Hanging a decca tree

Discussion in 'Location Recording' started by FifthCircle, Dec 9, 2005.

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  1. FifthCircle

    FifthCircle Well-Known Member

    Has anybody done this?

    I usually use Decca trees in session situations where mic stands don't matter. However, I just got 2 more omnis to add to the collection which means I can do a Decca tree and flanks. I have some gigs on the horizon where this would probably sound pretty awesome, but I need to be able to hang my microphones.

    I know AEA makes a tree that you can fly, but it costs over $1000 and I can find better things to do with that kind of money (no offense to Wes and his great products, but I need more mics and pres). I'm not opposed to trying to do something like this home brew, but I'm not sure where to start. The big thing will be having the ability to change my spacings on the mics and keeping the whole rig balanced so that it can be suspended from the ceiling and then tied back to a lighting grid...
    --Ben
     
  2. Zilla

    Zilla Active Member

    Ben,

    Give me a call. I got what you need.
     
  3. DavidSpearritt

    DavidSpearritt Well-Known Member

    Scott, could you please elaborate on the forum.
     
  4. Zilla

    Zilla Active Member

    I designed a light weight and easily deployed flying decca tree assembly. Once in the air it can be moved/pulled into position, all the time maintaining its attitude (it stays level).
     
  5. DavidSpearritt

    DavidSpearritt Well-Known Member

    materials, design, pictures? :)
     
  6. Cucco

    Cucco Distinguished Member

    A very cheap solution is to take Aluminum Hex rod in 6 foot and 3 foot lengths (1 of each length) and braze them together to make a short, fat 'T'. You can then use the microphone positioners that come with the Sabra Som mic mounts to position the mics (slide them back and forth.)

    Then, for leveling, get a bubble level which attaches via velcro straps (readily available at Lowes and Home Depot and camera stores).

    For hanging - Braze eyelets onto the top of the 3 sections and the middle of the 'T' and you're good to go.

    The assembly won't be all that heavy - less than the mics that will hang on it, and the brazing will be far more resistant to breaking than solder.

    The rods can be purchased at:
    http://www.smallparts.com


    J. :cool:
     
  7. zemlin

    zemlin Well-Known Member

    I use the Sabra stuff for things like this. I bought my hex rod at http://www.mcmaster.com - my favorite shopping site.
     
  8. mdemeyer

    mdemeyer Active Member

    Jeremy,

    I think you once mentioned some kind of hex rod that was not as resonant as the aluminum rod that seems to be easy to find. Can you point me to that? I have 2 and 3 foot rods of both stainless and aluminum, but they both ring a lot and I have not found a good way to damp them and still be able to slide the Sabra mic mounts around.

    Michael
     
  9. DavidSpearritt

    DavidSpearritt Well-Known Member

    I was thinking of using more of this spar for the main and cross pieces:
    http://www.kitepower.com.au/catalog/product_16837_Flexifoil_Carbon_Centre_Spar_cat_306.html

    and these to glue the mic mounts to, which then slide and rotate around the axis of the tube at will.
    http://www.kitepower.com.au/catalog/product_16836_Flexifoil_Brass_Ferrules_cat_306.html
     
  10. DavidSpearritt

    DavidSpearritt Well-Known Member

    I have already used Glaspar J65 tubes from this brand:
    Line 6 Manuals

    There are some wonderful fittings that suit joining the tubes at 90 degrees and some you can bolt a mic clip to. These tubes are very light, very stiff and very straight.
     
  11. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    A couple of ways to damp the ring. Go to Lowes or Home Depot and go to the section where they have calking supplies. There in bags you will find coils of plastic foam that is suppose to be used for filling in large cracks before you calk them. You can find them in different diameters and all you have to do is find one that is about the same OD as your tubing is ID and put it into the tube. A couple of cap plugs at each end and you are done. You could also fill the tubes with sand or lead shot but that would add to the overall weight. While you are at the calking section look for expanding foam. You would have to also purchase a long piece of vinyl tubing that you could put over the nozzel that is on the can of expanding foam so you can shoot the expanding foam down the tubes. Put a cap over one end and use the expanding foam to fill the tube until you get to the other end and then put a cap plug over that end. Watch the expanding foam it goes in fast and if you get it on something it is sometimes hard to get off (personal experience) I would try it first on a piece of tubing before trying it on the flying rig.

