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Fi IB3-18 x 8 and SEOS pure 10 kits! - Page 2

post #31 of 1021
"I think the more drivers used with IB the more trouble your going to have keeping the baffle from flexing."

i'm not sure what he is planning/thinking, but with typical i.b. manifolds, the drivers are dual opposed to cancel out vibrations.

that just leaves the problem of the whole frig'n wall vibrating...



"MK, wtf, you completely lost the boner with the 24's?"

:-)
post #32 of 1021
If he builds quad opposed, there will be no issues.
post #33 of 1021
Thread Starter 
Yes I was thinking 4 manifolds placed like the picture.
post #34 of 1021
Quote:
Originally Posted by LTD02 View Post

"I think the more drivers used with IB the more trouble your going to have keeping the baffle from flexing."

i'm not sure what he is planning/thinking, but with typical i.b. manifolds, the drivers are dual opposed to cancel out vibrations.

that just leaves the problem of the whole frig'n wall vibrating...



"MK, wtf, you completely lost the boner with the 24's?"

:-)

Quote:
Originally Posted by N8DOGG View Post

If he builds quad opposed, there will be no issues.

Oh nice yes that will definilty work than. I forgot about the dual-opposed option.
post #35 of 1021
Thread Starter 
It is official, I ordered 8 Fi IB3 18's. I was going to get 10 just to double up the 13's I had but after looking at sims I will double the spl at 10hz and even more at 5hz. Like I need more LOL. I never used the 36 liters as it was so now I will have almost 58 liters coasting along to 3hz! I start the wall frame today!
Edited by MKtheater - 8/19/13 at 7:44am
post #36 of 1021
Paint me jealous. smile.gif I can't wait to see these come alive!
post #37 of 1021
Thread Starter 
This should be plenty for my 2100 cubic foot room. Sealed too! My 36 liters of eD drivers ripped it apart! Of course one of the best things people say to me about the experience is that the room makes no noise during all that bass! Just pure bass!
post #38 of 1021
Awesome, look forward to your impressions!
post #39 of 1021
Looks like a cool project for that room- something new. We may not actually see 24"s shipping for a while, and we all know eventually you'll try them out. Might as well do something in the meantime! tongue.gif

I was going to suggest you might as well use this reworking to search for improvements in your system's roll-off. Find components that minimize this, as you clearly have all of the output there waiting to be used.

What does your chain look like right now, and have you measured the effect of each piece separately and summed?
post #40 of 1021
Quote:
Originally Posted by MKtheater View Post

This should be plenty for my 2100 cubic foot room. Sealed too! My 36 liters of eD drivers ripped it apart! Of course one of the best things people say to me about the experience is that the room makes no noise during all that bass! Just pure bass!

Ahh, I see you're going with eight 18's now. Overall I think this might be a better plan for your room, James. Especially considering the quad sets of opposing drivers. Should be interesting but I wonder what the gains will be being you have soo much unused headroom with the twelve 13's. Oh well. I'm still interested and love what you do.

Now I'm just trying to think ahead of you and figure out what will eventually replace this new IB system. tongue.gif
post #41 of 1021
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post #42 of 1021
Quote:
Originally Posted by MKtheater View Post

It is official, I ordered 8 Fi IB3 18's. I was going to get 10 just to double up the 13's I had but after looking at sims I will double the spl at 10hz and even more at 5hz. Like I need more LOL. I never used the 36 liters as it was so now I will have almost 58 liters coasting along to 3hz! I start the wall frame today!

You can't compare like this, ie., an IB to small-sealed comparo. Due to the way sealed box mimics a HP, and how the amp power comes into play, it's just different. Will it matter here, no, not really. Because either config got you the clean SPL you wanted. For my money however, there are other considerations too.

