or Connect
AVS › AVS Forum › Audio › DIY Speakers and Subs › SI 24z build....8 of em'
New Posts  All Forums:Forum Nav:

SI 24z build....8 of em'

post #1 of 675
Thread Starter 
Update 3/3/14...so after many issues in the home construction I am happy to say we are reaching the end and HT build can get started. Long story short, the contractor cost me what the IB space would have cost to construct physically about 2times over. Silver lining....with so many options for good diy subs these days, you can't lose. I have considered options carefully and talked with a few folks that I trust about it.....my 8 SI 24z will be here in a few weeks biggrin.gif

That's the starting point for the new project, where if you jump to page 12, I'd love thoughts on implementations.

Any and all comments welcome and as always, thanks to all!
Edited by ChopShop1 - 3/3/14 at 7:07pm
post #2 of 675
Do you have any size restrictions for the enclosures, or the number of enclosures? Could you go with 12 LLT's, or would that take up too much room space?
post #3 of 675
Thread Starter 
I don't really have a hard and fast size constraint. The only thing I am trying conform to is that the AE thinks that the best response will happen with subs in each corner.....so while I don't have a space issue on the surface, I may if that is our final placement. The front wall is cake with what is now a four foot deep by 11.5ft high and 22ft wide space. The mains will eat up over two foot of width and lots of height each as well, but the majority of the space will be available. After our conversation last night and the changes to room dimensions, the area behind the screen wall could actually lend itself to IB as well. After bracing, framing, drywall etc, it could end up in the 500ft3 range or so. My only concern with it is that I would be limited to all front of the room woofers and if response isn't ideal I don't have much recourse....unless I put a couple of manifolds in the back as well, running into the concession stand area, which will also be treated to isolate sound from the rest of the house.

My initial thought was for like 3 or 4 of the UM or ftw21 in each corner. I guess ultimately I need to wait for the plan drawings and treatment placements to determine how each will fit. Just really trying to get an idea of what I should narrow down to. I haven't looked at any LLT options and honestly, I've never worked with one. I will do a search for threads to see what results have been had with them too.
post #4 of 675
Thread Starter 
I really I have to post a pic of the space, even a sketch, because the room dimensions I thought would work best will not and they have changed since the original plans. Reading MK and others IB builds really has me intrigued as well. I am doing some scale drawings now to see how the measurements for manifolds or arrays would play out based on rear speaker placement, door openings, screen etc. If I have a net of 500cubes behind the screen, that could fit 8 IB3, and then the adjoining room, which is an accesorie room to the HT, will be even bigger. The rear manifolds or arrays would have an entire room of approx 3000ft3, so 8 more could go back there. Is there any issue that you guys know of with having more space behind one set than the other?? I know 10 X vas is optimal, but woud it work like a closed/ported system too, where in the "enclosure" space difference with cause different response?
post #5 of 675
Thread Starter 
Well, after a day of reading I have come to two conclusions: any of the above will be great, and the 24s are going to be just a hair too big to be sure I can move then whoever need be. I am really strongly considering both a 12-16 driver IB or 12-16 FtW21s. I know the 21s sound funny when I say the 24s might be too big, but sometimes inches makes the difference. I probably could fit em' but modeling suggests that the IB or 21s won't give up much to them, especially in these numbers.

I hadn't planned on this, but I'm being coached by a pro who thinks the best response will come with a sub system in each corner Iod the room. The 21s are small enough, haha, that I this doesn't turn out to be the best way, I can accommodate cabs elsewhere in the room. The IB would be tougher to do that with, and for that reason I'm leaning to the 21s. I would love to through 16 Fi 18s or AE IB 15s in there for the fact that I would just live an IB and because it would save me thousands in both drivers and amps.
post #6 of 675
Not sure who "The Pro" is, but I don't really think you can lose going with subwoofers in the four primary corners of the room...and when the subwoofers are a mega amount of large-diameter drivers (IB or otherwise), 'winning' will definitely be the end result! biggrin.gif The Harman White Paper has shown it is a great option. Going this way myself; wish my bonus room above the garage was a larger space, but it is tailor-made for a four corner IB system and will be getting 4 FI 18's and 8 SI 18's...which should provide 'adequate bass' in a 2000 cu.ft. room. Who's "The Pro"? smile.gif
post #7 of 675
Thread Starter 
Have gotten lots of great advice from a few, but on this in particular, Keith Yates has offered up some help. I would be a fool not to take his suggestions I think biggrin.gif

