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Old 21st October 2011, 08:49 PM   #1
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Default 18" LMS-Ultra

Running the simulations in 3 different software sources, I get an F3 of 45 for sealed 2.8 cubic foot boxes and F3 of 25 in a ported 5.3 cubic foot box.

I see so may guys running them in huge boxes sealed that would be a Q of .5x. Bigger than 5.3 in ported boxes would kill transient response wouldnt it?

Whats the big rave about these subs? Am I missing something?


What am I missing? Wouldnt 2 15" TC LMS-15 in ported 10 cubic foot boxes be a much better choice? Sealed they drop to 37hz Im not hating on the 18 just trying to understand the reasoning. two of the TC 15's even cost less. I'd rather have less cone weight and more drivers for power handling not to mention it beats the LMS ultra in extension out of the box. Lighter, deeper, more cone area, and cheaper.....
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Old 21st October 2011, 09:04 PM   #2
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What's an LMS-Ultra?
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Old 22nd October 2011, 01:09 AM   #3
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TC Sounds LMS Ultra 5400 18" DVC Subwoofer 293-666
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Old 22nd October 2011, 01:35 AM   #4
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I to would like to know
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Old 22nd October 2011, 04:25 AM   #5
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Originally Posted by mclsound View Post
I to would like to know

Just two days ago you started a thread that you were looking into TC sounds subs to compare to an Aura 18.

The post just before yours gave a link to the TC Sounds LMS-Ultra 5400.

Applogies if my partial naming of this 18" sub was incomplete. I dont have the ability to edit the original post at this point.
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Old 22nd October 2011, 08:21 AM   #6
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This the same Spin from vette forums?
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Old 22nd October 2011, 11:44 AM   #7
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Originally Posted by m R g S r View Post
This the same Spin from vette forums?
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Old 27th October 2011, 02:27 PM   #8
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Originally Posted by SpinMonster View Post
Running the simulations in 3 different software sources, I get an F3 of 45 for sealed 2.8 cubic foot boxes and F3 of 25 in a ported 5.3 cubic foot box.

I see so may guys running them in huge boxes sealed that would be a Q of .5x. Bigger than 5.3 in ported boxes would kill transient response wouldnt it?

Whats the big rave about these subs? Am I missing something?


What am I missing? Wouldnt 2 15" TC LMS-15 in ported 10 cubic foot boxes be a much better choice? Sealed they drop to 37hz Im not hating on the 18 just trying to understand the reasoning. two of the TC 15's even cost less. I'd rather have less cone weight and more drivers for power handling not to mention it beats the LMS ultra in extension out of the box. Lighter, deeper, more cone area, and cheaper.....
One would think 2-15,s is better than one 18 in ...lets say a 275 foot squared room.
But would the 18 be better if you seal it compared to the sealed 15's?
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Old 1st November 2011, 07:17 AM   #9
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Originally Posted by mclsound View Post
One would think 2-15,s is better than one 18 in ...lets say a 275 foot squared room.
But would the 18 be better if you seal it compared to the sealed 15's?
Here is a screen shot of 3 models:
Green line= ported LMSr 15 TC sounds 10 cubic feet 2 drivers
Red line= sealed LMSr 15 TC sounds 10 cubic feet 2 drvers
Yellow line= Sealed 18 Ultra 5 cubic feet .54 QTC

At no frequency from 15 to 100hz does the ported 15s not have greater output than either other model and at 20hz its +6db stronger for the ported 15s. Sealed the 2 15s beat the single 18 at every frequency.

Click the image to open in full size.


I would imagine that these builds with really huge sealed boxes have too low a Qtc. When you grossly oversize a vented alignment it kills transient response and produces one note bass (EBS), doesnt it?

In the case of ported vs sealed, the sealed subs have the greatest excursion at the tuning frequency while ported boxes tuned maximally flat have the best transient response and the cone's motion is at the minimum motion point. Wouldnt the use of a sub that has 6db more output at 20hz also have less distortion since its the minimum motion point with 1/4 of the power to make the same SPL? 2 15's have greater cone rating area which would be more eficient. I run each side (two 15's side) with a Peavey CS4080hz. Its a total of 8000 watts and I never have them bottom out. I tuned to 20hz. Even at 15hz its still more output.

Am I missing something? I feel its comparable since the two 15s cost a bit less than one of these 18's.

Last edited by SpinMonster; 1st November 2011 at 07:28 AM.
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Old 1st November 2011, 09:04 AM   #10
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That is what i figured.I would rather run 2 15/side than one 18.If I could afford the 18's I would but that is $4000+amp$$.That is 5ft3/15 which is a fair size if you were to run 4 of them(well actually,I still have 1 pair of CSS SDX15's.
Thanks Spin
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