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Discussion Starter · #1 ·
Hey everyone,

I've recently acquired a brand new Aura MR-18.4 sub and have decided to tackle an LLT. I've currently got two TC Sounds Epic 8's handling everything from 50 to ~22Hz but I'm missing that last octave. I plan on powering this with either a bridged EP2000 or 4000. I read the LLT Explained thread and everything makes perfect sense to me so my plan was to slap this in 425 liters (15 cuft) net and tune it to 14.5 Hz or so.

I've built many subwoofers for the last 10 years but this is my first LLT. I figured I'd share the models to see if anyone has anymore insight on what I may be missing if anything.

Measured driver T/S specs:

Fs: 21.53 Hz
Re: 3.382 ohms
Qt: .492
Qe: .593
Qm: 2.874
Le (1k): 1.707 mH
Mms: 419.5 g
Vas: 8.966 cuft (253.9 lt)
SPL: 88.2 dB 1w/1m
Xmax: 31.75mm
Effective piston diameter: 15.25" (SD: 1178 cm^2)

Modeled Enclosure specs:

Total volume: 15.01 cuft (425.1 lt)
After port/driver/bracing displacement: 13.74 cuft (389.1 lt)
Port: 8" inner diameter, 40" length - Tuned at 14.77 Hz

Overall external modeled dimensions as per my requirements:

55" tall, 36" wide, 18" deep, bottom fired port on 8" 'legs' with the woofer mounted on the lower right hand side of the cabinet - similar to Ricci's RE XXX18 LLT box only not quite as big and without a power port.

Response with 500 watts:


Cone excursion with 500 watts:


I used 500 watts as the power input due to the fact that I won't be cranking this to reference levels. I modeled it with 800 watts and the excursion is exceeded at 11 Hz but not quite to Xmech.

The room itself is ~14'x16' open to a small kitchen and dining room and this will hopefully be next to the seating position so room nulls shouldn't be much of an issue. Sorry for the novel but I'm trying to eliminate a lot of the questions ahead of time.

Any thoughts?
 

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Looks like you did your homework: only thing you might be aware of is being able to localize the sub from the seating position (my Mal-X LLT is like that). I will say that I used my bfd 1124 to roll off freq above 50hz and up while my other subs get the full <100hz sub output (they begin to roll off around 50hz). Seems to have helped reduce localization.

Good stuff :T
 

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Discussion Starter · #3 ·
Thanks Glen,

I have thought about that issue and I'll probably have this crossed relatively low, around 40 or so. Possibly lower. I'll have to experiment a little to see which sounds the best. I don't have too many placement options where I am currently.
 

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Discussion Starter · #4 ·
Decided to post a couple pics of the sub. I'm not sure when the build will begin but it will definately happen. I will keep the thread up to date as things proceed.

For your viewing pleasure:





Thats an 11 lb Aura RPM2300 Stage 2 car amp next to it and the CD is for scale. Even with its neo motor it still weighs a hefty 44 lbs!
 

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Ive been modeling this beast as well. Cant wrap my head around the enormaty of the box(es).
 

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Discussion Starter · #6 ·
Ive been modeling this beast as well. Cant wrap my head around the enormaty of the box(es).
Thats what I initially though as well, but after seeing some other LLT designs around here, this is not too hateful. At only ~17ish cubic feet is pretty small considering.

FYI, the TS parameters in my first post are from my woofer if you want to use those for modeling purposes. They don't differ too much from the manufactures specs though.
 

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Yours is pretty close to spec. Why cant i find much about this driver? It sounds like a monster. I might score a pair soon but its hard to even find any subjective opinion on it.
 

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Discussion Starter · #8 ·
I've had a hard time finding anything as well. My only guess is that they weren't very popular for a few reasons, mainly price and there really weren't many Aura dealers. These models, including that amp in the pics haven't been manufactured since probably 2003. I can't even find any third party pics. Madisound still sells the anodized version and from what I can tell they are exactly the same drivers with different paint jobs. From what I can find, these are some of the best drivers ever produced.
 

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Sounds about right. Definately would like to try them out. No sense building something ill ever want to upgrade, right? Lol.
 

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The reason you hear very little about them is cost,
They're in the same price range as an LMS ultra in most cases.
Most people won't take the risk for that coin.

These are very high quality drivers, Most of the Aura Products tend to be.
 
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