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Discussion Starter #23 (Edited)
Alright Guys, my recent IB build is pretty much complete! :D

4 FI IB3-18s
Behringer EP4000 amp
BFD1124p
Multieq XT32






I installed some Sound reactive LEDs in the vents, for music and display, its fun.
Sorry about the mess....work in progress....

Without flash:




With Flash:




First measured room response, Multeq XT32 only:
Still tweaking tho :nerd:


:hsd:

Here is a short review I posted on another forum:

These things are monsters and have literally scared the breath out of me quite a few times so far... Incredibly dynamic, Sound quality is insane... When I first fired them up I had to track down rattles all throughout the house It sounded like a storm was coming through! I have them balanced pretty well with the rest of the system... I let Audyssey do its thing and then tweak further with REW, BFD, Rad Shack SPL and an ECM8000, I balance amp gain with input gain to make sure there is no signal clipping at the desired level. I had them running hot at first but with the Dynamic EQ feature its really not necessary, I have since set them more level with the mains... Certain scenes that I have seen dozens of times I've thought "where did this lfe come from". These subs are like ninjas, they stay in the shadows until they are ready to strike... and when they do, you know it!!!!

Highest level I've been at is 6 below reference, notable moments at this level:
Transformers Ironhide flip makes my eyes water.
My hair has began to stand up a few times.
I've felt my shirt move.
Inception has not been this visceral since I saw it in IMAX (I love Inception)
:O

My 2 SVS subs were great, but after having these in the system I'm floored by what I did not know I was still missing. Its truly a new level of bass reproduction!
 

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Hey, great project. Thanks for posting your experience, because I am considering a similar project (IB using the garage).

I am concerned with the motors facing the garage though & plan to place the motors inside the manifold to avoid dirt/dust fouling as well as random things affixing themselves to the magnets.

Does the garage represent issues...i.e. sound leakage into the neighborhood? Seems the garage door would provide little sound suppression.

Do you think I'm being overly paranoid?!?!
 

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Discussion Starter #27
Hey, great project. Thanks for posting your experience, because I am considering a similar project (IB using the garage).

I am concerned with the motors facing the garage though & plan to place the motors inside the manifold to avoid dirt/dust fouling as well as random things affixing themselves to the magnets.

Does the garage represent issues...i.e. sound leakage into the neighborhood? Seems the garage door would provide little sound suppression.

Do you think I'm being overly paranoid?!?!
Hows it going? I don't think you are being overly paranoid about the motor structure... if you have wide enough stud spacing I think placing the motor structure inside the manifolds would be a fine idea, I think it looks pretty cool too. If you can't I would not be too worried about it, these drivers seem pretty tough and when they get to doing their thing dust just flies off anyways, lol. Garage door has not been problematic for me, the only thing that it does is vibrate a bit but you can't hear it in the theater room and the bit of sound leakage just adds to the "infinite" in the baffle, lol. About a quarter of the way down the driveway the Its not very offensive anymore... even with the garage up. Once I tracked down the rattles in the house the overall offensiveness is surprisingly not too bad either. Crazy me is thinking about expanding it with 4 more 18s have not decided yet though.

Hope that helps.
-RMB :D
 

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Crazy me is thinking about expanding it with 4 more 18s have not decided yet though.
Good gravy, a total of (8)! I was thinking about just (2) 18IB3's (on an older EP2500), which would be good for something like 121dB! You mentioned that you've not been above -6 from reference. Are (4) running out of steam at that point?!?!
 

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Discussion Starter #29 (Edited)
Yeah I think its just crazy insurance, probably never getting anywhere near their total output.
at -6 the 4 still have a lot in the tank but my main speakers don't lol, really dynamic films like Ghost protocol make them start to get harsh and thin sounding. I've turned the mains off and run things at reference and the IBs are still doing fine it would seem. Using a good bit of excursion on the "low" stuff but I don't think it's too much in the grand scheme of how much they can move. I just Bought 3 JTR Triple 12s for my LCR, I plan to do a lot more Reference level listening. Man I love chatting this stuff up. :)

-RMB
 

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From the graphs it looks like you have your lowpass set at 80Hz? How do you get the rest of the LFE?
Any concerns with chest compressing bass? Is it still there after you got rid of your box subs?
I am planning a 4 IB318 build but I am a bit concerned about upper bass performance, since the FIs will be the only thing reproducing the LFE information.
 