Four Ib18s from Fi or even the 15s from AE in each corner of the room would hopefully provide insane levels of output, even in 8000cubes. My biggest fear, and why I'm talking about crazy numbers of drivers is the separation between each is so great, that I won't get the standard coupling effect....probably incredibly smooth response, with the sacrifice of some output. The fact that the IB drivers are a third the cost and the amps cost would be a third too...we it makes them attractive.
post #8 of 675
Maybe start with 8 IB'ed 21's and if that still isn't good enough, plan for adding more to the IB or two stacks of quad 21's in the back corners.
That would give you 16 21's, I couldn't see that having bad results. You'll need about 8 amplifiers, each on it's own circuit, say 30amps @120v, which would require a 120amp 240v service just for the subs.
post #9 of 675
Thread Starter 
16 21s couldn't possibly leave me wanting....I wouldn't think there'd be any way. I am fully prepared for the electrical load I'll need, but in the Ib, it'd be much less. Each driver would only need about 500 watts or just slightly more. I could end up "only" using 10kw to reach insane output levels. The one drawback, and attraction to the sealed 21s is my front stage placement. If I seal off the majority of space, I'd have to figure it out so that it still allowed for tinkering with toe-in, etc on the mains.
post #10 of 675
Quote:
Originally Posted by ChopShop1 View Post

Have gotten lots of great advice from a few, but on this in particular, Keith Yates has offered up some help. I would be a fool not to take his suggestions I think biggrin.gif

Four Ib18s from Fi or even the 15s from AE in each corner of the room would hopefully provide insane levels of output, even in 8000cubes. My biggest fear, and why I'm talking about crazy numbers of drivers is the separation between each is so great, that I won't get the standard coupling effect....probably incredibly smooth response, with the sacrifice of some output. The fact that the IB drivers are a third the cost and the amps cost would be a third too...we it makes them attractive.

Keith Yates = Pro, for sure. cool.gif I've been pretty impressed with his projects.

Totally agree with your assessment of the IB alignment...'working smarter' is how I like to view it. Can you do an IB in each corner of your room? (not many can).

I wouldn't worry much about coupling with 16 drivers...you'll have plenty of headroom. smile.gif
post #11 of 675
Thread Starter 
I can fit manifolds or arrays in each corner for IB, no problem. I have been looking at the AE IB15s too. What are anyone's thoughts on how they compare to the Fi 18s?? The difference in displacement is not insignificant...the sd on the fi is 50% greater and the xmax is more than that. The IB15 will be much easier to fit, but the Fi can be done. I guess I'm answering my own question with this info, just curious what others think. Also curious about placing the rear of the woofers inside the manifold, which empties into the HT, and facing the cones into the back space....is that ok?? I know it seems like a stupid question, but having never done a high performing IB, I thought I'd ask. I know they say the sound waves are equal on the back space, but wanted to verify. If this is ok, the Fi IB318 are a no brainer. It's more displacement and 16 of them costs less than 8 ftw21s and the power requirements would be soooo much less. Thanks guys!
post #12 of 675
How low are you running your mains? I would put a Ghorn, or two, in each corner if you are crossing your mains down to 60hz.
post #13 of 675
Thread Starter 
Quote:
Originally Posted by Stumbo View Post

How low are you running your mains? I would put a Ghorn, or two, in each corner if you are crossing your mains down to 60hz.

Ya know, I'm not positive yet. A lot will depend on what they are running like, in the room. Problem with that is that if I finish the room construction without taking into account the sub system I'll end up ripping a whole lot of work out to start over. Now with that said, I can't imagine I'd cross as high as 80hz. The mains should have staggering output down below 60hz, so somewhere around that sounds like it'll be about right. I just want to be sure that wherever I do cross, the output capabilities of the subs/mains will match up and blend well, so I'll be careful about creeping down too far and letting the subs run over the mains. With four 15s cruising along in each L/C/R, it shouldn't be much of an issue though. I could fit a Ghorn in each corner if that was the best option...concerned about ULF vs other options though. I have not done as much research on the ghorns as the other stuff though. Thoughts on that?
post #14 of 675
Things that always come to mind are
TH221's single or pairs; bandwidth is only in the 18's but get above that and eek.gif
GH in pair or quads, smile.gif
IB FI18's 6-12, (bang buck $/vas/spl) iIMO best option
IB RE XXX18's 6-12 (when $ no option)
post #15 of 675
In your situation where I know you won't be satisfied with anything less than full tilt to match the SEOSR's, I would strongly consider either:

1) Wall(s) of IB 18's: This is definitely the most cost effective option in terms of raw materials, amplifiers, and woofage required. Downside is construction may be slightly more difficult than multiple sealed enclosures. They will dig as deep as you would like to and require far less power as your stated above.

