How important is 10x vas?

[jakethessnake]

I'm not sure which way I want to go yet, or what is more important. Either way I'm sure I'll be happy as the room is only 12x14, but I'd just as well get the most I can out of the setup. The crawl space the subs will be mounted in is around 281 cubic ft. If my math is correct, these are my options. I know 4x vas is acceptable but would it be better to have more cone area/displacement rather than 10x vas? This would be a manifold setup, stacked two high for the 4 subs.

2 18" IB Fi subs =roughly 10x vas
4 18" IB Fi subs =roughly 5x vas
4 15" IB Fi subs = roughly 11x vas

I'm not so sure I would even want to do 4 18's as it would probably be overkill and the manifold would be a little taller than I'd like. The subs will be powered by behringer ep2500. The four 15's have more cone area than the 18's, but the 18's displace slightly more. Also, using only two subs the amp would only be at 50% capacity unless I overpowered them (not sure how big of a deal this is in IB applications, I've been doing it in car stereo installs for years in ported boxes). So would 4 15's at around 500watts a piece be better than 2 18's at around 500watts a piece? Too many options going this way, but the end result will be worth it

[wingman]

Read FAQ there you have your answer.

5xvas faster roll of, but more drivers = higher sensitivity and dynamik.
10xvas better roll of with out eq.

you can always use eq to flatted your response .

I would use 4 18" and eq

[ThomasW]

There's little need for 4-18"s in a room that size. 2-18"s or 4-15"s would be more than adequate.

[jakethessnake]

That's kind of what I figured, even though I'm used to being pretty loud (140 db's in a car). 4 15's would fit better and still be more than enough.

[jman]

The difference between 5x and 10x VAS is minor compared to the massive difference between a typical box sub and even just 5x.

1 cubic' = 28 liters
18" cube = 94 liters

281 cubic' = 7868 liters

You could start with 2 drivers but make the manifold with 4 cutouts and just seal 2 of them. If 2 18's isn't enough you can easily add 2 more.

[Nathan]

I have a 120ft^3 room for the back of an IB I am planning. I will use Fi IB drivers, so here are my options:

2 - IB318 = 4.4X Vas
2 - IB315 = 6.23X Vas

My listening room is ~ 15'x22' with 2 ~8ft openings into a larger room and the IB will be installed behind and to the left of the projector screen and front main speakers. I have a Dayton ported box sub now, so I am sure either would be a significant improvement, but would I be better off with lower Vas multiple but bigger drivers or smaller drivers but higher Vas multiple? If possible I would like to avoid an EQ to begin with. Thanks.

[ThomasW]

This will be short since I typing with only one hand.

Go with the 18's, use an EP-1500/2000.

I've never heard a sub that didn't benefit from the judicious of EQ.

[jakethessnake]

I've changed my mind again . I'm moving to a house with a full basement so I will have a lot more room . Somewhere around 700+ cu ft of airspace. And I think I've decided on 4 of the AE-IB15's, they seem to be a pretty good deal for the $$. I've already got the ep2500 and the DSP-1124P (I think that's the one ?). Just waiting on getting settled in the new house and finishing the basement, that will probably take a year or so

[chadcummings]

Ok, along the same lines but a little different.

The guy finishing my basement made a room next to my theater larger than I wanted to...thanks to the Mrs input while I was away.

That means I now have to sacrifice in both my theater space and IB space.

The maximum IB I can create is not at 6375l which puts me at 3.4x Vas for my DPL15's.

I know I can fill a lot of the space with insulation to help it think it is a bigger space.

Will it be enough or will my IB suffer too much.

I had originally wanted 8x DPL15's which I currently own.

Should I reduce the number in half. I was hoping to use the 8 to have an increased sensitivity.

thanks

[ThomasW]

Certainly can't cram 8 drivers in that small a space.

Watts are cheap these days, I fail to see the reason to double the number of drivers simply to increase the sensitivity.

[chadcummings]

I have a face 1200 amp to drive them so I have plenty of power.

So your recommendation would be to run with 4 and sell the other 4.

That would give me 6.8x Vas.

[ThomasW]

Let's go back and start using your original build thread.

Also would you post an updated drawing showing what we're no working with as far is the IB space is concerned.

You can find you old thread by clicking your user name..