Hello good people,
While waiting for stains and paints to cure on my Rythmik subs for the main-floor HT, I thought I'd ask a few questions about an IB setup in the basement HT.
First off, I bought two SI DS4 18s while on closeout, so these are the drivers I'm working with for the time-being..
I'll be driving them with a Behringer iNuke 6000 DSP also.
I want to put them in a manifold that couples it to the basement ceiling, up through the floor of another 10'x18' room on the main floor.
Here's the thing: There's not enough room between the wall and first joist due to space limitation (wall measures 8" out from foundation/boundry joist).
There's also not enough room between first and second joist due to it getting in the way of the projection screen.
So, as long as I build the manifold large enough to comply with the SD of the drivers, is there a reason I couldn't place it ,basically, straddling the joist between the 1st and 2nd areas?
Any further clarification gladly provided...
Thanks in advance
-Steve
While waiting for stains and paints to cure on my Rythmik subs for the main-floor HT, I thought I'd ask a few questions about an IB setup in the basement HT.
First off, I bought two SI DS4 18s while on closeout, so these are the drivers I'm working with for the time-being..
I'll be driving them with a Behringer iNuke 6000 DSP also.I want to put them in a manifold that couples it to the basement ceiling, up through the floor of another 10'x18' room on the main floor.
Here's the thing: There's not enough room between the wall and first joist due to space limitation (wall measures 8" out from foundation/boundry joist).
There's also not enough room between first and second joist due to it getting in the way of the projection screen.
So, as long as I build the manifold large enough to comply with the SD of the drivers, is there a reason I couldn't place it ,basically, straddling the joist between the 1st and 2nd areas?
Any further clarification gladly provided...
Thanks in advance
-Steve
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Just to add:
1. I have determined that this spot is not in a null by reversing the listening position and a sub.
2. This manifold will be large enough to add two to six more 18s in the future if SPL is inadequate.
3. The joist that I cannot remove will not be physically blocking or restricting the drivers in any way.
(unless someone thinks they will, or if another problem is foreseen, which is why I started thread)
Also, see attachment for the driver specs: Not listed is power handling, which is listed as 1200wrms.
1. I have determined that this spot is not in a null by reversing the listening position and a sub.
2. This manifold will be large enough to add two to six more 18s in the future if SPL is inadequate.
3. The joist that I cannot remove will not be physically blocking or restricting the drivers in any way.
(unless someone thinks they will, or if another problem is foreseen, which is why I started thread
)Also, see attachment for the driver specs: Not listed is power handling, which is listed as 1200wrms.
Attachments
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I.B.
Greetings,
If I am following your thought process correctly, you should be just fine,
The basement is the actual Home Theatre room, and the room directly upstairs of it, acts as the enclosure ? As long as here is an air tight seal, and you provide enough unrestricted air flow (always grand total SD+ ) Deep bass does not care. Congratulations, on doing bass the best way possible. You have an effective enclosure of 1440 cubic feet, assuming an eight foot ceiling in the room above.
Greetings,
If I am following your thought process correctly, you should be just fine,
The basement is the actual Home Theatre room, and the room directly upstairs of it, acts as the enclosure ? As long as here is an air tight seal, and you provide enough unrestricted air flow (always grand total SD+ ) Deep bass does not care. Congratulations, on doing bass the best way possible. You have an effective enclosure of 1440 cubic feet, assuming an eight foot ceiling in the room above.
Attachments
Hey thanks Scott, I really appreciate it.
You are correct on all points.
And thanks for the photo. Imagine that the board between the 2 sets of drivers in that pic is 2" wide and 8" deep, that's what I was describing.
Glad to help. And, just to clarify, the plenum dimensions are
17.25 inches x 64 inches, which yields 1104 square inches
The 8x 15" drivers posses an SD of 1064 square inches.
One bit of caution about having I.B. bass: The amount of visitors to your home will increase exponentially
About this, why does it say over at ibsubwoofers that (2) 18's are able to use a manifold opening which is 18"x12"?
About this, why does it say over at ibsubwoofers that (2) 18's are able to use a manifold opening which is 18"x12"?
Here's what it says:
15) How big an opening should there be for my manifold ?
