2x18" Ficar IB3 Infinite Baffle sub - AVS Forum
DIY Speakers and Subs > 2x18" Ficar IB3 Infinite Baffle sub
Starkiller4299's Avatar Starkiller4299 02:19 PM 11-29-2010

Some of you may have seen my thread at the Cult of the Infinitely Baffled; this thread is for everybody else without an account .

About a month ago, things kicked into gear--I was told I needed some surgery on my shoulder, and that I would be able to use my arm for 2-3 months. So completing a sub was now or never!

Why IB? Well, truth be told I was originally thinking about a couple of LLT sonotubes with Elemental Designs 18" woofers, and then about a large horn-loaded enclosure. Both of these design types offer superior efficiency and can reach into the infrasonics, but I had always wanted to go as low as possible. Then I heard a remark from a respected forum member that he had "never heard a bad IB", and that got me thinking. With the new advent of purchasing a house, IB was possible, and for me, seemed to hit all the right criteria.

And without further ado, pictures! I apologize for the mediocre picture quality in advance.

Here's a pic of the living room, pre-installation. The hole was proposed to be in the front-right corner; SPL testing confirmed this as a reasonable location.


Since I had too much free time, I modeled the manifold in Sketchup. I was a good learning experience, if nothing else.


Scaaaary (and sauna-like) Attic:


Here's the frame installed on the joists:

 



Ceiling Cat has nothing on me!


Picture of a driver; note the protein container dwarfed behind it.


Manifold, pre-installation:


Manifold, installed:


Side Shot:


The manifold is made of 2 layers of 3/4" ply. It's plenty sturdy and quite a bit lighter than MDF would be. I was able to put together a circle jig for my router for under $5 with a 1/4" piece of lauan (sp?) ply and a few machine screws. Once I found the right set-point to drill through, the circle cutting was surprisingly easy. I made some simple driver clamps from a stock 1/8"x1" bar of aluminum; cutting it down to small pieces, drilling a hole, and grinding down the rough edges took no more than a couple hours, but was well worth the time once my buddy and I were up in the attic, installing them!

Looking up into the manifold:


I plan on buying or building a vent cover to conceal the hole with, but that's a little ways off right now.

My impressions? Sheer awesome. This thing hits hard with no boom associated with it, to a level far louder than I'm comfortable with for more than the occasional demo, anyways . I have yet to really plumb the depths of its capabilities; the rest of the system (Paradigm Monitor 5's and Recession Buster surrounds) just can't keep up with it. I found a kind soul who sent me some demo discs, and it champs the more notorious "Bass" scenes (ie, Flight of the Pheonix, Black Hawk Down, etc), at least at the levels I've been brave enough to attempt. I need to bring in a dedicated power line to the EP4000; it's making the lights dim when I crank it, and I think lowering the voltage om the line enough to cause the receiver to shut off o_O. Fortunately, I have a roll of 12ga laying around .

If anyone has any questions, I'll do my best to answer them. If you have the opportunity, I'd highly recommend checking an IB setup out--it's just loads of fun .



dykz34's Avatar dykz34 03:22 PM 11-29-2010
Sweet build, I'm jealous! Thanks for documenting!
gperkins1973's Avatar gperkins1973 03:37 PM 11-29-2010
That's one scary attic mate. What's the volume off the attic and have you measured the spl readings at 10hz yet to see how it is.

Great work though.

Very jealous.

cheers

Graham
kryptonitewhite's Avatar kryptonitewhite 04:45 PM 11-29-2010
kickass!~
DougSmith's Avatar DougSmith 04:48 PM 11-29-2010
I've been thinking about doing one of these - either just like yours, or with 4 AE IB15s (except mine would be in the floor). Have you tried taking any measurements?
soundemon's Avatar soundemon 05:38 PM 11-29-2010
I'm setting up to run a false wall IB, and have been debating 2 drivers for 8x VAS or 4 drivers for 4xVAS.
only thing I'm worried about with 2 is running out of excursion at high volume levels. Sounds like you are listening pretty loud (sorry for the pun) can you comment any further on the volume levels you're listening at, and how hard you can push the 2?
Mach5 IXL 18's are what I'll be using
FOH's Avatar FOH 06:54 PM 11-29-2010
Quote:
Originally Posted by soundemon View Post
I'm setting up to run a false wall IB, and have been debating 2 drivers for 8x VAS or 4 drivers for 4xVAS.
only thing I'm worried about with 2 is running out of excursion at high volume levels. Sounds like you are listening pretty loud (sorry for the pun) can you comment any further on the volume levels you're listening at, and how hard you can push the 2?
Mach5 IXL 18's are what I'll be using
I wouldn't let a 4x or 8x comparison decision determine driver quantity. I'd examine your space, cubes, materials etc., and listening playback level habits, and allow that aspect determine the driver lineup.

