| Alternate uses and modifications - first post ponderings . . . [message #321116] |
Fri, 09 May 2008 04:00  |
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I'm proud of that title, especially considering it's 3:30 in the morning, haha. Now, on to more serious discussions . . .
cliff notes question at the bottom
I worked as an assistant DJ for 5-6 years or so. Essentially, I was the pack-mule who carried all the heavy stuff and got to flip the lights on and off. I'm now planning on branching off and starting my own business in a co-op to my former employer. Being the (cheap) meddling kind of person that I am, I have to design and build the speakers myself (what self proclaimed pseudo-audiophile wouldn't?)
But first, a little background to make answering my question a bit easier. . .
Toward the end of my stint as glorified pack-mule I started working with a guy nearby who did live concert sound utilising an octo-set of LAB horns and a sextet of EV MTH-1 horns. Impressive sounding system to my ears. After that I attended a media institute and received my associates degree in Recording and Music Technologies. Since I was 13-14 (I'm 22 now) I've been playing in car and home audio, building and studying designs and drivers. More or less, I'm saying I've been around the block (albeit nowhere near as many times as most of you) so please do not feel the need to dumb things down for me, I'll figure them out.
Having used the LAB subs in the live sound rig I worked with, I'm impressed with the sound and output, and would like to replicate that performance on a smaller scale. Moving a 400 pound subwoofer by myself, often up and down steps does not make my back feel good. My question is, how hard would it be to modify the LAB sub to utilize a single driver per cabinet and hopefully reduce the weight.
Consider that this is a DJ application, so super high SPL is not necessary (but would be nice to have for extra large venues), so I believe a pair of single driver horns would be more than sufficient. I've also been reading the papers authored by W. Marshall Leach Jr. ( http://users.ece.gatech.edu/~mleach/papers/HornPaper/HornPap er.pdf) and John Sheerin (http://ldsg.snippets.org/HORNS/design.html) so I'm getting an idea what I'm getting into.
Cliff Notes Version
How hard would it be to modify a LABhorn to utilize a single driver to hopefully reduce size and weight (considering I need to keep the horn length about the same)
How well would this work in a horn if I decide to use a driver other than the Lab12 http://www.acoustic-visions.com/~acoustic/products/subwoofer _drivers/shivax/. I like this driver because of the super low Fs, and the fact that it employs an XBL^2 motor (which I love the sound of, I own a couple Adire Brahma 12" subwoofers)
I'm more or less trying to design a pair of single driver bass horns (30-250ish hz response) that are relatively lightweight (under 200 pounds if possible). I know it's a tall order, but I would really like to avoid using traditional baffle designs. Any suggestions would be greatly appreciated
(I hope this was understandable, I wanted to make it somewhat bearable to read while still touching on most points.)
Whoever said the pen is mightier than the sword has obviously never encountered automatic weapons - Gen. Douglas MacArthur
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| Re: Alternate uses and modifications - first post ponderings . . . [message #321195 is a reply to message #321116 ] |
Fri, 09 May 2008 11:57  |
 Mike {AB} Butler
Messages: 1686
Registered: April 2004
Location: Lynchburg, VA |
Has No Life |
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| Jared Scott wrote on Fri, 09 May 2008 05:00 |
My question is, how hard would it be to modify the LAB sub to utilize a single driver per cabinet and hopefully reduce the weight.
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Not possible, as changing the compliment of drivers, decreasing mouth size, and horn length would turn this box from a sub woofer into a woofer.. and probably would be very unpredictable how well it would work as well.
| Jared Scott wrote on Fri, 09 May 2008 05:00 |
Consider that this is a DJ application, so super high SPL is not necessary (but would be nice to have for extra large venues), so I believe a pair of single driver horns would be more than sufficient.
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If you are a DJ, you know already that there is never enough bass! You need MORE Headroom on bass notes, not Less!
| Jared Scott wrote on Fri, 09 May 2008 05:00 |
How well would this work in a horn if I decide to use a driver other than the Lab12?