{{When I built mine, I went with the "theory", however, I also use push-pull, slot load mid-bass, where the manifold opening is 1/2 that of SD and it still yields excellent results}}
In theory the best choice for a manifold would be an opening equal to the summed swept volume of the diameters of the drivers being used. In the real-world an opening this large isn't practical nor is it necessary. The recommendation is make the opening as large as practical given the limits of stud/joist spacing or other physical considerations of the install. That said.....
As a basis for determining a practical outlet size we can reference Collo's gap calculations for the distance between the driver and the bottom plate of a sono-sub. Below is the quick reference guide as seen on Collo's website.
As an example we see a pair of high excursion 18"s would have a recommended opening 18" dia X 12" wide. With an IB the height of the opening is often larger than the diameter of the driver, and the width is usually that of a stud-bay or the joist spacing. So we're within the recommendations seen in the graphic
Invariably someone asks "how small can the opening be?" It's best to avoid having an opening smaller than 50% of that from the calculations.
IB subwoofer FAQ page
Many thanks Scott, really appreciate it.
I'm still rather new to all of this, so that clears things up quite a bit.
Next up, laminating OSB/baltic birch, with bracing, for a minimal flex manifold.
I should be fine with two 18's of SI's caliber, but expansion to 4 is always in the cards I suppose..
I like your comment about having much more company once an IB is in the house..
I'm still rather new to all of this, so that clears things up quite a bit.
Next up, laminating OSB/baltic birch, with bracing, for a minimal flex manifold.
I should be fine with two 18's of SI's caliber, but expansion to 4 is always in the cards I suppose..
I like your comment about having much more company once an IB is in the house..
Yeah, I use to have an Altec tech bulletin [many were W.E. in origin] discussing optimal driver loading with 2:1 being considered the optimum, so have used it on all manner of horns, other BP, TL designs with excellent results. FWIW, back when DIYers got interested in the B0z3 WC, I noticed that a 2:1 Sd/pipe area was recommended in the patent.
GM
Hi GM, I know that W.E. is Western Electric, but what is "B0z3 WC"? A T-line? Thanks.
Looks like the inner dimensions of my manifold will have to be larger than first expected in order to allow the addition of 2 more 18's in the future, whether I like it or not.
I'll draw up a plan later, then scan and post, it certainly can't hurt for future IB builders searching old threads.
Looks like the inner dimensions of my manifold will have to be larger than first expected in order to allow the addition of 2 more 18's in the future, whether I like it or not.
I'll draw up a plan later, then scan and post, it certainly can't hurt for future IB builders searching old threads.
OK, after having a bit of fun at Dr Amar's expense (RIP), back to the project at hand.
I did a couple rough sketches of proposed design, these two are what I came up with first, but I think I might as well place the drivers that are in the box on the same plane as the (optional) ones that will be outside the box in reverse phase.
Anyone have thoughts? Thanks.
I did a couple rough sketches of proposed design, these two are what I came up with first, but I think I might as well place the drivers that are in the box on the same plane as the (optional) ones that will be outside the box in reverse phase.
Anyone have thoughts? Thanks.
Attachments
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Attachments
Thanks Scott, Interesting indeed!
I was chatting with Thomas over at the IB site, and he stated that the opening I proposed would work out fine, but thought that I should have all drivers outside the box, firing into the manifold for some reason..
Do you happen to know why this would be preferable?
Anyway, I think I'm going to build this thing utilizing 2 drivers at first, just for starters.
My reasoning behind this being the raw specs on these beasts, with 1200wrms power handling and over 2" of throw peak to peak, I think I might be OK.
(then again, I don't know, given what folks say about clean bass and what it makes them want to do...and that's "turn them up!"
Any thoughts on this appreciated..
I was chatting with Thomas over at the IB site, and he stated that the opening I proposed would work out fine, but thought that I should have all drivers outside the box, firing into the manifold for some reason..
Do you happen to know why this would be preferable?
Anyway, I think I'm going to build this thing utilizing 2 drivers at first, just for starters.
My reasoning behind this being the raw specs on these beasts, with 1200wrms power handling and over 2" of throw peak to peak, I think I might be OK.
(then again, I don't know, given what folks say about clean bass and what it makes them want to do...and that's "turn them up!"
Any thoughts on this appreciated..
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