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Discussion Starter #1
Fried my brain looking at all the different subs here.

I think I'll go with an LLT design. Not sure how to determine volume, port specs/location, driver type/location, construction details, and anything else.

From what I've read, I think I can go with one 18" SW, or two seperate 15" SW's. (either option being LLT's)

Would it be possible/advantageous to go with two seperate 15" SW's, with two different tuning points, one @~15htz and the other ~12htz. point being two different low freq tunes?????????

1. my budget will be ~$1000, + or - .
2. my desired location is under screen between mains. area=6'w x 2't x ~3'd. total area allowed.
3.room size is 12'w x 23'd x 8't. ~2200ft3
4. use will be 100% HT, and really want to hit those low frequencies easily.
5. I like to watch movies @ high volume, and my current 12" klipsch isn't delivering enough bass to match.
6. Appearance doesn't matter.
7. timeframe is no big deal, It will probably be several weeks before I can start construction anyway.



Any questions that will help you advise me, just ask.
thanks,
Mike
 

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I think I'll go with an LLT design.
my budget will be ~$1000, + or -
area=6'w x 2't x ~3'd. total area allowed.
I like to watch movies @ high volume.
You have the option to go with a pair of 18 inch LLT's. The Mach 5 Audio IXL-18 in 12.5 cu.ft tuned to 15 hz would qualify as a LLT. A pair of these would more then fulfill your "high volume" needs. The subs are $265 each, shipping included. Powered by a Behringer EP2500 amp for $300, you would be well within your budget.
 

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Discussion Starter #4
Mike P. I'm new to all this, but in the "LLT explained" thread, Steve states that I would need twice that volume for an 18". I'm willing to go either direction, one 18" or two 15"s, whichever config reachs the low notes and still covers all movie range bass the best. Thanks for the reply and hope I'm not coming across as rude or know it all. I'm just always nervous about getting a big project right before I start. Oh yea, does port tune Fr(dia and length) correlate to just box volume or box volume and deminsions?
thanks again
Mike P
 

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The volume required is dependent on the specific sub. The IXL-18 requires less volume then other 18 inch subs. 12.5 cu.ft works well for a IXL-18 but you can increase the volume if you wish since you do have the room to do so. It's entirely up to you, but why limit yourself to one 18 or two 15's when you have the budget and box volume necessary for two 18's that would be far superior in low end output especially since you like it loud in a 12'w x 23'd room. The IXL-18 is out of stock at the moment but should be available shortly. The IXL-18 is known as the "best bang for the buck", I have a pair myself.

I'll ask Steve to join in here to put your mind at ease. Being nervous is a good thing since it makes you cautious, less chance of mistakes being made.

Port diameter and length correlate to the box volume. Port length controls the tuning frequency. Port diameter controls the air speed.

To give you an idea, click on the link in my signature to see a Database of what subs have been built.
 

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Hi folks I work with Mike (nitble) and we have been talking home theater stuff for some time. Mike is a hard core DIY guy like me. Also like me he doesn't always have time to dig into a lot of theory. We work 4 and 5 12 hour shifts at a time minimum with no internet access so our free time is more about doing than studying. We have both been looking at subs from Fi car audio and they too are reasonably priced and available now. Even though I have an IB I would be interested in building an LLT to compliment my dual 15" ascendant audio atlases. I don't know if that union could meld together sound wise but I would be willing to try if some body with some expertise could say yes it is fisable. I have enough room to build 2 subs at 26 liters each as I have a false wall with a couple openings to fill. I have been waiting on the Fi cars 22" subs to come in but they haven't yet. I am wanting a new project in the theater.
Disclaimer: Any misspellings or gramatical mistakes due to a couple burbon and cokes. Yeah it was one of those days.
 

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From what I've read, I think I can go with one 18" SW, or two seperate 15" SW's. (either option being LLT's)
Two IXL 18s as Mike mentioned would be really nice - there's also a 21" Maelstrom that will be coming out in a few months - not sure on your time frame. You also have the Maelstrom 18", the CSS 15", the FiCar Q18s, the Shiva X 15"......lots of options.

Would it be possible/advantageous to go with two seperate 15" SW's, with two different tuning points, one @~15htz and the other ~12htz. point being two different low freq tunes?????????
Definitely possible, but not advantageous. If the bottom ends are mismatched between two subs, then the summed bottom end output will be weaker than higher bass frequencies.

but in the "LLT explained" thread, Steve states that I would need twice that volume for an 18".
It varies from driver to driver. 'Most' high excursion 18s like something at or above 600 liters, but that doesn't mean they all have to.

Oh yea, does port tune Fr(dia and length) correlate to just box volume or box volume and deminsions?
Just volume. That said, you'll want to ensure ample clearance room around both port openings.
 

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Discussion Starter #8
OK! been playing/learning winISD. You thought I'd have some more questions, huh? I DO!

Building two boxes @ ~ 32"x32"x24" will give me ~13ft^3 functional volume each, with a FiQ18" in each.
The only port that could fit in the box and give me a 13hz tune is 30" long and 6"dia?

1. does that dia sound right?
2.would it be acceptable to align the port diagnally in the box? I know the end of the port needs good clearance(~6")!
3.Where's a good construction thread covering more detail? ie. box stuffing, speaker vs port location, and other stuff I don't know to do!

thanks for all the help Mike P and Steve C.
Mike
 

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For $1,000 you could also do a Passive Radiator set-up with either the Maelstrom 18" sub or the new AE AV15X sub. Either one will cover your space with no problem and be in the 7-9cf range, in case you wanted to build something smaller with great performance.
 

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Discussion Starter #12
OK, so for dual ~13ft^3 boxes, which ~$300 18" is compatible for a 13-15hz tune?

or should I look at getting 15"s to match the "what is LLT" volume needed. and what 15s are good for the 13ft^3?

I plan on using the EP2500 as recomended to power them.

thanks,
Mike
 

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Is 13ft^3 as big as you want to go? You do have more space available. If 13 cu.ft. is your limit, the CSS SDX15 would work well. The model is with one channel of the EP2500 (650 watts). Porting would be one 6 inch diameter tube 21.5 inches long. No high pass filter would be required.

SDX15.JPG
 

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Discussion Starter #14
Mike P.
I'll measure again to see exactly how much room I've got(absolute max), I'll post back tomorrow with the measurements, thanks again.
Mike
 

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Discussion Starter #15
OK, I did more measuring today, Looks like the most I can squeeze in there is ~21.5ft^3 ext volume. So I guess that would be ~18ft^3 int functional volume.

Which sub in that $300 range would work best with that volume and ~15hz tune port?

thanks again.
 

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Discussion Starter #17
funny you ask.
I meant per sub, now I'm wondering if i should build 1 box of ~23ft3, with one 600 dollar 18 and the ep2500 bridged?

what do you think?
 

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Kevin has the new 21" Mal-x coming out soon. That would be fun in a 20+ ft3. :bigsmile:

Matt
 

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Discussion Starter #20
I think I'll go with one FiQ18 in a ~23ft3 box with the ep2500 (bridged?).

Which speaker do I get (voicecoils, ohms, etc?)

other question is about acceptable box specs-(port air velocity, first resonance, ??)

any help much appreciated.
 
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