Ok, I am in planning and purchasing mode, I've done a lot of reading here and after much learning much about IB subs here - I have the bug. I have made up my mind to do it and shore up the wall to reduce the vibrations. I will be ordering components near the end of November for a build to start Dec and finish at the end of Dec - My company has a mandatory vacation period one week at the end of the year - so the idea is to spend that week finishing up the subs and be ready for a new year of bass.
My current thoughts on setup are the following based on what I have read here:
- minidsp - was looking at 1124, but minidsp is more....geeky??
- Behringer EP4000 - good old standard with plenty of true RMS power
- 4 Fi IB318 18" drivers (I have over 50 * VAS behind the wall - so I am good there)
- one or 2 manifolds - have not decided - more on that later
This appears to be what many people have gone with in the threads.
My main goal is to have something that is great for both music and HT. I have a Magnepan setup right now and they are not the best HT speakers and blending the Magnepan 3.6 and subwoofers is near impossible. But I have read that IB subs are different in that way. I really hate one note bass and bass heard that is the result of cabinet resonances and do know what a sub is supposed to sound like. My biggest fear with and IB sub is that it is going to shake the front wall badly(just from the air pressure) - and that will affect the sound. The front wall is a staggered stud wall and as such is more prone to vibrations. I will have to do some sort of stabilization of the front wall.
One thing I would like some advice on before I order the drivers(and begin the few weeks wait) is should I get the 2ohm or the 4ohm version of the FI IB318 drivers?: http://store.ficaraudio.com/ib318
Per the driver wiring diagrams on this site I believe I could get 4ohm or 8ohm bridged configuration with either the 2ohm or the 4ohm drivers. It that is true - which is better - is there a difference? I guess there is less windings on the 2ohm version?
Thanks
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Spoiler - here is the finished front line.
Whether you get the S2's or S4's will depend on how you want to run the amp. A pair if S2's can be wired for a 4 ohm load, one pair to each channel of the amp. 4 S4's can be wired for a 4 ohm load and the amp would run in 4 ohms bridged mode.
You want to avoid a 2 ohm load on a EP4000, if pushed hard it will kick out on thermal overload.
Robo266317 also helped out with this........Simply wire two pairs in series and then wire the those in parrallel.
eg. (from http://www.bcae1.com/spkrmlti.htm )
Thanks for your help. I ordered the ep4000 and 4 IB318 drivers today.
My original thinking was to put 2 manifolds under my screen on the right and left side, but it turns out that I would have to saw through about 8 inches of concrete to do so. I have never sawed through concrete. So I am contemplating the design you see below. The idea is to output below the center channel speaker that is attached to the wall.
The cube holding the drivers is 2' X 2', but could be wider if I need a bigger output hole. The current design opening into the room is 24" X about 11". The blocks that the manifold is sitting on are 4" tall.
Your manifold opening, which is 264 square inches, should ideally equal the total area of your drivers, which is 750 square inches. Your manifold is 35% of the drivers Sd, you need to go bigger.
Yes, you need to go bigger as Mike suggested. You are basically horn-loading your subs with this configuration. The response can be simulated using Hornresp program but it would be much more predictable if you could enlarge the area to at least 4x sd of Fi IB318
In my build I'm planning on similar config but with 2 manifolds. Each one with 2 opposed IB 18s. They will be flanking the mains. Makes it a little easier to get the opening required.
Amazon is screwing me over. I ordered the ep4000 and it was in stock. Usually, things ordered from amazon and in their warehouse are shipped immediately. My order is awaiting fulfillment for the last couple weeks. May have to order it somewhere else. It's a shame because $275 new seems to be a very good price.
Ficaraudio is taking their usual time in building the ib318s.
In my build I'm planning on similar config but with 2 manifolds. Each one with 2 opposed IB 18s. They will be flanking the mains. Makes it a little easier to get the opening required.
What is the difference in output in one versus two manifolds? I know if you have two, some room nodes may be smoothed out, but otherwise, what is the difference?
Also, is there any reason NOT to have the backs of the drivers exposed to the home theater side of the manifold? I The physics part of my brain thinks it should not matter, but is the output somehow affected or is there turbulence noise from the supports?
My main goal is to have something that is great for both music and HT. I have a Magnepan setup right now and they are not the best HT speakers and blending the Magnepan 3.6 and subwoofers is near impossible. But I have read that IB subs are different in that way. I really hate one note bass and bass heard that is the result of cabinet resonances and do know what a sub is supposed to sound like.
