c.cam108 Posted January 21, 2011 Share Posted January 21, 2011 Just a quick question. I'm looking to fly a couple of these using eyes into the rigging points. I will take two wire ropes from the side rigging points right up to the ceiling, but what about angling the box down. Do I need to take the third wire from the bottom right to the roof? Or can I use dogs to clamp it to the two side support wires (I suspect not, but more on an aesthetic standpoint than anything else). Actually, thinking about it, taking it right up would give a tertiary support - belt, braces and gaffer, if that's the right analogy :). Also, this wire will be bent over the bottom rear corner of the box. Do I need to protect it from kinking? Thanks Colin C Link to comment Share on other sites More sharing options...
ramdram Posted January 21, 2011 Share Posted January 21, 2011 Can I suggest you rootle out the "approved" method statement for flying/hanging the units from the manufacturer before you hang anything? This is for your protection, not so much from falling kit but writs falling on your head. The idea that the wire, any wire, might be kinked is something you need to reconsider asap. Granted the units are not heavy but the suspension points, in the ceiling that is, should be capable of bearing the load as well. Apologies if you are aware of this anyway, but the notion of asking what amounts to H&S advice on a project that only you have seen is a bit tricky for anyone else, hence the RTM suggestion. I'm going to presume there are no convenient walls nearby to allow for a properly designed and built speaker mount? I have exactly the same job on hand as I type and am using swing and tilt wall mounts more than capable of bearing the load and will use safety wires onto a separate fixing. HTH Link to comment Share on other sites More sharing options...
Simon Lewis Posted January 21, 2011 Share Posted January 21, 2011 These boxes do come with a mounting bracket.As Ramdram mentions, they're not a particularly heavy box, but in the apparent absence of any documentation on the LD website, it's not clear that they are meant to be "rigged" as opposed to "mounted". It may be academic given the light loads involved, but putting eyebolts on the side of a cabinet is rarely satisfactory - the load should be in line with the plane of the eyebolt and within the pull angle stated by the manufacturer. That can be hard to achieve when it's at 90 degrees. If I was flying them, I'd rather have a yoke fixed to the box (which would help to get the angle needed) and fix the flying wires to the yoke. Depending on where the centre of gravity was, it might still need a pull back. Link to comment Share on other sites More sharing options...
paulears Posted January 21, 2011 Share Posted January 21, 2011 The other to watch is the side mounting points - Having seen some of these once (I think) I thought they were suspended from a bracket fixed to the wall that then attached via those side threads - so the tilt angle could be adjusted. Sticking some cable hanging hardware in them could be a problem - if the side points are intended for a bracket which, as it touches the side walls, evenly compresses and the threaded hole could just be one of those top hat with three spike fittings that dig into the MDF. Perfectly fine with a proper bracket, but not good for suspension from above - when they could potentially pull out. Unlikely, but possible. Thomann had a warning on one of the T-Box products that the mounting points must NOT be used for suspension. Simon's cradle idea is a good one - and you'll find plenty of metal fabricators willing to knock one of these up for you. They will no doubt weigh more than the speakers, but where the manufacturer is cagey about flying, it's worth doing. Link to comment Share on other sites More sharing options...
ramdram Posted January 21, 2011 Share Posted January 21, 2011 The other way of looking at the issue, providing the funding is available of course, is to buy speakers and "matched" suspension system and hang the units as designed by the manufacturer. I have to say that from reading the other posts the amount of effort may not be worth it as the money spent on "alternative" solutions might just as well be spent in buying a product designed to be used as you want. The result would be zero time wasted in explaining to the 'smiths what you were trying to achieve. Zero time wasted on evolving the suitable wire(s) rigging points for getting your desired angle and dangle. And you would be OK from the H&S perspective as you were using kit "fit for purpose" straight out of the box. Link to comment Share on other sites More sharing options...