    Hope this helps.
     
  12. mdemeyer

    mdemeyer Active Member

    Hi Tom,

    Unfortunately, I'm referring to the 3/8 Hex rod, which is solid. Or is there a hollow version of this which can then be internally damped by the techniques you mention?

    Michael
     
  13. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    I have seen various hex shaped extrusions in catalogues and here on the web

    http://www.mfgquote.com/profiles/Hollow-Shape-Extrusions-58658-Fort-Collins-Colorado-United-States.html

    http://www.americanaluminum.com/aluminum-extrusions/aluminum-shapes.htm

    http://www.thermoprene.com/scripts/aluminum_extrusion.asp

    and

    http://www.metricmetal.com/hex.htm

    but you could also use square tubing which I saw today at Lowe's

    I made my flyable MS assembly out of aluminum pipe and brass adapters. It is a bit heavy but not too unmanageable. I have seen the AEA units and they are beautifully made and EXPENSIVE. For adapters I used some ATLAS adapters which work well. I use the ALTAS Sound MAC-1s or the CO-1Bs depending on what I am doing. I also use chemical labratory stand right angle clamps that I find at an Industrial Surplus place near here. I put a short Atlas AD-8B on one side of the 90 degree clamp and clamp the other side to the Decca Tree horizontal member. This gives me lots of flexibility. It is amazing what you can find to work with, you just need some creative thinking.

    Best of luck!
     
  14. DavidSpearritt

    DavidSpearritt Well-Known Member

    I am surprised you guys are talking about heavy metal rods and tubes for such an application. Imagine the thing falling during a concert and taking out a couple of Strads in the first desk, plus clouting the conductor. Do you have lots of indemnity insurance cover? Lots?
     
  15. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    Well that is a very good point David and I have seen some really nasty things hanging above the conductor's head.

    You have to know what you are doing and have to way the risk against what you are being asked to do.

    Many times lately I have been asked to "make the microphones disappear" but the group still wants perfect audio recorded. This is not the 1950's and audience members should be use to seeing a couple of microphone stands without taking offense to their being on stage or in the audience. I prefer to record with a stand for my Decca Tree but if forced there are other ways of doing things as long as you understand the risks.

    I have been in concerts were there was mulitple tons of flying speakers above the performer's heads but they had good riggers and the the risk was very low. I have also seen microphones hung on a wire crash to the floor when the wire broke at one end and the the microphones came down hard. I also witnessed a whole lighting trust breaking free in a stage play and drop down on one end. These were all preventable but some how they happened. If you do not know what you are doing then you should hire someone who is a certified rigger and if there is a problem it is his neck on the line and not yours. Some houses I have worked in refuse to have anything flying above the heads of the performers or audience for just the reasons you have stated. Whether the microphone mount is heavy or not heavy the microphones certainly are heavy and can become missles if the mounting breaks. I don't know if you remember that at one point performers use to swing their SM58's above their heads in an ever widening circle (but they had specially designed mounts on the microhone) One day a student in a rock concert decided to start swinging the microphone around his head and after about 3 minutes of doing it the microphone seperated at the XLR connector flew out in the audience and put a really big dent in the seating. I could just imagine if that had been someone's head, luckily there was a very small audience and a very big hall.

    Good point and I am glad you raised it.
     
  16. Cucco

    Cucco Distinguished Member

    That's it in a nutshell.

    Oh, and I've got $1Mil per incidence in liability - enough to cover almost any instrument. (almost...). It's crazy to do what we do without that kind of coverage!!!

    I was almost accused of setting a theater's light system ablaze one time (a $75K problem!!!) Their blowers were so loud, I asked someone to place a cloth baffle over the opening (but not so close as to block the opening - simply shield it.) The stage engineer blocked it completely and forgot to take it down over night. When they came back in the next day, the lights had powered themselves off and when they went to restart them, the system blew up (literally...)

    Since I didn't actually do the baffling and wasn't responsible for taking it down, I was off the hook, but that doesn't mean that the dude responsible for it didn't try to blame me!

    J.
     

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