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-   -   Adire's XBL2 versus TC Sound's LMT (https://maxima.org/forums/audio-electronics/334784-adires-xbl2-versus-tc-sounds-lmt.html)

AscendantMax Dec 23, 2005 09:20 AM

Adire's XBL2 versus TC Sound's LMT
 
Haven't seen a technical thread in this forum in awhile...

Anyone know the pro and con's of each? I know both of these motor design tries to maintain very linear movement, even at high excursion levels. I personally have experience with the XBL2 with my Brahma, and it was a very clean sounding sub. No experience with LMT though (or how similar/different it is from my RL-p's TC9 design)

slickrick Dec 23, 2005 10:15 AM

http://forum.carstereos.org/t56398-d...hnologies.html

enjoy.

AscendantMax Dec 23, 2005 11:00 AM

damn, i actually read all of that...good read...

2 Da Max Dec 23, 2005 11:05 AM

I might be getting a RE SE or atlas 15

sorry Gordon but if i could get these subs for cheap no RL-P for me

slickrick Dec 23, 2005 11:14 AM

try researching.. atlas 15 will not be loud enough unless you put it in the rear deck which would be cumbersome at best. yeah gordon i read the thread recently, fun to read from educated people responding.

2 Da Max Dec 23, 2005 11:19 AM

dammit i want a sub!!!

what amp is good?

slickrick Dec 23, 2005 11:27 AM

w/e matches the sub you get...

2 Da Max Dec 23, 2005 11:54 AM

im buying your amp hoe

slickrick Dec 23, 2005 12:34 PM

no you will blow it up.

nismos14 Dec 23, 2005 02:41 PM

And I thought we discussed this already Avi. :repost:

AscendantMax Dec 23, 2005 05:31 PM

haha, avi just get a 15" MT and strap a pair of brutus to it. ;)

slickrick Dec 23, 2005 05:32 PM

no brutus.. SX 15 ported and call it a life.

2 Da Max Dec 23, 2005 10:54 PM

SX? dammit i like thE RE better.. how about a SX 10?

AscendantMax Dec 23, 2005 11:00 PM

only a 10? thought u were going for a little spl...

slickrick Dec 23, 2005 11:05 PM


Originally Posted by 2 Da Max
SX? dammit i like thE RE better.. how about a SX 10?

sx is made by RE...

2 Da Max Dec 23, 2005 11:05 PM

lol no im going to put a 15 in there, Right Rich

2 Da Max Dec 23, 2005 11:07 PM


Originally Posted by slickrick
sx is made by RE...


i meant SE

slickrick Dec 23, 2005 11:30 PM

what you're going to put in there is a quality system when you sell enough dope/ "loans" to afford one. ;)

Pearl96Max Dec 24, 2005 01:06 AM


Originally Posted by slickrick
what you're going to put in there is a quality system when you sell enough dope/ "loans" to afford one. ;)


Quality + Avi's systems = notgonnahappen.

nismos14 Dec 24, 2005 07:02 AM


Originally Posted by Pearl96Max
Quality + Avi's systems = notgonnahappen.


Sounds familiar :hide: not anymore ARCIFICATION COMING SOON!

Pearl96Max Dec 24, 2005 07:43 AM


Originally Posted by nismos14
Sounds familiar :hide: not anymore ARCIFICATION COMING SOON!


Ummm didnt get done til late yesterday, then still had things to do...

nismos14 Dec 24, 2005 08:22 AM


Originally Posted by Pearl96Max
Ummm didnt get done til late yesterday, then still had things to do...


Thats alright, just let me know when the best day will be next week. Otherwise I'll keep bugging you :naughty:

joebangaa Dec 25, 2005 09:39 PM

according to tc sounds, xbl^2 requires a very precisely set voicecoil. if the voicecoil is even slightly offset (as is usually the case in most drivers since they are glued by hand), it will result in the undesireable double-humped curve, not the seemingly flat BL curve that proprieters of the technology would have you believe

slickrick Dec 25, 2005 09:48 PM

so then wouldnt almost every xbl2 sub sound not that great because human craftsmanship isnt perfect.

joebangaa Dec 26, 2005 09:11 AM

that's just what i've been told. in fact i have a drive unit report with some graphs on a 10" brahma (from TC) showing this. if any of you want it PM me, but like i said it WAS from TC, a company that competes with others employing xbl^2...

AscendantMax Dec 26, 2005 03:51 PM

a section of Dan Wiggin's post:


LMT does flatten the BL curve. You also have massive power handling from the huge voice coil; it will take a ton of power to cook one!

However, it also carries with it several, IMHO fatal, drawbacks:

1. High moving mass. You start with an overhung, and add even more turns to it. And to get long stroke, you need a really long overhung voice coil to start with, which means the ends are so far out into the far fringe field you need a LOT of extra turns at the ends to add the proper amount of integration. And of course lots of turns means point 2 -

2. High inductance. Lots of turns = lots of inductance. This can be combated quite effectively with shorting rings; however, to lower the inductance linearly requires copper lining the gap, and that widens the gap. And you have to add a LOT of copper (in terms of thickness) to significantly affect inductance in the lower frequencies, meaning a really wide gap. Which brings us to point 3...

3. Low B field. Because you have extra layers in the voice coil, you need to widen the gap to account for the extra layers. This can double, or even triple the required width across the gap, meaning the flux in the gap will significantly decrease. Now, you get some total BL back from the extra turns, but it's usually better to get BL from B, not L. So you have to go to point 4,

4. Big motor size. To get lots of stroke in an overhung driver, you need a LOT of height. Imagine a 2" long voice coil with a 0.5" tall gap. Just at rest you must have 0.75" ((2-0.5)/2) of magnet stack, with ZERO motion. Now say you want 1" of backward stroke. That magnet stack is now 1.75" tall, minimum. Backplate thickness is added to it.

And it typically takes WIDE magnet stacks. Magnet force really goes as the area of the magnet, not the thickness. Since we're starting with really low B fields (see #3), we need a LOT of flux to make up to get anything decent in terms of B field in the gap. So we need to use bigger diameter magnets. Not only do we need a thick magnet stack, we need a wide magnet stack, which means a lot of extra weight, more volume occupied in your box, and limits how far down you can scale the design.

The most obvious example of this motor is the SoundSplinter RL-s design. A quick look at the T/S parameters will confirm that it has a VERY high moving mass (200+ grams for the voice coil alone, over 7 ounces!), and while it has a very long stroke (the voice coil is probably 3.5" long to reach the rated Xmax), it is VERY lossy; a BL of 13 N/A for a 3.5" long voice coil is extremely low (consider that the lowly Shiva Mark I, with a 1.5" long, 2" diameter voice coil - less than 30% of the copper - had a BL of 13 N/A).
So I guess each guy have their own opinion on each motor design.

slickrick Dec 26, 2005 04:12 PM

a bl of 13= not impressive for such a big sub.

AscendantMax Dec 26, 2005 04:39 PM


Originally Posted by slickrick
a bl of 13= not impressive for such a big sub.

:sprint:

the RL-p have a Bl of 21.9 for the 15" (dvc 4)


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