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Different drivers require a different horn taper, throat, and displacement. Each horn is unique to the driver it was designed for.. to get best results.
| Jared Scott wrote on Fri, 09 May 2008 05:00 |
I'm more or less trying to design a pair of single driver bass horns (30-250ish hz response) that are relatively lightweight (under 200 pounds if possible). I know it's a tall order, but I would really like to avoid using traditional baffle designs. Any suggestions would be greatly appreciated
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Agree with the other posters, maybe a Fitzmaurice Tuba 36 or Titan 36 might help out.
Regards,
Mike Butler
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| Re: Alternate uses and modifications - first post ponderings . . . [message #321618 is a reply to message #321526 ] |
Sun, 11 May 2008 05:03 |
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I've pretty much settled on building a pair of LAB 12 horns for the big venues, but I'll be using a pair of Eminence Definimax 4018LF drivers seeing 6.8 cubic feet each tuned to 34 hz for the smaller venues.
Power for the LAB subs or the 18s will be provided by a QSC RMX-2450. The Lab subs will see about 950 watts per cabinet at ful power and the Definimax subs will see about 500 watts per channel.
Now, on to the mids/highs.
Whoever said the pen is mightier than the sword has obviously never encountered automatic weapons - Gen. Douglas MacArthur
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| Re: Alternate uses and modifications - first post ponderings . . . [message #321662 is a reply to message #321618 ] |
Sun, 11 May 2008 11:32 |
 Al Limberg
Messages: 1199
Registered: April 2004
Location: Saginaw, MI |
Has No Life |
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You might want to reconsider the 2450 on a pair of LabSubs. Remember that the actual impedance is very close to 6 ohms per cabinet when the acoustical impedance is included in your figuring. That drops you down in the 600-650 range per cab and that isn't going to cut it. Two 2450s bridged (one per LabSub) or two 1850HDs would be much more realistic.
?;o)
Al
Some people are like a Slinky.....not really good for anything, but you still can't help but smile when you see one tumble down the stairs.
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| Re: Alternate uses and modifications - first post ponderings . . . [message #321718 is a reply to message #321662 ] |
Sun, 11 May 2008 14:51 |
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Even so, with most of the venues I will be playing, considering the efficiency of this sub, 600 watts per will be plenty. I also have to take into consideration that there are many places around here with old wiring that honestly will be lucky to support that kind of current draw, much less any more.
The guy I work for just uses a pair of dual 15" MTX DJ speakers getting 450 watts per side, and that is sufficient for most places.
Besides, unless I messed up on my match, doesn't 2 6 ohm drivers wired parallel offer a 3 ohm load presented to the amp? I'm not wiring them series inside the cabinet because I don't plan on using them in an array any time soon, just by themselves.
Whoever said the pen is mightier than the sword has obviously never encountered automatic weapons - Gen. Douglas MacArthur
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| Re: Alternate uses and modifications - first post ponderings . . . [message #321726 is a reply to message #321718 ] |
Sun, 11 May 2008 15:13 |
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Ivan Beaver
Messages: 4189
Registered: January 2005
Location: Atlanta Ga area |
Has No Life |
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| Jared Scott wrote on Sun, 11 May 2008 15:51 |
Besides, unless I messed up on my match, doesn't 2 6 ohm drivers wired parallel offer a 3 ohm load presented to the amp? I'm not wiring them series inside the cabinet because I don't plan on using them in an array any time soon, just by themselves.
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Only if the drivers are mounted in the cabinet as was measured by Eminance.
When you load drivers in a horn the loading of the horn will actually raise the impedance seen by the amp. Some cabinets will actually double their driver impedance.
When you make a block of 4 the individual cabinet impedance will also change over a single cabinet, agian do to the TOTAL loading on the drivers.
Can I have some more talent in the monitors--PLEASE?
Ivan Beaver
dB Audio & Video Inc.
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