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.
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.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, 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.
May or may not have just ordered 6 more Lab 12 drivers... ~:-D~:grin:
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.
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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?
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