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Very interesting read Steve. Well done. I quite enjoyed it.

I do have to take a small exception to your three graphs in the original post, although I suppose you copied them from elsewhere and had no control.

The vertical scaling is quite inconsistent between the three graphs, and makes it difficult to draw meaningful conclusions......

brucek
 

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Re: LLT Explained

Very interesting read Steve. Well done. I quite enjoyed it.

I do have to take a small exception to your three graphs in the above post, although I suppose you copied them from elsewhere and had no control.

The vertical scaling is quite inconsistent between the three graphs, and makes it difficult to draw meaningful conclusions......
brucek

it would "seem" that the only one that is coupling to the room properly is the first example given in the 18" Avalanche...i wonder what the dimensions are for each room...:ponder:
 

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Re: LLT Explained

The guidelines/specific advice section is very helpful. Thanks for doing this writeup. I'm sure it took a good amount of time and effort to get everything worded the way you want and organized into a presentable fashion, but it's nice to have something comprehensive. Thanks again for the effort.:clap:

Hopefully this will save you from answering so many questions.:yawn: ;)
 

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Re: LLT Explained

Wow! Are you prepping for a presentation at AES this fall? Are you sure you should not have been a writer instead of what you are doing in life now? Excellent explanation. Very factual, scientific, and based upon repeatable results if the "formula" is followed. You should make up a general spreadsheet with different drivers, sonotube sizes, port lengths, and the various tuning frquencies that go along with the other factors as kind of like a general reference card of where to start when one wants to build one. How many times has the brotherhood put its arm around someone and gone through the WinISD ritual to come up with the same values we have come up with before. A little cheat sheet you could put out as a starting point for people thinking about build ing one of these might give them an idea of what they are getting into. Good work.

Chuck
 

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Re: LLT Explained

I do have to take a small exception to your three graphs in the above post, although I suppose you copied them from elsewhere and had no control.

The vertical scaling is quite inconsistent between the three graphs, and makes it difficult to draw meaningful conclusions......
Yeah, three different owners running their measurements in three different months. Not ideal, but just a very generic representation of what can be achieved at various tuning points with different drivers.

it would "seem" that the only one that is coupling to the room properly is the first example given in the 18" Avalanche
Well the coupling area with an LLT will begin around 25-30hz and extend down to just below the tune - below that, the 4th order rolloff comes into play and there will be a dropoff. Flat output definitely won't go on for ever. Considering the third sub's tuning is coming in around the high 16hz area I believe, the extension to ~13hz is pretty impressive. If you were to take a ported sub that measured very flat to 18hz anechoically, like an Axiom EP1500, you would not get such results without heavy EQ in room.

Hopefully this will save you from answering so many questions
HOPEFULLY :bigsmile:

Excellent explanation. Very factual, scientific, and based upon repeatable results if the "formula" is followed
Thanks. A logical and factual explanation of the real benefits was one of my top goals, as there are people with no clue as to how such a design really works saying things about it that are completely wrong and backwards - it's not a knock, but they just don't fully grasp the design intent. For people who have enough interest to want to understand why this design works and why it came about, hopefully this will shed some light.

A little cheat sheet you could put out as a starting point for people thinking about building one of these might give them an idea of what they are getting into
Yeah, I might just list my main designs for popular drivers so it could be a one stop source.
 

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Re: LLT Explained

Good thing this was made a sticky ;) It would be a shame to lose all of this easily read information.

My next but very distant project will be a ported Avalanche 15" sub. Whether or not it'll fit the LLT description by design is still up in the air. Haven't figured out where an LLT would fit in my room :neener:
 

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Re: LLT Explained

My next but very distant project will be a ported Avalanche 15" sub. Whether or not it'll fit the LLT description by design is still up in the air. Haven't figured out where an LLT would fit in my room
I don't know Ex? I'll be real surprised if you don't do another sealed.:bigsmile:

Nice writeup Steve, who could ever explain it better than you..and to think that's been there since 9/20! I've definitely been out of the loop lately.
 

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Re: LLT Explained

Yeah, another sealed is definitely my only option.My mom didn't like the idea of housing a water heater in the living room :( She just doesn't understand the sacrafices we need to make to join the brotherhood! My dad thought the sono was a cool idea though..

Once the Tumult gets fixed and I build another enclosure, unibox shows something in the neighborhood of 110db at 20hz and 100db at 10hz with just 450 watts of power to the Ava15 and 450 to the Tumult. That should hold me over for a while...afterwards is a well needed amp upgrade. With 450 watts each of these babies are just coasting along ;)
 

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Re: LLT Explained

My mom didn't like the idea of housing a water heater in the living room She just doesn't understand the sacrafices we need to make to join the brotherhood!
Reminds me of the Fresh Prince song, Parents Just Don't Understand :R So how many more years of school do you have before you can move out and go nuts?
 

