OT12 Install Build

[gdougherty]

http://picasaweb.google.com/georgedman/OT12Install
Finally got them hung Wednesday and went back this morning to tweak everything beyond the auto-eq and rough balance work I'd been able to do Wednesday evening. I'm pretty sure I got my internal wiring correct but flipping polarity on one of the speakers seems to have gotten things working balanced out in the middle of the room. I didn't have time to pull cables apart but I was using previously installed wiring so i can't vouch for its correctness. Thankfully I can get up on a ladder and pull the back off without taking down the speakers.

The result? You can see the three black Mackie speakers still hanging from the ceiling they replace. The Mackies had two zones where they transitioned which was right in the middle of a section of pews. Also we had problems getting enough of an angle on the center speaker to cover front to back evenly. As high as it mounted to the ceiling it just wasn't ideal for vertical coverage.

Coverage with the two low-hanging OT12's is significantly better. The only transition is in the middle aisle and with the additional tweaking the aisle zone sounds perfect as well. The 120 degree coverage of the melded array gets the entire width of the room and the lower angle allows for more even coverage front to back. The front row now has better high frequency coverage and there's not a bad seat in the house.

You can see the large wooden table up front in some of the pictures. The next plan is to pull it apart and replace the front panel with a large section of grill cloth, put a plywood bottom on it to stabilize the sides, and slide a T48 inside it. Right now the T48 hides off to the side for the Saturday church. My church on Sundays moves the table and covers the T48 with a table cloth in its place.

Build cost for the OT12's, a single 30" T48, and adding a DCX2496 for management duties will be about $1100. My best guess on the Mackies is about $1500 or better for the trio and they can't hold a candle to the sound of the BFD system. The T48 hits hard on the bottom end and has plenty of output to bump the 60-30Hz region with EQ without worrying about damage to the 3015LF. In testing I had the OT12's up painfully loud without distortion and they'll never even come close to that volume in normal usage.

The OT12's truly have a hi-fi sound. Even without things set quite right, comments Wednesday night were that it was hands down the best sound we'd ever had to work with period. Despite the better coverage up front, we had more gain before feedback on the headset wireless mic worn by the pastor sitting up about the front pew row and less room noise. The tight vertical pattern on the tweeter array helps control noise in the room and with a bit of absorption across the back walls someday, should improve even more.

[Les Webb]

Really nice. The white look is very custom. From one of the pics it looks like the OTs might interfere, for a small section of viewers, with the visual of the screen. Is this the case or is is just camera angle?

[gdougherty]

Thanks. Everyone I've talked to has been impressed by the level of finish and a few even wanted to know what brand they were.
As to blocking the screen, they do. Fortunately neither of our congregations pack the room and for a chunk of the area where they do block more, the beam already blocked some of it. Additionally, when you're seated, the area that's affected is smaller and as you move to the back the blockage gets smaller in relation to the screen.

[Alan Star]

Yeah, they look great, really nice work there. Thanks for the review and info, and the Wedgehorn review too.

[Harley]

Nice looking job there!

[jbell]

nice cabinets.

Not too sure on the zip ties... however. My local inspectors would fail it.


Is your safety cable hidden? (a cable that is not part of the primary suspension, capable of supporting the entire weight, plus any additional dropping force of the cabinet?)

I have to install them on anything overhead. (I've even been questioned on projectors, and usually run an 1/8" cable through the center of the pole, to the kensington lock on the projector.)

I do use turnbuckles (with lock nuts) where you used zip ties. Painted white would add a level of safety, and good looks to outstanding looking cabs.

well done.

[gdougherty]

nice cabinets.

Not too sure on the zip ties... however. My local inspectors would fail it.


Is your safety cable hidden? (a cable that is not part of the primary suspension, capable of supporting the entire weight, plus any additional dropping force of the cabinet?)

I have to install them on anything overhead. (I've even been questioned on projectors, and usually run an 1/8" cable through the center of the pole, to the kensington lock on the projector.)

I do use turnbuckles (with lock nuts) where you used zip ties. Painted white would add a level of safety, and good looks to outstanding looking cabs.

well done.

