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[Silas Pradetto]

Josh Billings wrote on Sun, 29 June 2008 06:05

+1 on 4. I can't imagine what 8 sound like. I do dance music and feel comfortable doing quite big shows with 4 LABs. Granted this is without DJs clipping the crap out of the mixer, but that's another story. I started with 2 but 4 is amazing and when you juse use 2 together you won't understand what the big deal is. -Josh Billings

I just finished another four, but I could only test a block of 6 because I'm waiting for a replacement woofer so I can use the last 2.

Let me mention...with 2000 watts per LAB, in a block of 6, it's hilariously amazing. Will report back with some numbers on 8 soon.

[danfowler]

From the WAY-BACK-MACHINE. I don't post that often anymore, despite my best efforts, too busy with shows.

Tim is correct, research befo' yo ax!
Just an additional keystroke or 2...............not hard really.

I'm 8 hrs. North of Atlanta (Sanford, NC)and I've built 16 of them there LAB 12's.
Very cool on an outdoor show:
Lay a blanket down in front of the sub array, use a oscillator and tune to the reso freq. and watch the blanket "levitate" off the gound. Can't find pics or vid of that (must be on the work computer) but it's seismic. I lost a hard drive a while back and that may be gone forever.

16 of these working in a single octave (30 to 60) work VERY WELL under my Line Array, driven by an aux. I just run them thru my Protea, hi and low pass them and delay the subs as required. They all power with Crest 9001's, 2 per channel.

I build all mine with 13 ply (18mm) Russian, 9 ply (12mm) on the module, a 3 hp router and a 10" table saw (Unisaw and Biesemeyer fence ,5 hp). Make no mistake, you need horsepower to work birch.
There are no "tricky" cuts on this design. Any rudimentary reading about woodworking at a LIBRARY (how f^&*ing old school!) will arm you with the knowledge of jig making to pull this off.
Really, I use a minimum number of jigs on this project. The one tool I really use is an fence angle-cutter from Woodworker's Supply. Love that thing.

Unfortunately, this project is WORK!!!! A lot of it.
80 hrs. is what it takes me to build 4 Labs. I AM a skilled woodworker (meaning all my fingers are still here) and I've built furniture in my college days, but this project needs just CABINET MAKING skills.
There are no "tricky" joints. Butt joints are all that is required. DO use screws (not staples) and Peter Sylvester's design is the one I went with since it is transportable.

You DO have to be able to perform precise, repeatable cuts on the tablesaw.
That's where the Biesemeyer Fence comes in.
If you've never heard of one, hmmmmmmmmmmm.....................
this may not be a good first speaker project for you.

My biggest problem on the whole project was speaker sealing. Air was leaking thru the stock gasket's screw notches. Just replace them with a solid one and use HD speaker clamps. Makes driver changes a 5 minute affair.

The hardest part is the module. Since they have to be made as a sub-assembly, get some 1/2" and build one. If you can't get that part square and tight, forget it, go to plan "B". Call in a cabinet maker.
Of course, that will blow the budget and your $700.00 killer sub just went to $1,500.00 plus. At that point, you should just consider buying some BassMaxx's.

Truth is, take a  d-e-e-p  breath, exhale, and think.
Am I a "gearhead", do I know HOW to use wood working tools well? Do I have the tenacity to complete this project? Have you built speakers before? Are you as hardheaded as the rest of us sawdust heads?
Are you willing to get paid NOTHING for your time and energy?

AND, lastly, do you have lo-mids and tops that will keep up with this design? That is the acid test.
If you survive the acid bath, fire up your saw!

later,
Dan 0;)


 

[Silas Pradetto]

You'd be delaying the tops, not the subs. The subs have a built in delay of about 10ms.

[Dave Junius]

Thanks for the info Dan,
I agree, I do think that the biggest concern is making repeatable cuts. I do not have a Biesemeyer Fence, I wish I did as they are nice. I have thought of getting one though, just keep putting it off for other stuff. I have however made a few cabinets a few years back and they came out sweet. Oak ply sides with solid oak faces, full length drawer slides and hidden hinges on the doors, then we made a custom top with a sheet of laminate on MDF with an oak edge. I have also made both of my cable trunks from birch, but that wasn't no 3/4. Anyhow, I've got the skills and I know I have the time and patience. Plus, like I mentioned in a previous post, our custom cabinet shop at my day job has volunteered to make the cuts for me. I need to take some pics of their work, it just comes out amazing. I know they have a Unisaw with a very nice feed table, big. They also said they could hook me up with a discount on the wood as they get a better price then I would as a guy off the street buying a few sheets.