2) 2-4X G-horns or Orbit shifters: Upside is they are very cost effective considering their output, downsize is size and ability to move to different locations in the room. They will not play that bottom octave like the IB or sealed will, but that's up to you how much you would value that bandwidth.

I don't see how you could go wrong with either of these, but in your situation I might not bother with a bunch of sealed due to efficiency and cost.
post #16 of 675
Thread Starter 
Thanks for the thoughts guys. The IB 18s are really starting to look like a good fit. with 16 of them (four in each corner) I should have extension as low as could be and output to knock me on my a$$ biggrin.gif
Trying to look at different configurations now to see how to run the amps if I go this was. If I can wire 8 of them to a four ohm bridged load of one amp, or four to each channel at 2ohm stereo load, it will put 625w to each woofer and only use two of my Cv5ks. Not only will I not need to buy more amps, but I could actually sell a couple biggrin.gif Not to mention my electric bill will thank me biggrin.gif
625 seems about right for the 18s I think....??
post #17 of 675
G-horns in each of the corners, plus two nearfield. Everyone should try them nearfield at least once for the experience. Your new mains should cover the mid-bass juuuuust fine. The other options aside from the IB will take up a ton of space. What about a couple of rotary subs?
post #18 of 675
Thread Starter 
Muuhahahaha....meet the AE IB18!!!
Fs: 18.4hz
Qms: 5.7
Vas: 632L
Cms: .3
Mms: 250G
Xmax: 18mm
Xmech: 25mm
Se: 1218sqcm
Vd: 4.4L
Qes: .63
Re: 5.6ohm
Le: .41mH
Z: 8ohm
Pe: 500W
Qts: .57
1W SPL: 90dB
2.83V: 91.5dB

New development just for the SEOSR Theater!! hahaha...not really, just great timing. John will have these up on the site and ready to order in the next couple of days. I just had a great talk with him about them and I'm in for 16 or em'!! I will have AE everywhere biggrin.gif The initial plan is to do two dual woofer manifolds in each of the four corners of the room and each at 1/4 from sides/top/bottom. That could change a bit based on instruction, but it's the plan right now.
post #19 of 675
So, um, Chop. How well constructed is your home? :-)
post #20 of 675
I have never been to CT, but I feel a trip in the future.
post #21 of 675
Quote:
Originally Posted by ChopShop1 View Post

Muuhahahaha....meet the AE IB18!!!
Fs: 18.4hz
Qms: 5.7
Vas: 632L
Cms: .3
Mms: 250G
Xmax: 18mm
Xmech: 25mm
Se: 1218sqcm
Vd: 4.4L
Qes: .63
Re: 5.6ohm
Le: .41mH
Z: 8ohm
Pe: 500W
Qts: .57
1W SPL: 90dB
2.83V: 91.5dB

New development just for the SEOSR Theater!! hahaha...not really, just great timing. John will have these up on the site and ready to order in the next couple of days. I just had a great talk with him about them and I'm in for 16 or em'!! I will have AE everywhere biggrin.gif The initial plan is to do two dual woofer manifolds in each of the four corners of the room and each at 1/4 from sides/top/bottom. That could change a bit based on instruction, but it's the plan right now.

Proper. cool.gif

post #22 of 675
Wowzers...this sure lives up to the name of your thread!
post #23 of 675
Quote:
Originally Posted by ChopShop1 View Post

New development just for the SEOSR Theater!! hahaha...not really, just great timing. John will have these up on the site and ready to order in the next couple of days. I just had a great talk with him about them and I'm in for 16 or em'!! I will have AE everywhere biggrin.gif The initial plan is to do two dual woofer manifolds in each of the four corners of the room and each at 1/4 from sides/top/bottom. That could change a bit based on instruction, but it's the plan right now.
Nice eek.gif

I have 8 IB15's and they have tons of output. I can't imagine having 16 IB18's! Mine are in two underfloor manifolds in the front corners of my room.
post #24 of 675
Nicely done! Love AE products made here in Murica!
post #25 of 675
Thread Starter 
Can't even express how psyched I am!! According to John, I should have them in my hands around Christmas, what a wonderful gift biggrin.gif
post #26 of 675
"The initial plan is to do two dual woofer manifolds in each of the four corners of the room and each at 1/4 from sides/top/bottom. That could change a bit based on instruction, but it's the plan right now."

