Skimble Posted November 12, 2013 Share Posted November 12, 2013 I am looking to mount a speaker on a near-vertical beam in our school hall. The biggest complication is that the beam is angled in slightly, so that the top of it is a couple of feet further into the hall than the bottom. I need to mount the speaker on a beam because the rest of the 'wall' is glass, which I understand isn't such a good material to mount speakers on..! Link to comment Share on other sites More sharing options...
ImagineerTom Posted November 12, 2013 Share Posted November 12, 2013 If you know what you're doing this is a relatively simple job - there's beam clamps, girder clamps and a whole host of other mounting devices available easily and relatively cheaply - however because if you get this wrong stuff falls and hits people on the head this is one of those situations where the only advice anyone can give you is to get someone in who does know what they're doing. A lowly builder or middle-of-the-road lighting and sound company could knock together the proper kit, do the proper sums and have you something in within an hour. Link to comment Share on other sites More sharing options...
top-cat Posted November 12, 2013 Share Posted November 12, 2013 I suppose though, Tom, it does depend on what we are talking when we say beam! Construction whether it's wood, steel, etc. Shape, whether there's a flange to fix into of if it's just box. If its part of a window frame then obviously you cant go around the beam. Also whether drilling into it is permitted or not. Unfortunately often schools can't answer these questions as the buildings are old and have been passed from generation to generation of heads and theres no real record kept of who you could call about it. S whilst yes the bracket might be an easy construction, finding out how, and where, and how much you can rig on the beam may be a more complex process. Link to comment Share on other sites More sharing options...
Brian Posted November 12, 2013 Share Posted November 12, 2013 Perhaps if the OP could post up a decent picture of the beam in question? Link to comment Share on other sites More sharing options...
indyld Posted November 12, 2013 Share Posted November 12, 2013 ... I need to mount the speaker on a beam because the rest of the 'wall' is glass, which I understand isn't such a good material to mount speakers on..! Ah, the glass wall. So beloved of the sound engineer :-D Link to comment Share on other sites More sharing options...
ImagineerTom Posted November 12, 2013 Share Posted November 12, 2013 I suppose though, Tom, it does depend on what we are talking when we say beam! Construction whether it's wood, steel, etc. Shape, whether there's a flange to fix into of if it's just box. If its part of a window frame then obviously you cant go around the beam. Also whether drilling into it is permitted or not. Unfortunately often schools can't answer these questions as the buildings are old and have been passed from generation to generation of heads and theres no real record kept of who you could call about it. S whilst yes the bracket might be an easy construction, finding out how, and where, and how much you can rig on the beam may be a more complex process. ...and thus we come back to the main piece of advice I gave which was that you just need to get someone in who knows what they're doing. If it's a 12" steel beam then a lack of construction history isn't an issue and subject to a quick inspection to make sure it's affixed to other similarly solid metalwork I'd be more than happy to rig a 15kg speaker cab off it and would probably knock together an installation point using unistrut http://www.blue-room.org.uk/public/style_emoticons/default/biggrin.gif. Whilst by posting a picture of the problem we can all chip in vague ideas absolutely every possible resolution to this problem requires getting someone in with the right skillset. It's such a basic job though it's the sort of thing I'd do "for a pint" if I was local - perhaps the OP could provide a slightly more specific location as there could well be other Blueroom members closeby who could pop in and help? Link to comment Share on other sites More sharing options...
top-cat Posted November 13, 2013 Share Posted November 13, 2013 <br /><font color="#1C2837"><font size="2">I suppose though, Tom, it does depend on what we are talking when we say beam! Construction whether it's wood, steel, etc. Shape, whether there's a flange to fix into of if it's just box. If its part of a window frame then obviously you cant go around the beam. Also whether drilling into it is permitted or not. Unfortunately often schools can't answer these questions as the buildings are old and have been passed from generation to generation of heads and theres no real record kept of who you could call about it. S whilst yes the bracket might be an easy construction, finding out how, and where, and how much you can rig on the beam may be a more complex process. </font></font><br /><font color="#1C2837"><font size="2"><br /></font></font><br /><font color="#1C2837"><font size="2">...and thus we come back to the main piece of advice I gave which was that you just need to get someone in who knows what they're doing. If it's a 12" steel beam then a lack of construction history isn't an issue and subject to a quick inspection to make sure it's affixed to other similarly solid metalwork I'd be more than happy to rig a 15kg speaker cab off it 100% agree. and would probably knock together an installation point using unistrut </quote] Careful...! Link to comment Share on other sites More sharing options...
Skimble Posted November 13, 2013 Author Share Posted November 13, 2013 Thank you all. I'm in Bexley, SE London and would happily welcome a visit and could probably even manage 'a pint' for a solution. :) Photo to follow when I get my act together. It's one of five near-vertical I-beams that go up one side of the hall to a height of approx 6m, supporting the roof, which is approx 10m across. It's as thick as the wall, and dates back to the mid-fifties. Link to comment Share on other sites More sharing options...
Skimble Posted November 14, 2013 Author Share Posted November 14, 2013 I can't upload a picture. Each time I insert it into my post I'm told that I must enter a post, but t won't acknowledge it if I paste the picture in. Not sure how else to do it. :( Link to comment Share on other sites More sharing options...
ImagineerTom Posted November 14, 2013 Share Posted November 14, 2013 you have to upload the picture to a filespace somewhere then provide the link... email it to me - thatthomas@me.com and I'll post it up Link to comment Share on other sites More sharing options...
ImagineerTom Posted November 15, 2013 Share Posted November 15, 2013 http://letsdotheshowrighthere.com/uploads/roofsupport1.jpg Link to comment Share on other sites More sharing options...
Skimble Posted November 15, 2013 Author Share Posted November 15, 2013 Thanks Tom! The beam is about 15cm deep at the bottom and gets wider, extending to approx. 35cm 6m up. If you need any more measurements, just let me know, but I'm hoping that one of you will find yourself in Bexley and drop in to have a look. ;) Link to comment Share on other sites More sharing options...
ImagineerTom Posted November 15, 2013 Share Posted November 15, 2013 Personally I'd probably be happy with 4 pipe clamps / beam clamps mounted on a plate to which the speaker was then hung so that the combined effect of the bit of the clamps and the off-centre pull meant the plate was "biting" to the beam" - subject to occasional inspections to make sure it's not moving and everything is tight. However as mentioned above you really need someone with the knowledge to spec the precise shape and combo for you taking in to account all the variables etc Link to comment Share on other sites More sharing options...
Brian Posted November 15, 2013 Share Posted November 15, 2013 I'd either... a) use 4 Lindapters on a plate and, as Tom says, hang the speaker or b) drill a couple of 11mm holes into the flanges of the beam (technically a column as it's vertical) using some 'wedge washers' to level up the nuts and bolt on a bracket to hang the speaker from. Link to comment Share on other sites More sharing options...
ImagineerTom Posted November 16, 2013 Share Posted November 16, 2013 Structural engineer advice and general best practice is not to drill in to "old" structural beams like this - you run the risk of significantly weakening them and you're also exposing the "inside" of the beam to oxygen and moisture thus creating a future corrosion/failure point. It's also a tricky job drilling in to 6mm thick steel whilst on top of a ladder Link to comment Share on other sites More sharing options...
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