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Post by chadcummings on May 13, 2008 13:16:14 GMT -7
I am working on designing/building a HT with IB that has dimensions of 8.5'x15.5'x18' for the theater portion and space enough for a 7250 liter IB space. I may be able to use the soffet area over my screen to expand this space to 8000 liters. I want to go with 4 - 15" subs but do not know what would work best to maximize the effectiveness of the space.
I have read so many articles here about xmax and Vas and everything else that my head is spinning.
Please oh great IB gods, smile upon me and give me some advise.
I have a budget of $2500 for my subs, EQ and amp but my main concern is good clean SQ so if I need to change it I will.
thanks,
Chad
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Post by carvernut on May 13, 2008 13:39:03 GMT -7
*cackles and rubs hands together* 2500.00 hmmm, so thats what... 8 FI 18's and 2 EP2500's   ;D first of all, the space you would be using for an IB, is it an attic, a rear room, a basement? from the way you word it, it sounds like a rear room behind the screen correct? and your don't have to worry about SQ, thats why your here... it's the best SQ short of highly expensive diapole systems and your room is about the same as mine, my room is 10 x 9 x 18 with 8 AEIB15's and it's staggering what it can do... especially considering i payed less than 1000.00 for everything |
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Post by chadcummings on May 13, 2008 14:10:02 GMT -7
SQ is my main concern, that IS why I am here.  At least that is what I had meant to say. Yes, the IB space is a walled off room behind the screen. I am lucky in the fact that I am designing/building my basement how I want it. How do you have your 15's arrayed...2 rows of 4 or in manifolds? I guess I can drop my budget down some then. Are you using an 1196 or anything prior to the 2500 or feeding it directly from your receiver? thanks, Chad |
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Post by titch on May 13, 2008 18:20:38 GMT -7
I would do something like this, only with 4 or 8 Fi IB18's. So the mouth of the manifolds open out somwhere inbetween/behind the main speakers.   |
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Post by chadcummings on May 13, 2008 21:09:06 GMT -7
Wouldn't a line array be a more efficient use of the space though?
I am not questioning your judgement, just really not sure, thats why I am asking.
With only 7250 liters, looks like 4 of the 18's would best benefit the limited space, or am I incorrect.
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Post by ThomasW on May 13, 2008 21:33:31 GMT -7
Build manifolds that way output isn't lost as a function of the wall flexing.
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Post by chadcummings on May 13, 2008 22:20:44 GMT -7
If I am looking at the numbers correctly. Using 4 of the Fi IB18's gives me a Vas-total of about 1500. With roughly 7500 liters of IB space that gives me a 5:1 ratio.
Would I be better suited using a different 18 to get a higher Vas:Space ratio or am I missing something.
Something like the Q18 or SoundSplitter would give me a 7:1.
And will I notice a diiference in SQ between them.
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Post by ThomasW on May 14, 2008 10:02:48 GMT -7
Don't spend so much time fixating on the Vas multiplier.
I'm leary of Soundsplinter drivers now that TC-Sounds (they made the SS drivers) is out of business. Mike can replace SS drivers under warranty, but drivers out of warranty can't be reconed. That makes for a very expensive paperweight.
Fi and AE drivers can be reconed/rebuilt. That IMO is an important consideration for the long term
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Post by chadcummings on May 14, 2008 10:44:30 GMT -7
So 2 manifolds each with 2 of the Fi IB18's powered by a Face F1200TS should do the trick then?
And if I have read everything correct, the manifold opening should be Sd*number of speakers in the manifold so each manifold opening would be approx 2420 cm^2.
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Post by carvernut on May 14, 2008 11:00:48 GMT -7
the problem with line array is like Thomas said, wall flex... which generates a 180* out of phase signal and greatly hinders your low frequency reproduction and my system is a manifold with all 8 drivers in a single manifold between the mains at the front of my room. you can see it here: ibsubwoofers.proboards51.com/index.cgi?board=projects&action=display&thread=949i have a Carver TFM-35 bridged with the controller being a BFD 1124... works fantastic although i'm considering a TFM-55 or a T1.5 for more power, the TFM35 is probably only about 800 watts true power. |
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Post by ThomasW on May 14, 2008 14:21:04 GMT -7
And if I have read everything correct, the manifold opening should be Sd*number of speakers in the manifold so each manifold opening would be approx 2420 cm^2. Again the size recommendations are guidelines not absolutes.. If you use standard 16" OC stud spacing the 14.5" opening between studs would be wide enough for a pair of 18"s |
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Post by chadcummings on May 15, 2008 23:00:40 GMT -7
Ok...a flaw in the slaw so to say.
I have read info on the DIY subs, Maelstrom-X and DPL-15, which both have a real low Fs.
I like the Fi IB18's but looking at the DIY products I am now really unsure what to do.
Thomas, or anyone smart with looking at the numbers, can you give me an educated response as to what you would do.
Sorry to keep beating this guys.
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Post by carvernut on May 16, 2008 7:25:57 GMT -7
Ok...a flaw in the slaw so to say. I have read info on the DIY subs, Maelstrom-X and DPL-15, which both have a real low Fs. I like the Fi IB18's but looking at the DIY products I am now really unsure what to do. Thomas, or anyone smart with looking at the numbers, can you give me an educated response as to what you would do. Sorry to keep beating this guys. um... i don't understand, there is no question here, educated response to what?  don't get hung up over the FS, thats simply the resonant point of the driver... it doesn't really make or break your plans, it just means that it is slightly stronger on the lower frequencies than say, a driver with a FS of 33hz |
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Post by ThomasW on May 16, 2008 8:32:50 GMT -7
Sorry but I don't have the time or patience to run an online 'woofer school'. If you want to learn about the design of loudspeakers look to books not an internet forum.
