LLT Explained - Discussion Thread - Home Theater Forum and Systems - HomeTheaterShack.com

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post #1 of 191 Old 09-19-06, 11:00 PM Thread Starter
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LLT Explained - Discussion Thread

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post #2 of 191 Old 09-20-06, 03:08 PM
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LLT Explained - Discussion Thread

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......

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post #3 of 191 Old 09-20-06, 04:24 PM
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Re: LLT Explained

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brucek wrote: View Post
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...

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post #4 of 191 Old 09-20-06, 06:07 PM
 
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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.

Hopefully this will save you from answering so many questions.
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post #5 of 191 Old 09-20-06, 07:31 PM
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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.

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post #6 of 191 Old 09-20-06, 08:04 PM
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Re: LLT Explained

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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.

Quote:
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.

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Hopefully this will save you from answering so many questions
HOPEFULLY

Quote:
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.

Quote:
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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post #7 of 191 Old 09-20-06, 09:45 PM
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Re: LLT Explained

Excellent write-up Steve!
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post #8 of 191 Old 09-21-06, 03:05 PM
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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

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post #9 of 191 Old 10-27-06, 05:32 PM
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Re: LLT Explained

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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.

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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post #10 of 191 Old 11-01-06, 02:35 PM
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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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