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Forum Home » Sound Reinforcement » LAB Subwoofer » My first Sub Design.

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My first Sub Design. [message #80905]

Thu, 13 October 2005 01:09

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
Messages: 822
Registered: March 2005
Location: Santa Rosa

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Finally popped my cherry.
Here's my First cab ever. God What hard work.

index.php/fa/2777/0/

index.php/fa/2777/0/

I'm Calling it the BS-212. Partly because BS can be interpreted as many different things. But It really stands for Bajor/Steckling.

I researched and designed the cab, (assisted by Harris Tech Bass Box Pro) around the Lab 12 Subwoofer. Jerry Steckling gave me some construction and configuration suggestions, and graciously provided the facilities to do the work in.

As far as I can tell I'm -4dB around 25Hz with roll off starting around 50Hz. Though I haven't gone outdoors with the TEF to see what's really happening.

I'm planning on using these for a bass rig, and possibly reference subs when playing with Some DAW mastering.

Just wanted to Share.

I will post all of the outdoor TEF sweeps once I get these out to the field with some test gear.

Cheers!!!

Antone-

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Re: My first Sub Design. [message #80907 is a reply to message #80905 ]

Thu, 13 October 2005 01:11

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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Heres a rear end shot

index.php/fa/2778/0/

index.php/fa/2778/0/

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LAB12 heat exchanger [message #80914 is a reply to message #80907 ]

Thu, 13 October 2005 01:50

Wayne Parham is currently offline

Wayne Parham
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Since you're using the LAB12, I encourage you to look at the work I've done on improving thermal performance.

Wayne Parham
π Speakers
PiSpeakers.com

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Re: LAB12 heat exchanger [message #80927 is a reply to message #80914 ]

Thu, 13 October 2005 06:06

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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Hmm Don't know if I want it sticking out in front of this cab with the Differential setup. I don't think I'd be able to get a grill cloth in front.

Is it just aluminum pipe with some heat sink compound attached to an aluminum plate? Would Copper pipe work well also?

Antone-

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Close TEF Measures [message #81120 is a reply to message #80905 ]

Thu, 13 October 2005 21:51

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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Here are some close measures I took of the driver an inch or so away overlayed with measures from in front of the port (Almost in).

index.php/fa/2786/0/

index.php/fa/2786/0/

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5 String Bass rig!!! [message #81265 is a reply to message #80905 ]

Fri, 14 October 2005 14:30

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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Wow these things are fun.
I felt sick to my stomach from sub bass for the first time playing a 20Hz Tone. I also experience the same voice modulation phenom' that Michael E. Was talking about experiencing with his dual 2245 CABS.

Here is a shot of the Boxes with my TL606's on top for mid bass to nice Breakup mode upper mid 80-3kHz. Its nice to finally have some authority in the sub range. I can really Rock the house with my LOW A string (maybe I should buy some of the .150 gauge strings and tune to low F# Muahh Hahhh Hahhh).

index.php/fa/2788/0/

index.php/fa/2788/0/

And its actually reasonably portable LFE for a bass rig if you got a big enough vehicle.

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Re: My first Sub Design. [message #81266 is a reply to message #80905 ]

Fri, 14 October 2005 14:39

Evan Kirkendall
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Registered: November 2004
Location: Abingdon, MD

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Sound guys are gonna hate you. Twisted Evil

Twisted Evil

Sound guy: "I can hear the damn band over your bass rig. Im clipping 2 JBL SRX725's with PLX2402's bridged trying to get to vocals on top."

Audience memeber: "My head feels like its gonna explode when you are playing!"

Have fun... Smile

Smile

Evan

HarfordSound
ATL Tour Blog

"This rig needs some finesse to get rid of the excessive spectral buildup." -Tom M.

Member of the Maryland EV QRx Mafia

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Re: My first Sub Design. [message #81293 is a reply to message #81266 ]

Fri, 14 October 2005 16:30

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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Awe Come on I'll just be able to compete with the Marshall Stack players. Only like 123dB at 27.5Hz with 1600Watts.

You know its actually amazing how intelligible everything is with these cabs since the Diff configuration cuts down on Harmonic distortion. I can really over hype the Sub Region but the vocals are still really intelligible.