As far as my tops keeping up, I have 4 Yorkie U15's now. Maybe someone else might give a better answer to that guestion. But I do remember a while back, I mean a long while. Someone had mentioned that they would be a good match, but I don't know for sure. I think I will start with 4, then see what happens. If I do start to get some bigger shows, then I'll build more and get new tops, but I will wait til that happens. I am getting myself all motivated and have been sitting here on the computer for hours trying to read all I can so I can make the best choices when it comes to building and using them. I have been interested in them for years, just never got motivated enough to do something about it. Thanks for all the info. And I am truly interested to try/see the blanket levitation.

Dave

[The Guy]

I've got 12 of them, all built by me.  +1 for everything danfowler has said.  No trickery here, just the right tools, accuracy, and time are all that are required.  Don't chintz out and build them with CDX plywood from home depot, or try and cut them with your FIRESTORM brand table saw.  They take a lot of time.  

The other thing, they are VERY big.  They look big on paper, and they're gargantuan in real life.  They don't need a ton of power, but you pay the price in cabinet volume! TANSTAAFL.  

-JB

Oh, and forget about U15's keeping up with 4 LAB subs.  

[danfowler]

True Silas, I wrote that backwards.
Need to delay the tops/not the subs. Mine delay about 22ms due to some other latency issues that the new Lake 412 should clear up when it gets here. The PA sounds best at that delay outdoors.

The U15's have been said to be an excellent hi-pack to the Lab12 with output to match and superior clarity. There has been discussion on here about the hi-pack out running the lo-mid ability on that speaker (hence the 215 I suppose).

When these 1232's are all gone, I'll use U215's over Lab12's for my "C" rig.

All depends on the program material. music playback should be fine with the U15. With live rock, they may be deficient for vocals and drum voices. All depends on the volume.

Sounds like the woodwork portion is no problem for you. Take advantage of the custom cabinet situation. You won't regret that.

If you get creative and crafty, you can get 1 LAB from 2.5 sheets of 4'x8'. My cost has risen to about $70.00 /sht. of Russian cross sanded 4'x8' in 22 sheet bundles.
22 sheets will build 8 Labs (if you don't screw up any cuts).
Post pics of your work. Sounds like you're on your way.

Dan 0;)

[Jeff Babcock]

Have you got a means of transporting a big block of Labs?  You'll need a good sized trailer at the least.  Your 4 U15's will look puny next to them.  I would expect you would need closer to 6-8 U15's to keep up with a center clustered block of 4 labs.  And if they aren't clustered in that block of 4 the results will not be nearly as good.  That can be very limiting if you are doing smaller gigs without good placement options.

Honestly unless your current 4 U15's are not giving you the sort of volume you need for your gigs and you intend to get more or better tops, I think Labs may be overkill here.  There are tons of other more portable horn subs out there that don't cost much more than the cost of materials for the lab by the time you buy birch, glue, screws, handles, casters, connectors, drivers, etc. Not to mention the likely 80 hrs of labor to build 4.....

The lab is an extremely powerful sub, just IMHO more geared to bigger dogs and bigger shows.  For a portable rig, there are other solutions that make more sense.

Your call.... just be warned of what you are getting into here.  I considered them at one point but when I weighed the options I couldn't justify them as a practical solution for my needs.

[Dave Junius]

Thanks for all the info.
I didn't realize that they would outrun my U15's that bad. However I am considering a new rig for the outdoor stuff (that I haven't had much of lately) and the larger indoor stuff. I guess I better start researching what WILL keep up with the labs before I commence the sawdust making.

And hey, anybody in the Tampa area have any labs, I'll be down that way around the 22nd of Sept?

Thanks again,
David

[Silas Pradetto]

My line array outruns 4 LAB subs, and only TWO Community TFR64s speakers will outrun 4 LAB subs. So you're looking at needing a speaker that will do 140dB continuous, not peak, at 1m to keep up with 4 LAB subs.

[Karl Bruhn]

I run 4 labs under 4 U15s. The ideal match seems to be 2 U15s for each lab which is my most used configuration. Overkill? Yes, but I'm working towards a line array.

I was unsure about the lab due to it's massive size. So I made some mods to Peter Sylvester's version 2 design by shaving off the front 5 1/2 inches right up to the first bend. All internal dimensions are unaltered. Five and a half inches doesn't seem like a lot, but the box seems much more manageable to move around and fits into tighter spaces. No regrets on choosing labs and wouldn't trade them for any other box. All glue is West epoxy. All surfaces are coated making them entirely waterproof. West powdered graphite was added to the exterior coating creating the black color. A word about glue. West epoxy used properly (including the filler additives) makes an indestructible joint allowing use of butt joints. I mix two small batches at a time, one straight with no filler additive and one with filler. First coat with the straight mix. This will be absorbed deep into the wood making the joint much stronger. Then use the mix cut with filler for strength at the joint. I did some tests using butt joints, 6 inch squares, with West and Gorilla glue. The gorilla glue failed easily right at the joint by stepping on it. I had to use a sledge hammer to break the West pieces apart and it did not fail at the joint. Instead, the break occurred half way through the ply. The downside is it's messy to work with.