chop, just a heads up...the location of the drivers/manifolds at 1/4 distances is to minimally excite room modes because either the drivers cancel the modes in pairs (for the odd order) or cancel the modes by not exciting them (2nd order). corner placement maximally excites room modes since corners are pressure maximum for most (all?) standing waves.
post #27 of 675
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

"The initial plan is to do two dual woofer manifolds in each of the four corners of the room and each at 1/4 from sides/top/bottom. That could change a bit based on instruction, but it's the plan right now."

chop, just a heads up...the location of the drivers/manifolds at 1/4 distances is to minimally excite room modes because either the drivers cancel the modes in pairs (for the odd order) or cancel the modes by not exciting them (2nd order). corner placement maximally excites room modes since corners are pressure maximum for most (all?) standing waves.

Yeah, I think the way I said it sounds funny reading it back...four locations on each wall.....1/4 from top bottom and sides, based on learning from your posts/comments. I didn't mean right in the corners, although that suggestion has come up too. It's tough because I can't really test it until the room is pretty much built and once that happens, I am kinda locked into the manifold locations. I mean, I could move them, but it'd be a pain. With placement on each side and both front and back of the room, would the same issue present if they were really in the corners, not 1/4 distance, or would the number of locations help with it just as much?
post #28 of 675
here is the quarter distance idea expanded to 16 drivers. not really to scale. just trying to convey the point, roughly.



the reflections from the walls, ceiling and floor create "virtual sources", so it hits you as one massive wall of sound.



and congrats to john j. a little more motor on it probably wouldn't have hurt to get a little more upper end sensitivity because most folks are going to run out of excursion with just a couple hundred watts before they run out of power. but, anyways...not exactly a problem you will have with 16 of them. eek.gif
post #29 of 675
Thread Starter 
I remember the basics from the link you gave me a while back, thanks. I guess it leads me to the question of..do you think all sixteen in the front wall like the first example (but with manifolds) would work better than locations in both the front and back of the room?? Theoretically of course. I really want to implement manifolds to keep from getting unwanted vibrations etc. The amount of airspace in the front wall is less than ideal for 16 but works great for 8 and then the rear of the room will have plenty of space on the other side.

Yeah, there were some compromises, John and I discussed them earlier today. The upside is that they should have a bit more low end than something like the Fi IB318. My hope is that with 16of them, output will be so staggering that I can eq it flat as a starting point and then to taste, all while maintaining disgusting output biggrin.gif If I run out of steam I can always add some more...I doubt it though, hope not
post #30 of 675
"The upside is that they should have a bit more low end than something like the Fi IB318."

they won't have more low end than the ib318. that driver has something like 30mm xmax. since both drivers are infinite baffle variety, very little power is required to push them to their excursion limits. so on the low end, they are both excursion limited (as compared with power limited higher up in frequency).

that said, the manifolds to reduce vibration are a good idea unless you can build that front wall with I-beams (H).

in theory, with the front wall loaded sufficiently, side to side and top to bottom room modes are all cancelled, leaving you with just the front/back wall modes, which with one row of seating are all the same, so the entire row can be eq'd identically and more or less to perfection. with two rows, there is a little tradeoff, but still should be really good.

paulw's octagon (member pnw) is definitely worth another visit. his aren't arranged optimally, but like you will have, there are so many, that optimally doesn't matter so much.

how much space do you have to work with up there? 20 cf per driver models quite nicely as a large sealed/small i.b. with that driver.

and just in case it isn't clear, I think you made a great choice. if all up front with your mains, you will be able to crossover where you want to your mains with headroom out the wazoo...114db 1w/1driver/1m sensitivity in 2pi space, but yours will be much higher because it is effectively creating a plane wave tube in your theater. somebody might be able to help me out on this one for the sensitivity gain, it is at least +6, but I think more, so you will be over 120db 1w/driver/1m and because of the plane wave nature...no rolloff in spl with distance...so 120db+ 1w/driver in your face. eek.gifeek.gifeek.gif


**btw 1w/1driver/1m is my homemade method for reporting total system sensitivity. I think that gives a reasonable comparison where drivers are in the same ballyard for power handling.
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Speakers and Subs
AVS › AVS Forum › Audio › DIY Speakers and Subs › SI 24z build....8 of em'