which is the best ratio

[Joe X]

Basic acoustics of a vehicle are what make it possible to use them and still retain enough low-end response to not absolutely hate the sound of them at stupidly over sized enclosures.

There ya go. You posted my response for me.

Glad Krakin posted here then ...... So we all know about cabin gain...no? Hopefully we all know also that it isn't easy to predict in specific circumstances as well... just saying but more than a few 4th order bandpass threads end up looking very much the same.

[FI 4 life]

Yes I'm talking about all same woofers except 2 18's in 4th order or 3 15's in 4th order.

[TaylorFade]

Have heard up to a 5:1, and plenty other high ratios.

Have yet to hear one that didn't play everything. Leave the paper-theory out of it.

Shrug.

Edit: But everything else, is spot on.

Lol @ "paper theory"

The ratio doesn't dictate the low end extension- because I assume that's what you mean when you say "play everything".

What it can and usually does dictate is the width of the passband of gain. And how retarded of a mountain the FR looks. Plateaus are good, mmmkay?

So with that said... there is no "best" ratio. Only the best compromise

[Triticum Agricolam]

Yes I'm talking about all same woofers except 2 18's in 4th order or 3 15's in 4th order.

Well 18"s aren't the same as 15"s, even though they may be from the same product line.

Two 18"s and three 15"s are going to be roughly the same cone area. The advantage of the three 15"s is you are spreading the power over more voice coils so you are less likely to get power compression. Though with three subs you are going to end up with a different final ohm load than you would with two subs. Depending on your space restriction one of those might be easier to fit than the other.

I can't tell you which will be louder, they will probably be pretty close, but if it were me I'd go with the three 15"s.

[Joe X]

If you get 3 drivers pick D1 ones so you can run at 0.67 ohm.