multiple driver HT sub ..how to design ?

[JinMTVT]

since i am considering a sub-bass HORN,
i want to also consider the other alternative ...

how could i simulate response of alot of bass drivers?
is there a simple sofware that would allow to see how would behave alot of bass drivers ???

i am maybe thinking about using alot of 18" or 21"
drivers, since i will have the space to do it ..

i am looking for ultimate HT sub bass here,
and since the rest of the system will be line arrays,
a good number of bass drivers could feel at home i believe


how exactly does a few drivers wired together behave?
i think i remember something like +3b for each doubling of the driver numbers ? ( efficiency )

what would be the best configuration ?
i could seal the back and absorb most of the rear wave somehow ...

i will have around 10 cubic meters available for each side
( front size of maximum 9' by 5'width )

thanks for ur time

[planet10]

With that much cabinet volume you have lots of options... a big sealed cabinet (IB) probably makes the most sense. And with 1/ such a big box prone to resonancem and 2/ multiple drivers it only makes sense to push-push them.

what drivers you have in mind?

dave

[Cloth Ears]

Regarding multiple drivers, 3dB is the ideal efficiency increase. And, according to this post, that is true up until efficiencies of around 20% or more. It's a good thread on efficiency and worth a read.

A sub-bass horn is really a waste of space, IMHO (), whereas you'll get better, deeper and probably louder sub-bass using a infinite baffle set-up. A few ideas - William Cowan's IB subwoofer, FAQ for IB Subs and another IB. The only problem is finding the extra room (or basement or attic) to be your enclosure. The more drivers, the better.

[JinMTVT]

hey dave

well i do not have choose any particular driver yet..
as always the 6174 from mcC interests me,
but my wallet doesn't allow for that crazy expense
( at 500$/piece )

probably a good 21" ..could get 10 to 16 of em

the reason why i want to look at simulation
is because i want to see what can be done with a few drivers like that ..
i'd like to be able to reach something interesting at 20hz and sub frequencies ... probably need 130db @ 1m
to be able to get decent output at seating places

still need to work on that room design,
and i'll study the one you have suggested in the past also ..


Infinite baffle ..could always be nice!
anyway you know to get rid of the waves in the ground ?

i don't mind digging 2 big holes in the ground and using some case with wool or something in it ...
though the water level in my land is pretty high..could have some problems ...could probably source some big plastic containers ...
what if one hangs big lumps of wool from the ceiling in the back box ,wouldn't that absorb alot of the waves by making all of the lump moves + heating up the fiber?


what are the difference in the end result at front output from a sealed, infinite, ported ???
i don't think that ported would do it ..since the backwave will be disturbing the output quite much in any config ..

[planet10]

Originally posted by JinMTVT
probably a good 21" ..could get 10 to 16 of em

Some details would make it easier to answer your questions.

dave

[JinMTVT]

what kind of details do you need ??

i am 5' 7", brown hair, athletic body ...
ah nah ..not that kind of details i guess
hahaha


what i want to do, is use the space i have to get the best possible bass and power for my new HT room

so if i need to use 10 or 16 21"inchers, i'lll do it

i was considerin sub-bass horn alot lately, but the problems associated with the delay has me giving it almost up

and i am pretty sure that using alot of drivers will bring distortion to a very low level since they won't have to move that much for the same spl

so what should i do ???

i was thinking of a semi horn within wich a few 21" would be in a central enclosure going push-push together, firing within the horn wich would then point toward the seats ??
i'd have to do a 3d sketch for that ..

[planet10]

Originally posted by JinMTVT
what kind of details do you need ??

pictures, link, T/S?

i was thinking of a semi horn within wich a few 21" would be in a central enclosure going push-push together, firing within the horn wich would then point toward the seats ??
i'd have to do a 3d sketch for that ..

I might already have sketches of that idea.

dave

[JinMTVT]

don't try and steal all my ideas here Dave
hahaha

so what would that give ??
would the horn be somewhat effective or not worth it?
could make it way further in ..

don't look at the pic's quality ..i did that in 5 minutes just to demonstrate ( not at scale either )





this could make a nice semi horn front fired
and would take care of the rear waves pretty good
also would lead to alot of surface for moving air

[JinMTVT]

how important is the volume of the enclosure for push push subwoofers ?
does it matter at all since the waves are cancelling out?

[planet10]

Originally posted by JinMTVT
how important is the volume of the enclosure for push push subwoofers ?
does it matter at all since the waves are cancelling out?

That last statement indicates you have some misunderstanding of how push-push works. The woofers work together not against each other.

If 1 driver requires a volume of A, then n drivers need a volume of nA

dave