For example, the eD drivers were so very small in diameter, I think you notice a higher quality sound with a more linearized inductance,..as 8 of these will not encounter the excursion the drastically smaller drivers were seeing. Also, the wave-launch will be more purely executed into the space with the baffle wall. Your box subs had acoustic energy leaving the cone, both launching forward, and hitting the wall behind, then launching forward ... thus some summation less than optimally with regard to phase response at the top end of their coverage. This is critical due to blending optimization with mains, etc. It'll just be a more optimal wave-launch wrt time/impulse, phase integrity etc.

Unfortunately you will not have the theoretical ideal infinite backspace. But as far as latent backspace energy encountering the cone, they'll have a fighting chance if you damp the hell out of the volume with fluffy.


Quote:
Originally Posted by MKtheater View Post

This should be plenty for my 2100 cubic foot room. Sealed too! My 36 liters of eD drivers ripped it apart! Of course one of the best things people say to me about the experience is that the room makes no noise during all that bass! Just pure bass!

This is nice, the lack of structural moans and groans.


Quote:
Originally Posted by Scott Simonian View Post

Ahh, I see you're going with eight 18's now. Overall I think this might be a better plan for your room, James. Especially considering the quad sets of opposing drivers. Should be interesting but I wonder what the gains will be being you have soo much unused headroom with the twelve 13's. Oh well. I'm still interested and love what you do.

Now I'm just trying to think ahead of you and figure out what will eventually replace this new IB system. tongue.gif


Once properly blended, etc, I'd bet it'll be better. Aside from the latent energy component, the more idealized acoustic transfer and wave-launch at the top end of the subs range should allow this iteration to shine a bit better than before. Also, those little eD drivers are beastly, but compression will be less an issue here for two reasons; dramatically more swept area, and dramatically more sensitivity in the bottom octaves.

My take.
post #43 of 1021


If you do a baffle like this can you make it large enough to accommodate a push-pull arrangement?

If you have the time & energy I'd love to see a comparison even if it was only done with one pair (with the other ports blocked?).
post #44 of 1021
yes. that would be no problem. just flip half the drivers so the magnets are inside the manifold. the picture isn't to scale either. just to give an idea of what we were talking about a while back.

wayne Parham did a test in a horn loaded sub, much like the lab horn, with one driver reversed. it works. even order distortions were reduced significantly.
post #45 of 1021
"It is official, I ordered 8 Fi IB3 18's. I was going to get 10 just to double up the 13's I had but after looking at sims I will double the spl at 10hz and even more at 5hz. Like I need more LOL. I never used the 36 liters as it was so now I will have almost 58 liters coasting along to 3hz! I start the wall frame today!"

bravo mk!
post #46 of 1021
Thread Starter 
FOH,
Man, you know what the hell you are talking about! My phasing was bad at the crossover region before as you said and distance delays fixed it pretty good without EQ. What worked was setting the distance to the subs at half what they really were and it smoothed out the crossover area. Yes, I have wanted to do a Baffle wall for a while now just because of the lack or rear wave. My front wall has very thick bass traps and insulated soundboard wall to wall but now I will line the whole thing with 2 inch roxul 60 from ATS acoustics. The wall will be made of MDF and it will be anchored to the concrete floor and the 10 inch planks above! I will also brace the needed areas just in case. I can tell you guys that adding the sound board, which is something unique to my room, has made every single rattle or creak or moan go away! The noise floor is very low and the loudest thing in my room is the projector. The guy who bought my eD subs will start a thread when he puts together his theater and will comment on my room. The funniest thing was how well built those eD cabs were, they literally ripped apart his rental crossover trying to fit them in! The subs were fine.
post #47 of 1021
MK, how did you attach sound board?
post #48 of 1021
Thread Starter 
I have sound board behind the drywall and in front of it, all screwed in like drywall.
post #49 of 1021
Gotcha, I used some just like that in my last theater.
post #50 of 1021
Thread Starter 
It works like drywall but rattle and echo free. Of course it is too weak to replace drywall unless your studs are very close.
post #51 of 1021
Thread Starter 
The basic frames are done. Will start some MDF and cut out for holes tomorrow with bracing. I probably have a couple weeks before I see any drivers. I have wanted a baffle wall for ever and this IB gives me the chance or excuse! I will setup the manifolds like the pic shown and guess what, it fits on the sides of my center channel! Maybe a couple inches off. Pretty good.
post #52 of 1021
the larger that you can make the manifolds, the better. something like 24" tall and 16" wide (if that's what the studs are on) should be good for each manifold. I don't think that there is any downside to building them too big (assuming that they are very well built so they don't have any flex), but problems could possibly creep in if they are built too small.
post #53 of 1021
Thread Starter 
I could build too big manifolds with 4 drivers each or should I separate them and them some bracing in between? I have a 74x24 space available for both sides of the center channel. I will add braces for whatever space I don't use both vertically and horizontal. Since I am using MDF for the surface(maybe ply instead?) do I need acoustic material on the surface? I know with plywood I wood. Plywood is cheaper unless I use oak hardwood. My lowes has the MDF for $35 and the oak for $55. 4 sheets will cover the frame(one layer). I buy the stuff tomorrow, any ideas before I purchase? Oh, I will start to take pics soon, it is a mess right now.
post #54 of 1021
Quote:
Originally Posted by MKtheater View Post