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Discussion Starter #33 (Edited)
From the graphs it looks like you have your lowpass set at 80Hz? How do you get the rest of the LFE?
Any concerns with chest compressing bass? Is it still there after you got rid of your box subs?
I am planning a 4 IB318 build but I am a bit concerned about upper bass performance, since the FIs will be the only thing reproducing the LFE information.
The response starts to naturally roll off a bit after 80hz so I do set the low pass to match. The other lfe comes from my mains which are JTR triple 12s, I high pass them at 60hz so I get some overlap in that area.

I get better mid-bass with the combo of JTR and IB subs than I ever did with my box subs.

Honestly though if you aren't interested in ultra low frequencies and you are looking for mid-bass headroom, I think the best idea would be a couple of THT folded horns. Problem is they take up a good bit of room and the IB as you know, eats no floors space.

From what I have found is that in order to have a really good mid-bass kick especially if you are EQd flat, you need to be pretty upwards in the volume or running the subs hot by a good bit or a combo of both.

Also do not underestimate the importance of acoustics. long Bass decay times can muddy up the tight punch we want.

The IBs sound really good and can provide very tactile low frequencies that you can feel in your gut however, there are other options that may better provide you with what you are looking for.

-RMB
 

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No, I love my infrasonics! I also love midbass, but my mains handle that bit. What I am concerned with is the fact that I will lose LFE information if I need to set crossover at 80Hz. Now, if it's only a natural rolloff and no nasty breakup noises I can live with it. As far as I know I have no way to let the mains handle LFE above 80Hz. Note I'm talking about the LFE channel, not redirected bass.
Also, I don't know if I'm making a storm in a glass of water here, there may not be much useful information above 80Hz in the LFE anyway.
 

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Discussion Starter #35 (Edited)
No, I love my infrasonics! I also love midbass, but my mains handle that bit. What I am concerned with is the fact that I will lose LFE information if I need to set crossover at 80Hz. Now, if it's only a natural rolloff and no nasty breakup noises I can live with it. As far as I know I have no way to let the mains handle LFE above 80Hz. Note I'm talking about the LFE channel, not redirected bass.
Also, I don't know if I'm making a storm in a glass of water here, there may not be much useful information above 80Hz in the LFE anyway.
I think the redirected bass is part of the LFE signal. If the speakers can handle those frequencies at proper volumes then all should be fine.... there shouldn't be an audio/frequency hole.

A lot of receivers don't have a dedicated high pass setting option for the LFE channel so, when you set a crossover for you main speakers at 80hz I do think it automatically sets one on the lFE in that area too. I could be wrong but I think I read something about this.

So I guess the only way to pump up the 80-120hz area would be to run a dedicated EQ to the speakers.
 

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LFE is a dedicated channel reproduced by the subwoofer. Subwoofer also gets any redirected bass from any other channel. But with my processor (Onkyo PR-SC5508) there is no way to have any other channel reproduce any part of the LFE, unless you have no subwoofer attached.
 

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Discussion Starter #37
I see I see! Does your processor have a dedicated LFE Low pass setting available in the menus?

-RMB
 

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I see I see! Does your processor have a dedicated LFE Low pass setting available in the menus?

-RMB
Yes it does. But it's been confirmed it discards anything above the lowpass setting, it will not redirect to the mains. So to get the entire LFE channel you need to have that set to 120Hz.
 

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Discussion Starter #39
well I'm not sure what to tell ya... I did some more experimenting with mine today and settled on running the lpf at 100hz. When I had my box subs I ran the filter higher and could never notice that much difference, I'm not quite sure how much 100-120 signal is mixed into the lfe channel, but I know it IS spec. I have not felt I've been missing any lfe since my IB subs and my favorite thing about them is not taking up the floor space. If I did it all over again though, I would go Horn and figure a way to have the mouth venting into the room much like the IB.

-RMB
 
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