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Re: LLT Explained

Reminds me of the Fresh Prince song, Parents Just Don't Understand :R So how many more years of school do you have before you can move out and go nuts?
Yeah, you gotta fight. For your right. To paaaaaaaaaaaaaaaaaar-tay. :paddle:
 

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Re: LLT Explained

Reminds me of the Fresh Prince song, Parents Just Don't Understand :R So how many more years of school do you have before you can move out and go nuts?
Yeah, I remember that song haha, great song.

Well, the mrs. graduates before me and wants me to move in but she graduates in may 07'...i'll have to worry about WAF in that situation :sad: and another sad things is I won't graduate for another few years because I switched from one major to another at a different school and lost LOTS of credits :( I could easily be on my way to graduation by now...but at my first school i didn't like the idea of sitting on my **** and maintaining a gpa of 3.7..wanted something a little more challenging :T boy did i get it.
 

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Re: LLT Explained

Wait a second, so if I understand this right, you haven't finished college, but you're married? :no: You're married but you live at your parents house? :no: Oh man.....oh man :sad2: Before you got the chance to be independent, you went and got married, so now you will transition from one form of control (parents) directly into another (wife), one that's supposed to last for the rest of your life, with no buffer inbetween. But hey man, different strokes for different folks, more power to you.
 

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Re: LLT Explained

Wait a second, so if I understand this right, you haven't finished college, but you're married? :no: You're married but you live at your parents house? :no: Oh man.....oh man :sad2: Before you got the chance to be independent, you went and got married, so now you will transition from one form of control (parents) directly into another (wife), one that's supposed to last for the rest of your life, with no buffer inbetween. But hey man, different strokes for different folks, more power to you.
hahaha, i guess i'll never enjoy that single life eh :joke: Thats the only thing I honestly feel like im missing out on...I've been there, done that. At this point I guess you're right, couldn't see myself without her though...its that nice spending time w/ her. Hope it stays this way :)

But man, LLT is going to be awesome, especially when I get a dedicated room that "I" and only "I" have control over ;) Whenever that may be.
 

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Re: LLT Explained

hi all

new here. Thanks for the write up, will have to read it another ten times yet tho!

Earlier read the saga that Exocer had with his subs, and got very confused every time Steve jumped in with hints about using an LLT!! For the life of me couldn't work it out, now I know.

Will continue browsing but this idea does appeal to me so in all likelihood - I'll be back (said in my best Arnie/terminator accent).

One quick question tho, in order 'to get around' the huge volume requirements, can some of the enclosure be the under floor space? ie some sort of opening into the cavity a la an IB type arrangement and using the space under the floor as a psuedo enclosure. I'd guess no, as in all likelihood it needs to be totally airtight, but thought I'd ask anyway, if only to straight away establish my credentials as 'the one who asks stupid questions' !

lots of love

terry
 

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Re: LLT Explained

Well volume is volume, so I don't see why it wouldn't work. The enclosure does have to be air tight though, aside from the port, otherwise the leaks will act like several ports, and that will throw off your design. Feel free to ask any questions along the way if you go forward :T
 

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Re: LLT Explained

thanks Steve

to be honest I think my suggestion/thought was a tad daft, there is no way even in my situation that it would be airtight. Forget it. Thanks for the response tho!!

Am busily printing off your writeup (much prefer to read it in my hands so to speak), to fit it on my page had to print it sideways??!!

May as well get this out of the way first up. I've got four peerless XLS drivers, unfortunately they are the 10 inch versions- seems the 12's are useful but what the hell can I do with these??

I hoped that your LLT's might prove useful in getting these things to work, but my little bit of mucking around with winisd (admittedly with little real understanding of the process) still seems to yield useless results.

I know there are two versions of the xls 10, mine is the 830452. I will stop now if you or someone else lets me know they are useless in this application, otherwise I will study your writeup and try and suss it out, maybe asking for a bit of advice along the way.(I don't want to just 'pick someones brains', I'd like to contribute a bit. You know, god helps those who helps themselves type of thing.) Needless to say I'm new to speaker design.

If it is not a straight 'forget it', then I'll start a new thread and see where we end up. Thanks a lot.

If it is a straight forget it in this application, maybe a bandpass? I only really want to do from 20 to 50 or 60 hz.

It'd nearly printed off!

lots of love

terry
 

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Re: LLT Explained

I haven't looked at the parameters for those specific drivers as of yet, but assuming they aren't really geared for deep low end sensitivity (I'd imagine that's a pretty safe assumption), I don't think LLT would be the best application. I'd consider a more traditional ported design - smaller, tuned higher, using a highpass. Can you post the paremeters here?
 
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