You have chosen the about the best possible option to mate with your Magnepans. I suppose it could be easily argued that dipole bass would be a better match, but simply forget about it also working for HT unless you have 20+ big drivers.
I have a set of 3.6's too and was going to use them in a dedicated 2-channel system in my HT room (paired with an 8 18" driver IB), but the more I think about what a hassle it will be to drag them in and out of position, I'm not so sure I want to deal with it. LCR for the theater-side of things is Yorkville U15 Unitys, and the more I listen to them, the more I am considering forgoing the dedicated music setup. I do love the Maggies -- absolutely wonderful speaker -- but they definitely don't do HT dynamics like I desire.
I might need to kick the baby out of what used to be my dedicated office so I can have a separate dedicated 2-channel system again, or maybe just build a bigger house!
You have chosen the about the best possible option to mate with your Magnepans. I suppose it could be easily argued that dipole bass would be a better match, but simply forget about it also working for HT unless you have 20+ big drivers.
I have a set of 3.6's too and was going to use them in a dedicated 2-channel system in my HT room (paired with an 8 18" driver IB), but the more I think about what a hassle it will be to drag them in and out of position, I'm not so sure I want to deal with it. LCR for the theater-side of things is Yorkville U15 Unitys, and the more I listen to them, the more I am considering forgoing the dedicated music setup. I do love the Maggies -- absolutely wonderful speaker -- but they definitely don't do HT dynamics like I desire.
I might need to kick the baby out of what used to be my dedicated office so I can have a separate dedicated 2-channel system again, or maybe just build a bigger house!
Yeah, the maggies are unbelievable. I listen to a movie and miss the some of the dynamics, but it sounds like you are inside the movie. I keep having these WTH moments of who is in my house. Then I listen to music and mostly forget about the HT dynamics difficulties. I am also afraid of blowing a driver on the maggies. I have blown a couple fuses already. I am waffling on replacing the setup with hybrid ribbon/cone speakers like the Monitor Audio PL200 or PL300.
How would you describe the Yorkville U15 Unitys sound? I have never seen those before.
But seriously, get the baby out of there.:bigsmile:
Yeah, the maggies are unbelievable. I listen to a movie and miss the some of the dynamics, but it sounds like you are inside the movie. I keep having these WTH moments of who is in my house. Then I listen to music and mostly forget about the HT dynamics difficulties. I am also afraid of blowing a driver on the maggies. I have blown a couple fuses already. I am waffling on replacing the setup with hybrid ribbon/cone speakers like the Monitor Audio PL200 or PL300.
How would you describe the Yorkville U15 Unitys sound? I have never seen those before.
But seriously, get the baby out of there.:bigsmile:
The Yorkvilles -- once you experience a movie on a high-efficiency speaker with virtually unlimited dynamics (in a typical home room setting), it's hard to go back to a regular speaker. I will preface that these are marketed as a 'pro audio' speaker, but the Unity Horn is the brainchild of Tom Danley and has very good hi-fi bones as well. These things have a 98 dB sensitivity rating and are ready to explode whenever there is any sort of transient or peak. I've only had them a few months and they are in a temporary install, but I've been very impressed with their musicality as well as the expected superb performance for HT. It's not that I didn't expect them to be good, just maybe not as good as they are...and this without any sort of tweaks (biamping, crossover adj., or eq).
I totally know where you are coming from regarding the Maggie's realism, but it does sound like you're getting precariously close to doing some damage to them. :gulp:
The Monitor Audio's are great speakers -- haven't heard the new ribbon stuff, but have read many good reports. I still own 6 MAG 903 rosewood mini-towers that were purchased 8-9 years ago that helped cement my love for speakers.
Don't worry too much about my lack of a dedicated 2-channel room -- the room the Unitys are in right now has a permanently placed set of LS-6 line arrays sitting right behind them. I don't have any pics of them in the current system as the room they are is in a constant state of flux, but this is the day I brought them home...had to get them out of their boxes and let them stretch their legs for a totally impromptu jam session right near the center of my living room. They ended up sitting like this for about a week.
The baby (totally unexpected & the first girl after 4 boys!) will get to keep my office as her room until her 20-y/o brother pulls his head out of his keister and leaves the nest.
I don't think you need to brace the wall at all. The drivers are dual opposed in your manifold, and there should be no mechanical forces at all against the wall.
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