The 10x guideline is certainly optimum, however it truly not necessary.

Also, if you're going to pursue a direct radiating line array, wall stiffening is paramount. Do not underestimate the importance of wall rigidity in this scenario.

Good luck
Starkiller4299's Avatar Starkiller4299 08:01 PM 11-29-2010
I'm glad you like it .

gperkins--I guesstimated the volume at 5400cu ft by taking 1/2 base*height, then multiplying by the length.

I don't have any measurements yet; I need to hunt down some measuring equipment first. The 'preliminary' SPL measurements were performed with a SPL app on my Droid phone--accuracy not guaranteed.. EQ will then shortly follow.

Doug--word on the street is that AE is having supplier issues. Seems like Fi may be your best bet. But yeah, I was pondering over that decision myself. Overall, though, the IB3's offer the best displacement, L/$.

Soundemon--the general rule of thumb is that if you must decide between more drivers or higher VAS ratio, pick more drivers. Limited space is somewhat mitigated by using sound absorbers, like fiberglass insulation, to absorb the backwave. FOH is a solid source of information.
Starkiller4299's Avatar Starkiller4299 04:54 PM 12-31-2010
Turns out my IB is quite good at exciting the resonant frequencies in my living room. I just isolated one of these to the hollow door of my front closet. Any ideas on how to dampen this out (in the most cost effective manner)?

So far, I have:
1. Add weather stripping to the frame to damp out vibrations
2. drill hole at top and fill with expanding foam (a la Great Stuff)
3. Replace the door panel with a solid door (very $$$)

Funny that the weakest link right now is the amp--I got some clipping lights last night demoing at -4 on the receiver, 17 on the amp. I think it just can't pull enough from the 120V circuit it's on. These woofers are beasts!
kryptonitewhite's Avatar kryptonitewhite 07:06 PM 12-31-2010
Im a huge fan of Great Stuff. Hows the voltage drop/receiver shut down situation been doing? I clip when I push hard as well as shut down myself...wish all I needed to do was run some more wire but everyone tells me not to even think about upgrading my electrical myself
Thomas-W's Avatar Thomas-W 09:41 PM 12-31-2010
Quote:
Originally Posted by Starkiller4299 View Post

Turns out my IB is quite good at exciting the resonant frequencies in my living room. I just isolated one of these to the hollow door of my front closet. Any ideas on how to dampen this out (in the most cost effective manner)?

So far, I have:
1. Add weather stripping to the frame to damp out vibrations

Best low cost option
Quote:


2. drill hole at top and fill with expanding foam (a la Great Stuff)

That will blow the door apart
Quote:


3. Replace the door panel with a solid door (very $$$)

Look a the borg or Lowe's, they aren't that much, but they still may rattle in the jam
Starkiller4299's Avatar Starkiller4299 08:23 AM 01-01-2011
Quote:
Originally Posted by Thomas-W View Post

That will blow the door apart

o_O Guess I better avoid that then. I'll give weatherstripping a try.

I haven't had any further issues with the receiver dropping out. But then again, I haven't been above '0' on the volume, either. So no real surprise there .

For more wires, I plan on going halfway myself. Cut out the hole for the socket, run the wire, connect the wire to the socket--you get the idea. And leave the part where it gets hooked up to the breaker box to the pros. A trained monkey can run cable--not too difficult. So why pay a trained electrician to do it?
mcsoul's Avatar mcsoul 10:15 AM 01-01-2011
Does the manifold act like a port in this configuration and if so, what would be it's properties (bandpass)?
Thomas-W's Avatar Thomas-W 11:26 AM 01-01-2011
Quote:
Originally Posted by mcsoul View Post

Does the manifold act like a port in this configuration

Port? Nope.

Properly sized the output from the drivers combine so it functions like a single large compression driver.

Quote:


what would be it's properties (bandpass)

If the manifold opening is way too small it can manifest bandpass characteristics. One can see that effect using a box design program like Unibox or WinISD Pro.
FOH's Avatar FOH 11:29 AM 01-01-2011
Quote:
Originally Posted by Starkiller4299 View Post

o_O Guess I better avoid that then. I'll give weatherstripping a try.

I haven't had any further issues with the receiver dropping out. But then again, I haven't been above '0' on the volume, either. So no real surprise there .