paulears Posted January 21, 2011 Share Posted January 21, 2011 Oddly - my venue still has a pair of Shure Vocal Master columns hung from the ceiling of the auditorium, via some ancient wire rope, a variety of mismatched dogs, a few nails and assorted screws driven direct into the sides. They've been there since the sixties, are not wired to anything - but cannot be touched because the cables are poked through holes in an asbestos ceiling, and the roof side support is officially a place where nobody is allowed to go - the local authority having requested the removal of the roofspace walkway for safety reasons. So in an ideal world, they should be took down, but taking them down is deemed a safety hazard worse than the non-Shure approved fixing. "They've been perfectly safe for 40 years, so why mess with them now?". Link to comment Share on other sites More sharing options...
c.cam108 Posted January 21, 2011 Author Share Posted January 21, 2011 Thanks for the advice guys. There is no wall nearby for about 10m, so a boom arm would be a bit awkward :P. I'll contact LD and see what they say about the rigging points, but they did look like a large plate screwed through the MDF. Obviously I wouldn't go near T-nuts with an eyebolt. I'm sure I've seen the product with a bracket, but IIRC it attaches to the top and bottom. I was not too concerned with the pull angle on the eye bolts. I had a look at some from Flints and found a datasheet stating a de-rating factor of 50% when the pull angle is 90 degrees. This is on a fixing with an SWL of 250kg (figures from memory, but still well over 7.7kg). Colin C Link to comment Share on other sites More sharing options...
ramdram Posted January 21, 2011 Share Posted January 21, 2011 Crikey Paulears you must have the luck of the Irish! Surely the wires should be inspected at least every 39 years or so to check for corrosion, loose fixings etc, etc. Can you imagine if one of the wire cables decided to let go? It might bring the ceiling down as the weight "moved" slightly. The cost of cleaning up, binning and burying the asbestos would be quite dear, let alone cobbling up a new ceiling and speaker suspension systems and speakers. I believe this is one of those scenarios where it might be a shrewd notion to have a look at the assembly as soon as, and, if necessary, simply crop the wires just under the ceiling. Link to comment Share on other sites More sharing options...
paulears Posted January 21, 2011 Share Posted January 21, 2011 Indeed - this was my exact plan, but the management of the venue believe everything the asbestos specialists tell them - and maybe one day I'll do exactly this - but the problems of taking the weight off the cables and then snipping mean it's a scaff tower access and that means time, and time means money, and ... you can see where it's going. Going back to the fixings - the eye-bolt isn't the problem really - if you use a spreader plate when you screw it in. It may well have just a T-nut inside - and that would not be good without the clamping the spreader plate would provide. The eye-bolt screwed into one of those direct - and then used to hold a speaker with a side force could well gradually compress the MDF and pull out - hopefully just getting loose first? EV300s are a good example where there are top and bottom threads and the proper cradle is a pretty meaty affair - somehow, just hanging one from a single point is asking an awful lot from moulded plastic? Link to comment Share on other sites More sharing options...
Seano Posted January 21, 2011 Share Posted January 21, 2011 Or can I use dogs to clamp it to the two side support wires (I suspect not, but more on an aesthetic standpoint than anything else).Yep. While it wouldn't be horribly unsound, it would certainly be quite smelly, aesthetically.If you wanted to do this you could perhaps make a little bridle there, so that rather than the end of one wire rope joining another in the middle somewhere you bring the ends of three ropes together via a shackle or o-ring. Also, this wire will be bent over the bottom rear corner of the box. Do I need to protect it from kinking?That's all about the R/r ration, and really shouldn't be a problem, given that you're unlikely to be talking about a particularly fat wire rope, or anything over a small fraction of its SWL. If you want to protect the rope, a bit of suitably sized PVC tubing over the wire should suffice. (And will also protect the corner of the cabinet from chafing against the wire.) But having said that, I'm inclined to agree with Simon & Paul, that hanging directly from the "rigging points" might not be ideal. Can I suggest you rootle out the "approved" method statement for flying/hanging the units from the manufacturer before you hang anything?Doesn't seem to be one as far as I can tell, that's rather the problem. It might be worth getting in touch though, to see if they have more to offer than is on their website? Simon's cradle idea is a good one - and you'll find plenty of metal fabricators willing to knock one of these up for you.Yep, I think I'd go along with that. Best to apply the KISS principle to the design of the 'cradle'. Indeed - this was my exact plan, but the management of the venue believe everything the asbestos specialists tell them - and maybe one day I'll do exactly this - but the problems of taking the weight off the cables and then snipping mean it's a scaff tower access and that means time, and time means money, and ... you can see where it's going.Holy cow. Its not a lot of time and money is it - a scaff tower, a pair of Felcos and a day's work. Crazy. (But no surprise I guess.) Link to comment Share on other sites More sharing options...
