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Fi IB3-18 x 8 and SEOS pure 10 kits! - Page 9

post #241 of 1021
Quote:
Originally Posted by Reddig View Post

Aww man looks great!! Like Christmas morning!
Your Christmases are better than mine.
post #242 of 1021
Quote:
Originally Posted by pitviper33 View Post

Your Christmases are better than mine.
Lmao I could only wish.
post #243 of 1021
Thread Starter 
Mine too! My children on the other hand are spoiled by my parents!
post #244 of 1021
Love the pics, the packaging hasn't changed a bit. Keep us updated, I think you're going to enjoy the final product.

Refresh my memory, .. you've got capability to boost way down in the 10hz range right? I believe they may need some native boost down low, but it'll all depend on the transfer function of the room (the new smaller room). The backspace is a bit on the undersized side, yet your room cubes are similarly modest too.

IB does present somewhat differently in my experience, I hope that's to your liking.

My IB3-18s are pre-redesign, pre 2011 Fi re-tool*. The mfr claims the Xmax wasn't changed, however I always speculated Xmech became a bit more robust. Mine bottomed easily and nastily with 400-500w. Others since the redesign seem to have an opposite opinion, with the same amp, so I'm uncertain what was at play. Maybe their system roll-off prevented the situation, don't know. The redesign had a more significantly bumped back plate, as part of the redesign was a solid pole.

*I don't recall all the specifics, however they moved much of the operation in house whereby they had more control, etc. They claim motor has better thermal capability, less compression. But with multi-driver IBs, it's such a non issue.

Good luck
post #245 of 1021
Thread Starter 
Thanks! I will update here and first post as well.
post #246 of 1021
Looking good James. I'm excited for you!

Any chance we can get detailed pics of the spider, magnets and back plate?
post #247 of 1021
Quote:
Originally Posted by nube View Post

Looking good James. I'm excited for you!

Any chance we can get detailed pics of the spider, magnets and back plate?

I've got several images of my IB3-18s, ... here's a couple images for now. The first one is just an overview up in the attic, showing the drivers, manifold, mounting, etc.

These can be right click/opened and enlarged for more detail.





This second one, looking up from the media room, illustrates my concern for side-to-side rigidity, and how beefy I made the cross brace ... triple 3/4". I don't think three pieces were needed, but wth. My side panels were flimsy before the drivers were mounted. This was by design, and due to minimizing throat aspects. The driver comes right to the edge of both the manifold top, and the ceiling joist at the bottom.



The plan was two manifolds, both front and rear of room. I wanted both capable to be vertically expanded from a quad set, up to four more for 8 total. Both pics were prior to full completion of the project. There's now other changes, including fluffy batts atop the loose blown in stuff, filling in the areas, and additional electrical feeds and re-work of existing.


Anyway, whatever detail you're wondering about, I hope this helps. Granted, these are the older style. The newer ones a similar visually, except the back plate bump is a bit more exaggerated.

Thanks
post #248 of 1021
looking good.
post #249 of 1021
post #250 of 1021
What is the best way to find out where to put the ib sub before you start to put a big hole in your wall or ceiling?
post #251 of 1021
Those images reflect the re-design I referred to.

They brought the basket manufacturing from overseas, to in-house. And you can see, the generic multi application basket in my attic IB image, compared to the more robust, and custom basket that they machine in house.

Fi's Scott Atwell "much beefier than the original with heavier fillets in all corners and where the legs attach to the mounting flange, .... Raw basket costs twice as much as finished Chinese basket, but we are trying to do as much in the US as possible. Beefed this 12 spoke version up quite a bit more."

Fi car audio was started by Scott Atwell, previous owner/creator of RE audio. It's my understanding he designed the über bad-ass RE-XXX. He brings a lot of experience into the design of Fi products. He is his own build house, OEM for several other brands too.

They attempted to incorporate a Neo-Dym magnetic approach to the re-design, but as bad timing would have it, Neo-Dym prices skyrocketed, so they scrapped that and went back to a more conventional approach.

I think the IB3-18 represents a great value in IB subs, it does roll off a bit higher than Janowitz' IB design, but one can compensate for that with the right tools.
post #252 of 1021
Quote:
Originally Posted by Pain Infliction View Post

What is the best way to find out where to put the ib sub before you start to put a big hole in your wall or ceiling?