For more wires, I plan on going halfway myself. Cut out the hole for the socket, run the wire, connect the wire to the socket--you get the idea. And leave the part where it gets hooked up to the breaker box to the pros. A trained monkey can run cable--not too difficult. So why pay a trained electrician to do it?

Actually, assessing the circuits, and dedicating the appropriate existing receptacles being used would be the first step. That's a much more prudent approach than cutting in new locations and running new wire. For high amperage, HT amplifier duty, it's essential that connections are very tight, and mechanically sound at each point. Connections are far and above the most common point at which failures occur. To say a trained monkey can do everything except make the connection at the panel, is an oversimplification. There are many tricks and techniques that one discovers after decades around the electrical industry, that no book or internet instruction could ever approach.

Even though it's simple residential wiring, and not an industrial application, the key is that it's a dwelling unit. Which by definition means individuals sleep there, that turns it into an entirely different ballgame with regard to safety.
Starkiller4299's Avatar Starkiller4299 11:54 AM 01-01-2011
Fair argument, FOH, but I want a different receptacle, and since I need additional current carrying capacity, I'm pretty sure there's a need for some more wire. The existing 14ga just isn't going to carry 20 amps .

Very good point about the connections though. One of the things I'd have the electrician look over and give his OK on before he left.

And just for clarity, I'm not completely pulling this outta my rear end. A coworker of mine used to work as an electrician before he hopped the fence to engineering, and he suggested I do those parts myself. Of course, he knows that I'll do all the appropriate research before I go drilling holes in my walls, so maybe that's a factor too .
Starkiller4299's Avatar Starkiller4299 05:55 PM 01-11-2011
Following up on the weather stripping: works very well in damping out vibrations. Just don't go and run the tape all the way up and down the door--you'll never be able to exert enough strength to compress the foam! Instead, do the top and bottom foot of the door.
Starkiller4299's Avatar Starkiller4299 02:55 PM 02-19-2011
Proof is in the pudding:



Blue is before EQ, purple is after. Measurements were taken with a Class 1 SPL meter , calibrated flat from 20-20kHz, with .7db accuracy--borrowed from a friend. I understand now why REW is so awesome--sure would have loved to use it after my 10th time taking 1/6th octave tones and plugging them into excel in the other room . Let's see...$400 for a laptop, $99 for an external sound card, $70 for a mic....Damn you, cold reality!

Clearly still not perfect, but OMFG the bass is better. The boominess I was noticing at around 100Hz is completely quashed, and I didn't know what I was missing at 40Hz. And I'm just using 2 filters! I may try getting a little fancier with it (ie, try a hard knee I've heard so much about) but I'm pretty happy with it now .
LL
Starkiller4299's Avatar Starkiller4299 08:37 AM 02-20-2011
Oops, looks like the image was deleted from the last post . Edited to include it again.
gperkins1973's Avatar gperkins1973 10:00 AM 02-20-2011
How comes it is dropping off at 10hz. Aren't IB subs meant to be a large sealed sub and go much lower than 10hz and have a roll off like a sealed sub. That graph looks like it has a hpf.
Starkiller4299's Avatar Starkiller4299 11:04 AM 02-20-2011
It well might--that meter was only calibrated to 20 Hz, so anything below that isn't 100% reliable. Also, note that the 11Hz and 12.5 Hz are at the normal SPL range, so it's very possible there's a room node at 10 Hz. The fact that it looks like it's trending so hard down may be contributed to Excel's line-smoothing, as well. I wonder how 8 and 9 hz fare?...
gperkins1973's Avatar gperkins1973 11:06 AM 02-20-2011
Or even 5hz!
Starkiller4299's Avatar Starkiller4299 11:43 AM 02-20-2011
Just for you, gperkins--the battery power ran out at 6 Hz, but I think it'll give you a decent idea of what's going on...



Now that I think about it, I should compare it to what's expected, per Winisd:



So really, not too far off. A bit wild under 20 Hz, but that's fine. I personally couldn't hear much anything under 20Hz, mostly just some faint driver noise from the excursion, so I'm really not gonna worry about how flat the curve is that far down. Plus, I don't want to give up precious excursion, and down there, it's pretty greedy.
LL
LL
jamesbos's Avatar jamesbos 02:57 AM 09-28-2012
I built underfloor loaded speakers to go with my bailey transmission lines and IB boxes, awesome bass. But had to switch off as the neighbours were involved living in a semi, their plates were moving on their shelves. You could feel it thro' your feet really lifelike. So if you live in a detached house go for it.eek.gif
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