Now its really a chore trying to fight for intelligibility over saturated guitar, especially when you can't convince some overzealous guitarist that its in everyones best interest for him to keep his stage levels down. Talk about spectral clutter.

I love the guitarists that like to play so loud that you don't need to add them to the mix and your standing 75' or more away from him at mix position (even better playing that loud in a little dive bar). "But dude I can't get my tone if I don't play like that." But dude your ears are probably so fried that you need to play it that loud to hear any tone.

I should just announce to the audience that I have come to make them sick.

Antone-

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Re: My first Sub Design. [message #81352 is a reply to message #80905 ]

Sat, 15 October 2005 00:51

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Actually, to be brutally honest, the LAB12s make a lousy direct-radiating pro subwoofer because they require a cab that is so big to get lots of low. You could have easily fit a pair of 15" in the same space, possibly even a pair of 18".

Wayne, have you measured the T/S parameters of the Lab12 with your heat exchanger contraption stuck up the Lab12's hole? Some important things, like Qes, could change. Loudspeaker motors are designed for a certain amount of flux saturation.

I've said and written things in the past that I wouldn't throw away in my own trash can for fear that you'd find them. My name is mud.

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Re: My first Sub Design. [message #81357 is a reply to message #81352 ]

Sat, 15 October 2005 02:29

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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Yes I could have used a couple of 15's Rory Or an 18. But my goal was extra LFE in a reasonably sized package.

Even So the only drivers that come anywhere close to the LF extension are TAD 1603's and 1801's But they cant handle the same amount of power and would require a cab of similar size. The TAD 18 would require ~10Cu' port not considered. A 4Lab cab would need to be 12cu' But I can split it into two 6cu' cabs making it much easier to move. I have a little lower Cut off and a bit more output (with about 8X the power as a trade off).

There are other more efficient drivers out there for anything above 30-40Hz range but the range where the labs win in efficiency below that range.

Even the Seismic does not have the same level of extension. In a not so optimally sized box for the Seismic (10Cu Ft.) Theoretically I can get 115dB @ 20Hz with 1000Watts Port tuned 25Hz. With the 4Labs In 12CuFt I can get 117.5dB @ 20Hz with 1000Watts Port tuned 22.13Hz.

If I push the Seismic's box up to 12cu' I can get 118.1dB @ 20Hz Port tuned to 23Hz. But again I dont want too have to move 1 12Cu' box for a bass rig I'd rather move 2 6cu' boxes. The seismic really wants a 2.3cu' box with a foot wide 61" long port tuning it to 44Hz ("High Fidelity Tuning").

Another Driver I was considering is the Sonicraft SC-12SC-.
I could have more low extension greater xmax but in a significantly larger cab with less power handling.

So the Lab 12 may not be much of a low to midbass motor but In the low 30's to twenties Watt For watt Is a much stronger subwoofer than a majority of other direct radiators available.

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Re: My first Sub Design. [message #81381 is a reply to message #80905 ]

Sat, 15 October 2005 09:12

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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.

[Updated on: Sat, 15 October 2005 09:13]

I've said and written things in the past that I wouldn't throw away in my own trash can for fear that you'd find them. My name is mud.

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Re: My first Sub Design. [message #81402 is a reply to message #81381 ]

Sat, 15 October 2005 12:58

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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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-

[Updated on: Sun, 16 October 2005 05:04]

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Successful gig. [message #81510 is a reply to message #80905 ]

Sun, 16 October 2005 14:12

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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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-

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Re: My first Sub Design. [message #81748 is a reply to message #81402 ]

Mon, 17 October 2005 18:46

Tim Duffin is currently offline

Tim Duffin
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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

www.spl-sound.com

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Done my homework. [message #81887 is a reply to message #81748 ]

Tue, 18 October 2005 12:50

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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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

[Updated on: Fri, 21 October 2005 01:58]

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Scary Bass, Good. [message #88130 is a reply to message #80905 ]

Wed, 16 November 2005 14:20

Antone Atmarama Bajor is currently offline

Antone Atmarama Bajor
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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-

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