The best way?

A thorough examining of best practices, combined with test boxes and extensive location testing.

Appropriate acoustic treatment lessens potential issues, as does a multi-location IB approach.

Also, an IB array up front, with ample treatment of the rear wall boundary behind the LP, is a solid technique that should mitigate many issues that originate from the interaction of the rear wall. But, ample treatment is often no small task. If you want more details, PM me as I don't want to clutter up MK's thread excessively. I feel I'm already doing that, want to stay on point.
post #253 of 1021
Ok thanks. I will pm you when I am really serious about starting the project.

Sorry MK for getting off topic.
post #254 of 1021
Thread Starter 
Doesn't bother me.

I believe these will rolloff like my eD subs did. AE drops off at 22 hz and my eD at 40hz nearfield.
post #255 of 1021
those manifolds look nice guys. have either of you a nearfield sweep with the mic directly in front of the manifold?

also, whoever asked about setup:
good start here:
http://www.avsforum.com/t/1486330/new-build-8-x-18-fi-ib3-18/30#post_23640046
and:
http://www.avsforum.com/t/837744/double-bass-array-dba-the-modern-bass-concept/150#post_23757262
and
http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/multsubs.pdf
post #256 of 1021
Quote:
Originally Posted by LTD02 View Post

those manifolds look nice guys. have either of you a nearfield sweep with the mic directly in front of the manifold?

Thanks, it's amazingly solid. cool.gif

As far as sweeps, yeah I've got all kinds of stuff. But I found it's difficult to get a good close mic measurement, similar to what one achieves with a small-sealed close mic measurement. I'll go thru and find something as close to a close mic response as I've got. What I have encountered, it was tough to fully eliminate the room effects (like one can with a 1"-2" close mic measurement).

I'm not sure how much I got closer than about 18"-24" equidistant from all four drivers, out in front of the manifold. I did take some up in the manifold, but IIRC, the pressure effects (or what I perceived as such) within the manifold, led me to pursue mic'ing out front at least a couple inches into the room and out of the "compression chamber". Although sometimes tongue in cheek, I've often referred to my manifold IB as somewhat akin to a dual, co-entrant compression driver.

Despite some hard drive issues, I'll find some appropriate measurements somewhere. If need be, I'll take some more.
post #257 of 1021
"a couple inches into the room and out of the "compression chamber".

that's the one i'd be interested to see. :-)

i've searched around on a number of occasions and never found anything...which i still can't believe. rolleyes.gif seeing the effect of duals in a manifold close mic would be interesting i'm sure to many folks.

did you post a subjective analysis / critique / opinion on them that you could link me to?

thanks bud.
post #258 of 1021
Is there a reason why almost no one is turning one woofer around so its magnet is inside the manifold? The drivers arent silent enough...?
post #259 of 1021
Quote:
Originally Posted by eXa View Post

Is there a reason why almost no one is turning one woofer around so its magnet is inside the manifold? The drivers arent silent enough...?

I didn't out of ignorance of the benefits and now out of laziness. Honestly, my system just seem so low in distortion anyway and I have other issues to tackle first. At some point reversing a sub in each manifold might be a priority but not now. If I would have known better I could have done it that way from the start.
post #260 of 1021
Quote:
Originally Posted by SXRDork View Post

I didn't out of ignorance of the benefits and now out of laziness. Honestly, my system just seem so low in distortion anyway and I have other issues to tackle first. At some point reversing a sub in each manifold might be a priority but not now. If I would have known better I could have done it that way from the start.

How is that better? I'd not heard that before.
post #261 of 1021
Reduction in distortion via cancellation. Only if there is non-linearity between the cone moving inward vs outward that is.
post #262 of 1021
push-pull reduces even order distortion non-linearities in the motor/suspension, but it is unclear how much coupling there would be in an infinite baffle because the whole point of an infinite baffle is the lack of coupling. :-)

http://audioroundtable.com/PiSpeakers/messages/19880.html
post #263 of 1021
There's been several push pull IBs I've seen, I didn't employ mine that way because of simple mounting logistics.

confused.gif

Lack of coupling, ..? What are you referring to? Under 1/4 wave coupling is all I can think of ...

