FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Snapped a few photos tonight after installing the port walls, I very much feel like an alternate solution for handles is in order.

Photo 2013-02-03 11 29 45 PM.jpgPhoto 2013-02-03 11 29 56 PM.jpgPhoto 2013-02-03 11 30 09 PM.jpg

So far that extends 1" into the port, still needs to be capped off with either 1/2" or 3/4" ply.
 

Art Welter

Senior
Jan 11, 2011
832
19
18
Florida
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Even if the cap uses a rounded 1/2" piece that looks like a fairly big obstruction.
Mounting the handle above the port would be a better placement, but you knew that already.
Fortunately, patching holes is not very difficult ;^).
 
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Fired the cab up tonight, few finishing touches left to do (attach grill, decide what to cover the primer with, etc). Initial impressions are good, tested with an XTi4K, need a bigger amp.

Photo 2013-02-14 2 24 29 AM.jpg
 

Silas Pradetto

Graduate Student
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Fired the cab up tonight, few finishing touches left to do (attach grill, decide what to cover the primer with, etc). Initial impressions are good, tested with an XTi4K, need a bigger amp.

View attachment 6043

I've found that the Xti series is positively awful for subs, especially for drivers with loose suspensions such as the LAB12. Running LAB subs with an XTi 4000 and switching to an Itech 4000 yielded at least a 10dB increase in output...and that's way more than the dB increase from the extra power.

The class D/I amps have feedback that controls the cone way better. I recommend you get one and try it out for yourself.
 
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

I've had good luck driving 2-4 728s off of an XTi4K for gigs up to a few hundred people in the past, but that could just be a matter of cone area making up for less than optimal power. In this case, I found that just as the Lab 12s were really coming alive, the XTi was running out of gas.

We've got some Macrotechs laying around the shop, but they typically go out with the 728s for large jobs. Trying to find a good deal on some IT4Ks, or I might just bite the bullet and find some Crest CAs and deal with the weight.
 

Silas Pradetto

Graduate Student
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

I've had good luck driving 2-4 728s off of an XTi4K for gigs up to a few hundred people in the past, but that could just be a matter of cone area making up for less than optimal power. In this case, I found that just as the Lab 12s were really coming alive, the XTi was running out of gas.

We've got some Macrotechs laying around the shop, but they typically go out with the 728s for large jobs. Trying to find a good deal on some IT4Ks, or I might just bite the bullet and find some Crest CAs and deal with the weight.

Neither Crest CA nor old-iron Macrotech are class D. Seriously, get a class D amp and the difference is pretty stunning.

I've run 4 SRX728S off a pair of Itech 12000HD a few times and the amount of bass is quite impressive. Easily enough for several thousand people.

I don't think you fully realize what you're missing.
 
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Waiting to get paid for a job then going to be ordering up supplies to build the first cab a mate. Art, do you reckon an I-Tech 4000 would be adequate, or would it be better to step up to the 6000?

I-T4000 20 Hz - 20 kHz Power
1,800W 2-ohm Dual (per ch.)
2,000W 4-ohm Dual (per ch.)
1,250W 8-ohm Dual (per ch.)
3,600W 4-ohm Bridge
4,000W 8-ohm Bridge

I-T6000 20 Hz - 20 kHz Power
2,500W 2-ohm Dual (per ch.)
3,000W 4-ohm Dual (per ch.)
1,500W 8-ohm Dual (per ch.)
5,000W 4-ohm Bridge
6,000W 8-ohm Bridge
 

Art Welter

Senior
Jan 11, 2011
832
19
18
Florida
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Waiting to get paid for a job then going to be ordering up supplies to build the first cab a mate. Art, do you reckon an I-Tech 4000 would be adequate, or would it be better to step up to the 6000?

I-T4000 20 Hz - 20 kHz Power
1,800W 2-ohm Dual (per ch.)
2,000W 4-ohm Dual (per ch.)


I-T6000 20 Hz - 20 kHz Power
2,500W 2-ohm Dual (per ch.)
3,000W 4-ohm Dual (per ch.)
I have not compared the I-Tech 4000 or 6000 to any amp I know, so don't know how much "real" sub power they do.

Although class D can be more power efficient, I don't share Silas' opinion of a "stunning" sonic difference (the Crest CA series kick ass for sub use), though I sure like the 7 pound Speakerpower SP4000 plate amp for driving a pair of Lab 12s. Rated at 4000 watts at 2 ohms, it is "just right" for the WS 2x12" cab.
Speakerpower is also making rack mount amps too now, lighter, about 10% more power efficient, and way more power at 2 ohms than the I-T 6000.
The SP2-8000 is 4000 watts per channel at 2 ohms for $2,495.00

The current limiting of the ITechs at two ohms is a concern, the pair of Lab 12 drop close to 2 ohms at the impedance minima, the limiting may sound flabby on peaks.
Without hearing them, I'd definitely want to err on the side of headroom and go with the 6000 given those two ITech amps as the only choice.

