.

the sounds from subs being omnidirectional, thre's no need to have left&right ones.

The biggest benefit (for me) is I can use a pair of 10" subs - for the tight response I like, but becasue I have two I also get the punch of a 15".

I run the subs in parallel off of a bridged pair of channels off my amp. Lots of power, tight response, and punch to spare.

i've currently got the one 12" in a ported sub, and when it's turned up it really doofs - i'm not much into the doofy stuff, so generally the amps turned low and it's fine. probably no need for a second one.
to see what happens i'm going to put an 8" in the middle of the car. i've been finding it hard to get the right set up, couse at lower volumes barely hear the sub, so adjust it up a bit, but then there's too much bass at higher volumes. i'll have a bit of a play around.

Seal up the port for a cheap and dirty way of cutting the doof. Should make it tighter.

I originally had it running in a smaller box (about 2/3rds of the size), that was sealed, and the sub made some funny noises, not sure how to explain it, but queer.
so i got the box it came in, cut it in half (as it was two boxes together for the two subs) to make it a single box, and it's running much happier.
but the box is an awkward shape (made for a CRX boot) so I'm gunna have to make my own for the wagon. I'll make it sealed first and if it doesn't sound happy i'll port it.

basicly the more subs u have the bigger boom u gonna get, if ur into rnb or rap 2 subs or more would be awesome, but if ur into punk or metal or whatever u don't really want alot of bass so u would have the one sub

how bout hardcore techno or gabber??

i would probably go 2x10" subs... DOOF DOOF i say!

- If you double cone area with the same power you increase output by 3db
- If you doubble power & keep cone area the same you increase output by 3db

Result is the same although at some point you will no longer be able to keep increasing the power into one sub as it will reach it's limit.

i.e.

1 x 12"sub with 300rms = 100db (for example)
2 x 12"sub with 300rms (150rms each) = 100db

1 x 12"sub with 600rms = 103db (everything else being equal)
2 x 12"sub with 600rms (300rms each) = 103db

Where you get the buggest increase is if you can increase cone area + increase power
2 x 12"sub with 1200rms (600rms each) = 106db

If you have a monoblock generally adding a second sub will produce the greatest increase as you double your cone area (+3db) and lower impedence so power also increases.

With a class a/b you need to consider how you will hook up more than one sub, as in bridged mode most a/b amps will only handle a 4ohm bridged load so adding another sub will have no benefit (apart from driving each sub less hard)

Remember a 3db increase is a doubbling in volume, but it takes a 10db increase in volume for us to percieve it as twice as loud...

Ahh good advice thier pyroay, i personally think one 12' sub hooked up to a decent monoblock amp kicks but over a twin 10' setup ne day but hey thats just me.

I agree, 10's are a little small for my liking

A single 12's sub with 300rms+ is plenty,

If you want more add another one the same...