I've seen IBs here at AVS, with an RE-XXX employed push-pull, whereby the basket of the driver 1, was nearly right up into the driver 2 cone. You can't get the acoustic coupling much more efficiently than that?

Also, Wayne's evidence was pretty compelling. Obviously, these benefits depend on a driver particular physical, and magnetic characteristics.

Plus, in the case of IB, the wonderfully low drive currents (not fighting that small box HP limiter) don't lend themselves to the reduction of magnetic flux modulation distortion, that otherwise would be enjoyed by the high currents native to the small sealed. I'm thinking one could enjoy such benefits in an IB, but any of the flux mod non-linearity that can be reduced, is already lower inherent to the alignment.

John, can you elaborate?
Thanks
Quote:
Originally Posted by LTD02 View Post

but it is unclear how much coupling there would be in an infinite baffle because the whole point of an infinite baffle is the lack of coupling. :-)
Quote:
post #264 of 1021
^ ^ ^

Bizarre formatting going on, tried to edit, to no avail

fixed it, weird ...
post #265 of 1021
Thread Starter 
Is this something I should be doing? I have measured my THD with my eD's at 10, 15, 20, 40, and 80hz and I was well under 2% THD at reference. Does it matter when it is low enough anyways? Hell, I was at 5.6% THD at 20hz with a 130 dBs sweep. The 10hz was ay 12%.
post #266 of 1021
Quote:
Originally Posted by MKtheater View Post

Is this something I should be doing? I have measured my THD with my eD's at 10, 15, 20, 40, and 80hz and I was well under 2% THD at reference. Does it matter when it is low enough anyways? Hell, I was at 5.6% THD at 20hz with a 130 dBs sweep. The 10hz was ay 12%.

Maybe down the road ... it'd be a nice experiment, ... if you can get to the driver's mounting, could be tight, that's why I didn't.

You hit on it, is it audibly worth it? Current induced flux mod is already low in an (8)18 IB, so much of the nulling is possibly soft part related or basket aero effects maybe.
post #267 of 1021
Thread Starter 
OK guys the framing is done! Now I have to repair the ceiling and clean the up the area to get all the wiring ready. I also had a change in plans and I reinforced the wall even more because now I am installing arrays. They will be spread out the baffle wall up near the ceiling and down near the floor. Every single frame is double studs and around where the woofer inserts will be triple studs. I have 2x4's running from baffle wall to front wall. I will also had motor supports too! I have to take a pic of the framing. My theater is a mess! Getting closer though and maybe just in time for Pacific Rim. It should be loud even though it has a 20hz HP on it. My first whole movie will be oblivion since I have not seen it at home yet.
Edited by MKtheater - 10/11/13 at 11:08am
post #268 of 1021
Why did you switch to an array? I have manifolds with two sets of dual opposed subs in each manifold. The manifolds are completely inert. When we had the Omaha Home Theater Tour last year I had all my furniture plus about 25 people in the room. That is over 2 tons on the floor! My floor easily flexed during the demos - especially during Flight of the Phoenix. This is just from the pressure of the back wave/front wave without any driver force. I can't imagine now adding driver force to the baffle wall in addition to the sound waves generated by 8 18" drivers.

I guess Brian Owens did okay with his build: New (8) 18" Fi IB3 IB build







post #269 of 1021
Thread Starter 
Yes I have been looking at many builds and most people are getting away with walls that are not even close to what I am building so I figure why not go for the arrays now. I mean my Baffle wall and space I created was like building a massive sealed box with the same bracing a sealed box would have.
post #270 of 1021
Quote:
Originally Posted by MKtheater View Post

OK guys the framing is done! Now I have to repair the ceiling and clean the up the area to get all the wiring ready. I also had a change in plans and I reinforced the wall even more because now I am installing arrays. They will be spread out the baffle wall up near the ceiling and down near the floor. Every single frame is double studs and around where the woofer inserts will be triple studs. I have 2x4's running from baffle wall to front wall. I will also had motor supports too! I have to take a pic of the framing. My theater is a mess! Getting closer though and maybe just in time for all my re-bassed movies and Pacific Rim. It should be loud even though it has a 20hz HP on it. My first whole movie will be oblivion since I have not seen it at home yet.

Nice the baffle wall is gunna look super badass now! Glad you doubled up on support.
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