The Maelstrom is way overkill for IB use. It's a outstanding driver for those needing or wanting a high performance driver or two for a box sub. For the cost of single Maelstrom delivered, one can own a pair of Fi IB-18"s and have significantly more displacement.
The DPL-15 isn't yet available, when it is available it will be strong competition for those needing or wanting a bargain 15" driver.
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Post by chadcummings on May 16, 2008 8:39:09 GMT -7
Ok, I been playing with WinISD and the info on each of the subs and have narrowed my pick between using the DIY DPL-15 and the Fi IB18.
The one thing that is leaning me to the Fi IB18 is the SPL levels I will get out of the setup.
The SQ on the plots seem to be very very close so I do not think that is an issue between the two.
The one thing that leans me toward the DPL-15 is its size and how the install and setup will not be as complicated as an 18 setup.
This is my decision point. SPL or ease of setup.
I would either be using the Face T1200 to power the Fi's or the Face T700 for the DPL-15 which is only about $100 difference in price so the power requirements are not going to be a factor.
With the quality of the DPL-15 coming out, as the specs show, the one thing I would love to see is a DPL-18 and what it would do but that is only a dream of mine.
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Post by ThomasW on May 16, 2008 8:54:52 GMT -7
The SQ on the plots seem to be very very close so I do not think that is an issue between the two. Anechioc sims provide no information about sound quality. Not sure what this means. It's no harder or easier to setup either size driver. |
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Post by chadcummings on May 16, 2008 9:04:25 GMT -7
Sorry but I don't have the time or patience to run an online 'woofer school'. If you want to learn about the design of loudspeakers look to books not an internet forum. Last time I checked, forums are used to answer questions and gather other peoples opinions. Your own forum, this section to be exact, is described as "Discussion of subwoofers, subwoofer suppliers, and things specific to the choice of drivers for IB subwoofers" My questions fell within these guidelines. I did not proxy your specific input therefore if you do not want to give it you don't have to. I have been reading my butt off and my brain now hurts from all the information, I came here for clarification and personal insight and experience. Thank you to everyone who has helped me. |
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Post by carvernut on May 16, 2008 11:11:55 GMT -7
hold on, hold up before anyone gets offended please...
i think what Thomas is trying to say is that literally hundreds of people come onto this site, and just start asking questions which have been answered beforehand, many times.
Now i'm not saying you havn't read the forums im sure you have, and i asked alot of questions that would have answered themselves if i had read more... but yes your brain shuts down after absorbing so much info...
but i think your getting hung up on woofer specs and types that we dont commonly use in our aplications due to either, lack of availablility or the major thing, price.
the reason most of us use and/or wanted an IB was because it's cheap(figuratively), easy, and out of sight if you have the required backspace. why use a driver like the Mal-X18 when the AEIB15 just as good of a bass driver unless you literally want to cause major damage to your home? i have 8 myself and can cause more than enough flexes and movments in my walls and ceiling to scare me.
if you want to use the Mal-X or like the Aura-18(argued the best SQ woofer) go ahead it your home and your money, you do what you want with it... we are just trying to save you from getting something you won't need in the long run unless you just want to be able to say you have the biggest and baddest sub on the planet... which in that case go build a horn, like the royal listening device.
the popular drivers in use by our members are used for a reason, they sound good, the perform great, and they didn't break the bank... just bring your worries and thinking down a notch... trust me you dont need to worry so much about the driver as your do the box, and since we've already done the research for you on the drivers all you need is the box... or in this case, no box
IB's sound fantastic... if you havn't heard one then dont get bent outa shape over worries that it wont sound right or how you think it should... trust me an IB is like nothing youve heard yet... very smooth and subtle... and then suddenly agressive and restrained like a high performance sports car, it's like the difference between a stock car with a loud exhaust or a high performance car, one sounds loud and impressive, but the real winner is the one doesnt need to show off to know it's gona win
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Post by chadcummings on May 17, 2008 0:29:39 GMT -7
Serious...thanks for the help. My ignorance and process of education should go to help others in their reasoning when they start looking at IB's as well.
Thomas and everyone...thanks.
I was leaning heavily toward the 4 Fi IB 18's like many had stated but after reading and reading and reading and reading.....and reading.
And getting hung up on numbers and reading...you get the point.
I have decided what I will be doing.
Nothing against the Fi IB 18's as I whole heartedly believe they would be truely amazing.
But, given my 7250-8000 liter space I am going to use 8 of the DPL-15's, 2 manifolds of 4 each, and here is my reasoning.
The Fi IB18 in a 4 pack vs an 8 pack of DPL-15's is only about $40 difference in cost.
With the 8 DPL-15's I gain 37% more Sd over the 4 Fi IB18's while the IBspace:Vas change is very minimal and the total displacement increase is nearly nothing...I know, numbers again.
My thoughts are that given that $$$, Vas ratio, and total displacement remain virtually the same that the increased Sd will be my biggest benefit...but hey, its gonna be awesome no matter which way I do it.
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Post by carvernut on May 17, 2008 8:15:57 GMT -7
yay! another member is going to join the ranks of the 8 15's club!!  ;D and yeah those drivers are gona be crazy awsome for ya... expect an easy 135dB's +... or more |
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