Chas at Halls Posted January 21, 2011 Share Posted January 21, 2011 We have a picture on our website of a piece of steel wire rope that 'hadn't been looked at' for 10 years.... http://www.hallstage.com/images/stories/disaster%20rigging.jpg No names, no pack-drill.....but all better now obviously. It was holding up a lot more than a speaker cab too....! Chas at halls Link to comment Share on other sites More sharing options...
c.cam108 Posted January 21, 2011 Author Share Posted January 21, 2011 Yep. While it wouldn't be horribly unsound, it would certainly be quite smelly, aesthetically.If you wanted to do this you could perhaps make a little bridle there, so that rather than the end of one wire rope joining another in the middle somewhere you bring the ends of three ropes together via a shackle or o-ring.Thanks for the idea. That would be a lot neater.That's all about the R/r ration, and really shouldn't be a problem, given that you're unlikely to be talking about a particularly fat wire rope, or anything over a small fraction of its SWL. If you want to protect the rope, a bit of suitably sized PVC tubing over the wire should suffice. (And will also protect the corner of the cabinet from chafing against the wire.)I'll work it out. Should be quite low. I was thinking maybe only using even 3mm rope for such a light load.Can I suggest you rootle out the "approved" method statement for flying/hanging the units from the manufacturer before you hang anything?Doesn't seem to be one as far as I can tell, that's rather the problem. It might be worth getting in touch though, to see if they have more to offer than is on their website?Got this back from LD: Dear Colin, Yes they have a rigging point on the top which you can screw a eye bolt in and fly. I hope this helps. Best regards Lee For reference, this is what I asked: Please could you advise me about the rigging points on the LD SAT82? Are they suitable for attaching an eyebolt to hang the speakers from wire rope? If not, could you please advise on the preferred way of flying these speakers?Not sure that only using the one hanging point is the best idea, but I suppose that is my answer right there.Colin C Link to comment Share on other sites More sharing options...
paulears Posted January 21, 2011 Share Posted January 21, 2011 A bit O/T but when we had our wire rope replaced on the counterweight system, the report that made sure it happened by the engineers read "what follows is the approved method of joining steel wire rope - please note, a Reef knot is NOT sufficient!" When the original system had been fitted in the late 50s, one drop went the wrong side of a steel I beam - and by 2007 had sawed an inch into it! Link to comment Share on other sites More sharing options...
c.cam108 Posted January 21, 2011 Author Share Posted January 21, 2011 A reef knot in wire rope? Will that even stick?? Link to comment Share on other sites More sharing options...
Simon Lewis Posted January 21, 2011 Share Posted January 21, 2011 I was not too concerned with the pull angle on the eye bolts. For the application you describe, this may not be an issue. However, at a Crosby training session last year, the facilitator stated that they provide a rating for shouldered eye bolts only in the plane of the eye. If the load is not in this plane, it has no rating associated with it. They said that obviously it has its inherent structural strength, but they would not put a figure on it - which has obvious implications. Unless you use packing shims, it's hard to get an eyebolt to line up properly on the side of a box.Of course, you may be looking at a different manufacturer who does not apply this restriction. Link to comment Share on other sites More sharing options...
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