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Eminence Omega Pro 18's give you 25 Hz extension but you have to build exactly the right box, with the tuning actually at the resonant frequency to control the driver's tendency to overexcursion at the highest drive levels. The thing is, the Lab12s make such lousy direct-firing pro subs because they are, by themselves, woefully inefficient. They follow a model similar to today's hi-fi subwoofers where they use a really heavy cone and a really heavy voice coil and a long-throw suspension that has a lot of damping in it. They work well in the horn because the horn is hyper-optimized to get lots and lots of output from them, because they are strong drivers. It takes a large amount of pressure to counteract the motor's action. But efficiency is the key for a direct-radiating box. With both those drivers, you're probably only getting a net 91dB 1w/1m sensitivity. With the Kilomax 18, you would be getting 98dB 1w/1m sensitivity with higher power handling as well. And for a pair of 12's, that is not a reasonably sized package. Boxes look well-made, though.

[Antone Atmarama Bajor]

     The kilomax 18.  Models really Hot at 30Hz and 117.4dB at 20Hz  1000 Watts in a 16Cuft' Cab.  Not very linear in its band pass though very bumpy.  And the Cone is about 6mm past xmax @ 38Hz.

    That seems to be a major problem with most of the drivers I've been modeling.  They all look good initially until you look at the cone displacement they over excurd within their rated power bandwidth.   This is not true of the LAB12 I can put 1600Watts into the 4 of them and never exceed XMAX until I hit about 18Hz.  I'm not using them bellow 20 So I should be doing very well.

    I personally think that there needs to be disclaimers on Cabs and drivers saying  Cone Excursion Will be linear across X-Powerbandwidth.
Power bandwidth will be reduced above X-Watts RMS.

    I think that is the big lie in a lot of driver specs.  I was really irritated when my EVM15-B's Voice Coils started smacking the keeper plate driven at RMS.  Now I have them Crossed over around 80Hz and they are very happy with me.

    I would never try to use these boxes for a large PA but I think for a smaller club these things will really kick ass and the fidelity is very good.  By the way Two Boxes are 93.4dB Not exceptionally efficient but from the 40-150Hz Range I can put out about 125dB.  Great for onstage bass, studios etc.  But then I can use my BT7's for some of that too but I don't wanna lug em around.

    I'm glad you like the cab build though.  That was some hard work my hands still hurt.  Since it was a proto I used 3/4 Marine ply instead of some nice 13ply birch.

    Anyhow I will hopefully run some good outdoor measures on them soon.

Antone-  

   

[Antone Atmarama Bajor]

     I just took my BS-212's out on a gig.  The sax player and Violinist officially Hate them.  They didn't like being rumbled by the extra LF they were standing only 6' away.  I personally enjoyed the Organ Massage.  

    I don't think I've ever played with so much fundamental except when I played through My BT7's.  Now our band leader can stop complaining about not being able to feel my bass the way he wants.

Antone-  

[Tim Duffin]

In that case---"not enough xmax at 20Hz" a car audio driver would win out over pretty much all pro audio drivers, but sacrifice upper bass performance and efficiency.  Just for fun, have a look at Massive audio's DMX stage 2 12" driver.  At  www.massiveaudio.com
I think that for your application, even the lab12 isnt quite good enough.

T

[Antone Atmarama Bajor]

The Lab 12 is basically a "car subwoofer".

    The Massive Audio Competition and Reference subs are more than half the sensitivity of the LAB and and needs 1 Cu ft. larger optimized cabinet than 1 lab sub in an optimized cab.

    The 4 Voice Coil Monstrosity doesn't have close to the output of 1 LAB 12 At 20Hz both in optimized cabs Even with 2500 Watts behind it.  And what is the Street price of a DMX12????  Looks like a waste of money to me( well I guess the guys who buy them are only interested in a wicked 808 Kick drum sound).

    I wonder how much better the chrome plating on the Subwoofer Makes them sound!!!  I bet if you put some diamonds and gold on them The laws of physics would be circumvented and Bass reproduction would be increased to imesurable numbers.

    I think too many people are biased by brands that they have taken a liking to.
   
    The Lab 12 was not my first choice of drivers but the more I've modeled and compared the more I find it to be a superior motor down below 40Hz.  My original choice was the Sonicraft
SC12 NRT.  Another Fun one would be an NHT 1259 but Its sensitivity isn't very good, I don't really want to built 20 and 40 Cu' Optimized cabs for four of these things.  And the Lab is much friendlier on the wallet for its performance.

    If someone can actually find me a better performing woofer than the lab in the 30Hz and bellow range I want it!!!  I'm serious!    

Antone

[Antone Atmarama Bajor]

     Hey I just discovered a good LF Rich movie that will push the lower limits of ones subs.  The Atomic Bomb Movie Trinity and Beyond (Narrated by William Shatner).  I haven't gone through the whole film yet but the first Atomic blast from the Trinity test has a really nice percussive Shock wave that really gives you that sick to your stomach feeling!  Video quality is not very special but it has a really nice soundtrack.  

    I'm doubting that this is the original recorded sound from the military test film.  They probably sexed it up a bit but its pretty freaky.

    Do any of you have any suggestions of source material with significant sub bass down to the 20's.  I know some of the Standards are movies like Pearl (Necklace) Harbor, Jurassic Park and some silly U boat movie.  How about some music that has some actual recorded sub bass.

Antone-

[Ivan Beaver]

The Incredibles has some pretty heavy stuff at 10-15Hz!

Spiderman also has some great stuff.

[MARK PAVLETICH]

Let me get this right........You want a 25Hz extension box on bass guitar. What for ? The only time there is likely to be any energy in that frequency is when you thump the bass guitar with your fist.With a rig like this in any room short of Madison Square Gardens, that will happen just before the soundman or other band members thump you with theirs!!!!!!

[Dave Rickard]

MARK PAVLETICH wrote on Sun, 04 December 2005 21:00

Let me get this right........You want a 25Hz extension box on bass guitar. What for ?

So you can detune your low B down to an even low(er) G!  

(Great for the bluegrass banjo tunes in G)

Not seriously,
Dave

[[x]]

I agree. For lots of sub discussion pertaining to home theater, go here: http://www.hometheaterforum.com.

But for subwoofer discussion pertaining to pro audio apps, I recommend this page: http://srforums.prosoundweb.com/index.php/f/3/4508/?SQ=30901 625415114ecdaafee31982cd98e

Honestly, pro audio guys aren't concerned with 25 Hz and below unless they can get a lot of it loudly, efficiently, and cheaply. Which is almost impossible to do without big bass-horn arrays.