It is official, I ordered 8 Fi IB3 18's. I was going to get 10 just to double up the 13's I had but after looking at sims I will double the spl at 10hz and even more at 5hz. Like I need more LOL. I never used the 36 liters as it was so now I will have almost 58 liters coasting along to 3hz! I start the wall frame today!

Right on man let the games begin!!!
post #55 of 1021
Quote:
Originally Posted by MKtheater View Post

I could build too big manifolds with 4 drivers each or should I separate them and them some bracing in between? I have a 74x24 space available for both sides of the center channel. I will add braces for whatever space I don't use both vertically and horizontal. Since I am using MDF for the surface(maybe ply instead?) do I need acoustic material on the surface? I know with plywood I wood. Plywood is cheaper unless I use oak hardwood. My lowes has the MDF for $35 and the oak for $55. 4 sheets will cover the frame(one layer). I buy the stuff tomorrow, any ideas before I purchase? Oh, I will start to take pics soon, it is a mess right now.

Excited to see the pics. Im curious as to how your attaching the baffle wall to the ceiling and floor? Thanks man.
post #56 of 1021
not sure if it matters if the manifolds are combined vertically except for maintaining structural rigidity. i suspect the location of the drivers is more important with respect to the room dimensions. i would build the manifolds with plywood and brace the snot out of the whole thing. the entire front wall is essentially the front side of a giant sealed subwoofer, so brace it up as though that's the case. 2x6 construction wouldn't be overkill.
post #57 of 1021
Thread Starter 
I think I will you use plywood for the whole thing and then add acoustic material.

I basically screwed in pressure treated 2x4's into the ceiling planks and concrete floor. Everything else connects to that. I have to leave huge gaps for my big speakers and manifold holes so the key is bracing underneath and In between. Making door and window frames so to speak. So I will use two layers of plywood for the manifolds and 3 layers for the front wall.
post #58 of 1021
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post #59 of 1021
Quote:
Originally Posted by FOH View Post

You can't compare like this, ie., an IB to small-sealed comparo. Due to the way sealed box mimics a HP, and how the amp power comes into play, it's just different. Will it matter here, no, not really. Because either config got you the clean SPL you wanted. For my money however, there are other considerations too.

For example, the eD drivers were so very small in diameter, I think you notice a higher quality sound with a more linearized inductance,..as 8 of these will not encounter the excursion the drastically smaller drivers were seeing. Also, the wave-launch will be more purely executed into the space with the baffle wall. Your box subs had acoustic energy leaving the cone, both launching forward, and hitting the wall behind, then launching forward ... thus some summation less than optimally with regard to phase response at the top end of their coverage. This is critical due to blending optimization with mains, etc. It'll just be a more optimal wave-launch wrt time/impulse, phase integrity etc.