Art
 
Last edited:
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

I have not compared the I-Tech 4000 or 6000 to any amp I know, so don't know how much "real" sub power they do.

Although class D can be more power efficient, I don't share Silas' opinion of a "stunning" sonic difference, though I sure like the 7 pound Speakerpower SP4000 for driving a pair of Lab 12s. The SP4000 is about 10% more power efficient than the Crown.
Speakerpower is also making rack mount amps too, lighter and more power at 2 ohms than the I-T 6000.
The current limiting of the ITechs at two ohms is a concern, the pair of Lab 12 drop close to 2 ohms at the impedance minima, the limiting may sound flabby on peaks.
Without hearing them, I'd want to err on the side of headroom and go with the 6000 given those amps as the only choice.

Thanks Art. Really appreciate the input, and the patience with my 1000 questions.
 
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Stack of four Dual Lab 12 Subwoofers. Crossover set as Jeff specifies on page one (30Hz high pass, 80Hz low pass), Itech for power. Tried out lots of EDM tracks with low bass, standing next to the stack during low notes was enough to make you feel a bit dizzy, if you have never experienced solid performance below 40Hz you are missing out imo. Also listened with a lot of rock and country tunes that I had on my iPhone and was impressed with the sound, without any EQ they seem to have even response across their range.

All in all, as a very novice cabinet builder I've got about eight weeks into the four cabinets, usually working about 3 hours a night for 3-4 nights a week. I'm sure some more experienced guys like Art or Marjan could find loads of mistake - because I made tons of them - but anyone who can operate a table saw and a router should be able to bang these boxes out.

Also, need to hit the screw and bolt heads with a spray bomb, they stick out like a sore thumb.

Photo 2013-07-30 11 38 12 PM.jpg

Thanks again Art for providing this project. I encourage anybody that's been eyeing up the plans to dive in and give it a try.

Edit: Will try to snap a better (less grainy) photo next time I have them set up.
 
Stack of four Dual Lab 12 Subwoofers. Crossover set as Jeff specifies on page one (30Hz high pass, 80Hz low pass), Itech for power. Tried out lots of EDM tracks with low bass, standing next to the stack during low notes was enough to make you feel a bit dizzy, if you have never experienced solid performance below 40Hz you are missing out imo. Also listened with a lot of rock and country tunes that I had on my iPhone and was impressed with the sound, without any EQ they seem to have even response across their range.

All in all, as a very novice cabinet builder I've got about eight weeks into the four cabinets, usually working about 3 hours a night for 3-4 nights a week. I'm sure some more experienced guys like Art or Marjan could find loads of mistake - because I made tons of them - but anyone who can operate a table saw and a router should be able to bang these boxes out.

Also, need to hit the screw and bolt heads with a spray bomb, they stick out like a sore thumb.

View attachment 7611

Thanks again Art for providing this project. I encourage anybody that's been eyeing up the plans to dive in and give it a try.

Edit: Will try to snap a better (less grainy) photo next time I have them set up.

Nice. Any idea what they weigh?

What/who's handles did you use? Good handles make all the difference when moving cabs around.



Sent from my iPad HD
 
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

Nice. Any idea what they weigh?

What/who's handles did you use? Good handles make all the difference when moving cabs around.



Sent from my iPad HD

Not sure on weight, I think it was mentioned earlier that they are around 100lbs loaded and I would think that is pretty close to accurate. I used one brace from baffle to back (3" wide piece of birch running between the drivers), the port walls seem to make the rest of the cabinet pretty stiff so I don't think any other bracing is necessary. I can lift one and stack it on another by myself although I'll opt for a helper whenever possible. It's also worth noting that I am 26 years old, 5'11 and 270 lbs and regularly stack dual 15 tops on dual 18 subs by myself, fight loaded amp racks out of the van solo, and all the other things that I'm sure will catch up with me in 10 years, so take what I say with a grain of salt.

Handles are from Penn Elcom, asked my contact there to recommend a set that wouldn't vibrate and so far it seems he delivered. I would have to look up the exact model. Grill was from Penn as well, air conditioner filter was attached using 3M spray glue but it was hard to keep the foam attached to the grill without making a mess with the glue. I would welcome any ideas on how to make the grills look cleaner because at this point they are the only part of the project that I'm not happy with.

The box goes together pretty quick, the port construction takes a bit of time however. I cut long strips of the 3/4" wedge and trimmed them to size on a radial arm mitre saw, wood filler and paint covers up lots of mistakes. :)
 
Sep 12, 2012
647
5
18
SW Ontario
Re: FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems

It looked to me that you cut holes in the sides for the handles and made a cover of wood for the inside? How did you minimize the impact on the ports?

What would you do differently?


Sent from my iPad HD

The first cab is just holes through the sides of the box, for the other three I set my router to the depth of the handles and made a pocket rather than going all the way through. In listening I can't hear a difference - with the grills on I can't tell which cab was the prototype, I'm interested to see if there is a measurable difference.

Doing one cab to start was a good exercise, I noted any mistakes that I made during the first build. Buying good blades and router bits made a big difference.