I'd originally purchased metal hardware and a turnbuckle to allow adjustment of the front angle. Problem was the turnbuckle was too long and I'd forgotten to measure the width of the beam area so the back eye bolts were too wide to use the hooks I'd planned for the back. I want to keep it as tight to the beam as possible so I have to figure out something else. The zip ties were on hand and the tensile strength seemed adequate for the short term. Long term especially I'd worry about the zip ties getting hard and fragile. I hadn't thought of a backup cable since failure of the 4" eyebolts up into the beam or metal hardware seemed highly unlikely and they're too high to get idiots swinging from them.

[jbell]

I know, I know....
Everything I hang is minimmum 1/4" diameter or heavier hardware. However codes are codes. The theory is that either the mounting points, or the connection material itself can vibrate lose, fail, etc... Look in any commercial building, every light fixture, every everything has a safety cable...

For your yearly fire marshal / codes inspection, they 'should' look for it.

Even with turnbuckles, I use jam nuts and locktite.

If you run a lightweight cable (1/8" would do) in/out of one of your ports, through a hole drilled in a horn mouth brace -- that would be easiest, cleanest.

BTW -- I love church's... pretty cool what you did for them.


For your rear mounting points, I'm a fan of locking carabiner's

[Tom Smit]

jbell,I'm curious about the safety cable...#1-may the cable have u-clamps installed on both ends......and #2-does the cable have similar attachments to cab and to support as the regular mounting hardware...finally #3-may the safety cable be attached at/near the same location as the regular hardware.

Thanks, TomS

[DAVID_L_PERRY]

The build looks great but damn....zip ties....... ........

[Tim A]

The build looks great but damn....zip ties....... ........

Yeah, that's a bit on the scary side.

JBell, I've never been able to find locking carabiners locally that are approved for overhead lifting. Where do you get yours?

[Bill Fitzmaurice]

JBell, I've never been able to find locking carabiners locally that are approved for overhead lifting. Where do you get yours?

Eastern Mountain Sports, LL Bean, any sporting goods store that sells climbing gear.

[jbell]

I don't want to hijack, the White OT12's are AWESOME!!! and I really can't stand to see the obviously bad installs in church's I see all the time. So for your OT12's -- way to go. I wouldn't feel bad for a church with that kind of set up. With your original 3 speaker mount, I bet it was challenging, to say the least, and %Alcons had to be terrible.

However,
I think you mean for your inspection guy, what's rated for overhead rigging? aka, clevice vs carabiner?

Well, clevice is always acceptable, but I've been doing carabiner's lately, as they are the easy ticket for the initial hang. I got questioned on it once, and provided the following quoted info, and was never questioned again. (Although if I'm doing eaw's.... well, I only use approved hardware)

QUOTE/
carabiner strength is measured in kN (kilo-Newtons), which is a fall-force measurement: one kN equals 225 pounds. The UIAA minimum acceptable strength is 23 kN
/QUOTE

(NOTE you must use the locking style, or the threaded 'c clips' which really isn't a carabiner, and is actually a bigger pain on install.)

[gdougherty]

The build looks great but damn....zip ties....... ........

True, and not a long term solution but consider.
1 zip-tie = 75lbs tensile strength. As a test, I strapped one zip-tie to one mount point while getting the speaker up there on my own. Held fine with the entire ~35lb speaker and a little extra pull. The three mount points all have doubled zip ties and all the mounting hardware is 1/4" so there aren't any small hard edges to work their way through the plastic. In theory, though I don't think I'd want to risk my life on it, I've got 450lbs of strength holding up 35lbs of speaker. In the short-term I'm not worried about it falling on anyone. Before the plastic becomes brittle I should have metal hardware up there.

[Harley]

...In theory, though I don't think I'd want to risk my life on it, I've got 450lbs of strength holding up 35lbs of speaker. In the short-term I'm not worried about it falling on anyone. Before the plastic becomes brittle I should have metal hardware up there.

I learned the strength of those plastic ties when a battery holder in my Volvo fell to bits and I was milse away from anywhere decent to have th bracket welded. Those plastic ties continued their service right up until the Volvo was used in a demolition derby.

My son had an accident in it and the panel damage repair value exceeded the insured value, so in conjunction with the insurance co, we donated it to a guy who ran stock cars and it lasted in that derby up until 7th out of 200 cars!! The guy reckoned he never touched the battery or those ties...

But you are right, after a short period of time those ties will deteriorate through UV damage and becoming brittle.