Unfortunately you will not have the theoretical ideal infinite backspace. But as far as latent backspace energy encountering the cone, they'll have a fighting chance if you damp the hell out of the volume with fluffy.
This is nice, the lack of structural moans and groans.
Once properly blended, etc, I'd bet it'll be better. Aside from the latent energy component, the more idealized acoustic transfer and wave-launch at the top end of the subs range should allow this iteration to shine a bit better than before. Also, those little eD drivers are beastly, but compression will be less an issue here for two reasons; dramatically more swept area, and dramatically more sensitivity in the bottom octaves.

My take.

I disagree with most all of the IB hype I've read over the centuries. smile.gif

Here are excerpts from one of the flowery IB advocate speech writers:
Quote:
The absence of distortion from the IB allows the fundamental to be clearly exposed rather than obscured by false harmonics. No single low frequency tone is ever involved in the reproduction of sound so the false harmonics (of other subwoofers) are as complex as the input signal itself.

The unwanted and artificial hash produced by most subwoofers has its own frequency response and phase superimposed on the speaker's output. The greater the clarity of the subwoofer the greater the sense of realism because nothing is added which wasn't in the original signal.

If any proof were needed of the IB's greater clarity, realism and low distortion then one only needs to listen to the great pipes of the organ being reproduced.

Wow. It would certainly be boffo to see some measurements of an IB that even approach proving this sort of wild claim, which is, sad to say, typical of the IB hype I've read over the years.

All of the Fi drivers that have been measured to date show very high inductance, just as you would suspect they might. The IB has more VC than those that have been measured (and used in small boxes by myself) and no additions to counter the inductance, so the conclusion must be that it has the highest inductance of all of the Fi drivers.

The size of the box the IB3-18s are placed in has zero effect on the roll off or harmonics that result from high inductance, thus, it's crossover region sonic signature will be unaffected by placing them in an IB vs an in-room closed box.

"Will it matter, here, no, not really." <===This is the part I agree with. cool.gif

I've posted in the past that inductance problems are easily overcome, but the point is that they aren't overcome by increasing the size of the box.

What we hear is frequency response. Group delay, phase and the majority of harmonic distortion are derived from the FR in-room. Match the FR and there is no audible difference, much less anything near what is being described by the IB-ers.

Compression is the result of poor design, the size of the box being irrelevant. Push any sub beyond is normal operating parameters and it will compress.

8 x 18" driven by 14KW burst power in 2000 cubes is the key design here. Box size makes no difference.

Sensitivity resulting from box size is a see-saw. Increase box volume and the low end is easier to drive to Xmax, but the top end will never reach its potential for lack of available power. Increase available power for the top end and the low end will be driven beyond Xmax. If limiters are employed to remedy the situation, compression is the result. If HPF is employed to remedy the situation, FR (thus, BW, GD and everything derived from FR) suffers and 'more realism' disappears.

That leaves 2 choices; a) Decrease box volume or b) Increase displacement/power handling.

The choice for most IB-ers is add displacement. Good choice, as it is for any system.

Since we hear FR mores than any other parameter, having placement options is a big. Even if one takes the time to painstakingly locate the IB manifold, there's an assumption that the room acoustics will never change (furniture, furniture layout, monitor type/size, hardware rack, flooring, seat position, etc.) or the type, size and parameters of the driver compliment and that those optimal manifold locations are logistically possible.

I'm sure James will like the result. Fi drivers are well designed and built for the $$ and the inductance will not be an audible problem, in the final analysis.

Another important parameter for proper in-room FR is the signal being fed to the drivers. James has recently changed pre/pros and noticed an immediate improvement, but, like most everyone who posts in this forum, fails to measure the signal chain response. I hope he does instead of the usual blame being placed on some other part of the equation.

Here's a simple guide to how to do that for anyone interested:

post #60 of 1021
I disagree with IB hype as well.

For that matter, I disagree with any such hype, be it IB, small-sealed, vented, horn loaded, any approach.
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