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Old 8th July 2002, 07:00 AM   #11
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Oh BTW thanks pinkmouse, haldor, and Brett for your great starters! I was very very surprised to see the experts at LAB recommending a 12" driver instead of a 15 or even 18 for lowest frequency response with best power. Also, I did a search for "Fane" on the web plus a few other variables, and got a lot more resources for design and building than I was finding previously.
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Old 8th July 2002, 04:51 PM   #12
haldor is offline haldor  United States
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Hi poorbutproud,

I know what you mean about the 12" drivers for the LAB sub. That's horn design for you, sort of a "everything you know is wrong" experiance for me. I trust Tom Danly knows what he is talking about (he is the chief designer for ServoDrive and they make the best subs on the planet). If you are talking about a ported box (or direct radiator) then the bigger the better, but a horn is very different. Just like a 2" horn mid/tweater will crank out an amazing amount of inband sound, while a 2" direct speaker would be barely audible.

Working from memory the LAB has usable output down to around 30 Hz, which is plenty low enough for live sound reinforcement. I use the 30 Hz high pass filter in my sub amp to prevent shreading the driver cones when the kick drum mic gets bumped or dropped.

Phil
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Old 9th July 2002, 05:29 AM   #13
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I second that, The bigger the better in your situation. A 12" would be flopping all over the place.

Poor? Go with Eminence. They have a few 18" models worth buying from $75 (yes, I said worth buying) to about 200. I would get the Sigma model. I think partsexpress has it for 160 ish. Put that In a 5 or 6 (maybe smaller) cubic foot box (for god's sake use plywood, not mdf!!!!) and brace the hell out of it. As far as amps go, ask somebody else.

Leave the top or a side removable and you could sleep in it.

If you get the $75 dollar model, do stereo subs!!!!
here is link$75 Eminence CAST FRAME!!
-andy
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Old 9th July 2002, 04:36 PM   #14
haldor is offline haldor  United States
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Quote:
Originally posted by bostarob
I second that, The bigger the better in your situation. A 12" would be flopping all over the place. -andy
Hi bostarob,

If you were talking about the typical HT sealed or vented 12" sub I would agree with you but you really should to take a look at what the LABHORN project is about before making statements like that.

http://www.prosoundweb.com/community/forum.php?board=3

The LABHORN is an very serious PRO subwoofer being hosted as a DIY project on the Live Audio Board. The principle designer is Thomas Danley of Servo Drive (this guy is the preeminent sub designer on the planet, if you haven't heard of Danley or Servo Drive then you need to educate yourself on what is happening in subwoofer technology), take a look at http://www.servodrive.com/servo/bt7.shtml if you want to see something else that Danley has designed.

Eminence has developed a custom 12" driver for use in this project called the LAB12, here is a picture of the driver
http://www.prosoundweb.com/lsp/customdriver1.jpeg.

Each sub uses a pair of these drivers. A pair of these 12" drivers will push more air than any 18" and do it with less distortion and cone breakup (much faster bass too).

4 of these subs (they are designed to be used in groups of 4) will deliver 147 dB @ 1 Meter from 28 Hz to 100 Hz and require 1/4 the power that direct radiating subs would require to get the same SPL). Flopping is not a term I would use to descibe this subwoofer. Bass that will pin you to the back wall of the arena is more like it. If you were to buy subs like the Labhorn from a commercial vendor they would probably set you back around $3K to $4K each.

Phil
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Old 9th July 2002, 07:00 PM   #15
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Well said Phil. You saved me typing out basically the same thing.

It seems some people just don't get how superior horns are in this sort of application, and just how different they are from DR's. But once you've experienced it, it's not soon forgotten. The generousity of Tom and Mark in doing this project at all is amazing.

I'm building a pair of LABs for my living room: EQ'd flat to 20Hz and placed as per Mark's suggestions, I don't think I'll need to upgrade again for a while. Flat against the rear walls, and painted the same semi-gloss white, they'll hardly take up any room and blend in well.

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Old 13th July 2002, 06:27 AM   #16
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Well, I guess I am a big dummy. With number as impressive as that, I will need to look into those horns.

But, this is a budget project.
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Old 13th July 2002, 04:51 PM   #17
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Hi Poorbutproud,

I know I haven't been an active participant in this thread, and all that have responded have done a good job. I just wanted to suggest a link with a lot of good information for the beginning pro.

http://www.jblpro.com/pages/tech_lib.htm

Good Luck,
Rodd Yamashita
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Old 13th July 2002, 05:35 PM   #18
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Quote:
Originally posted by bostarob
Well, I guess I am a big dummy. With number as impressive as that, I will need to look into those horns.

But, this is a budget project.
The projected sales price of the LAB drivers is between $US150-250. Numbers aren't settled yet as they aren't in-store as I type, but they will be within the next month.

For a pair of LABs (4 drivers), you would only need about 6 sheets of 2400mm x 1200mm (8' x 4') of quality ply per enclosure. If you are able to DIY, then even at max price the project comes in under poorbutproud's budget.

Mark Seaton has also suggested the Adire DPL12 as a substitute for deeper bass, lower peak SPL applications. Read all about it here
http://www.prosoundweb.com/community...rd=3&id=144164

The 186 horns from speakerplans would cost similar money to the LABs, for 4 enclosures. They are smaller, so are easier to move, depending on what size vehicle you have. If you have a truck, the LABs may even be better in some ways as they are designed to fit within standard truck pack dimensions.

Cheers
Brett
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Old 15th July 2002, 07:28 AM   #19
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Where can one learn about horn theory and design?

I apologize for previously being too hasty in my relpies...

Those LAB drivers look very expensive (impressive!)

Why foam surrounds!? http://www.prosoundweb.com/lsp/customdriver2.jpeg]Pic II[/URL] Eminence is priced well, but I couldn't imagine a speaker like that selling for much under $300. Wouldn't it be cheaper to build the 186 with an 18"?

Poor also stated that he wants one enclosure. I don't know if that statement still stands.
-andy
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Old 18th July 2002, 01:58 AM   #20
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Excellent responses, all.

I am definitely willing to build two enclosures, I had just *assumed* (ha, ha) that I didn't need to do so for small venues.

My rationale was that a single sub would be sufficient for driving my volume until I realized a need for additional reinforcement above my SRM450 pair. This is especially true in my opinion, because the lower range is much less directional (depending where you cut it). I guess I could budget up to a $400 setup for two drivers, a crossover and an amp. Forget about the plywood/finishing cost, it's free to me

Yes, the specs on the LAB project are awesome.
I see Eminence speakers for it are shipping now at +/- $150 for the initial shipment. If I can find an amp which matches them (totally clueless there at the moment, need to read more) and a crossover system (maybe I build my own bandpass circuit eh?)
then I'll be set!

For others who are curious like me, I found this for different eclosure shapes:

http://www-user.uni-bremen.de/~carni...hornfolds.html

BTW I checked the prices on the two ServoDrive lines, being curious about the mechanical nature of their amplification... whoohoo!! that stuff is for "stadium." I'll be back to them *after* I get a recording contract! heh.

Anyone who can tell me just how to match amplifiers to speakers based on specs, I'd appreciate it.

thanks loads, poorbutproud
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