The above Ad will no longer appear after you Sign Up for Free!

speaker "yoke" rigging

Discussion in 'Sound, Music, and Intercom' started by jkowtko, Oct 22, 2007.

  1. jkowtko

    jkowtko Active Member

    Messages:
    806
    Likes Received:
    50
    Location:
    Redwood City, CA
    I'd like to put a couple of my Mackie SRM450s in a hanging yoke assembly that I can hang from lighting pipes and move around for different shows. Mackie doesn't have such an assembly for the SRM450, and I've found only a few out there but they are all designed for specific speakers.

    Does anyone know of a company that makes general purpose speaker hanging yokes? Something with a frame that wraps around the speaker (the SRM450 has two m-10 bolt holes on top and two on bottom) with an upside-down U shaped yoke that can be attached to a pipe clamp? Or something similar that will hang from a pipe and give you both pitch and yaw adjustment?

    I'm about to hit up the local iron works company for some custom work, but would like to find something off-the-shelf if possible.

    Thanks. John
     
  2. Footer

    Footer Senior Team Senior Team Premium Member

    Messages:
    9,442
    Likes Received:
    1,846
    Location:
    Saratoga Springs, NY
    I have never seen a "universal" mounting bracket. I have built brackets like that before, but besides EAW and Meyer gear, very few companies make mounts for their speakers.

    If you have a welder and someone who knows how to weld, they are pretty easy to make, any shop should be able to do it pretty easily. I would use a pretty hefty clamp or dual clamps, speakers do put out a bit of force.
     
  3. museav

    museav CBMod CB Mods Departed Member

    Messages:
    4,017
    Likes Received:
    562
    Occupation:
    Acoustical, audio and audiovisual consultant
    Location:
    Marietta, GA
    Allen Products makes some yoke style pole mounts and Polar Focus offers some more generic yokes.
     
  4. CURLS

    CURLS Member

    Messages:
    90
    Likes Received:
    1
  5. avkid

    avkid Not a New User Fight Leukemia

    Messages:
    5,948
    Likes Received:
    225
    Occupation:
    Stageline Operator/Staging Supervisor
    Location:
    Howell, NJ
  6. BillESC

    BillESC Well-Known Member Premium Member

    Messages:
    2,321
    Likes Received:
    356
    Location:
    Kilmarnock, VA
    There is little need to have a yoke created for your application.

    Use the two top 10M rigging points and mount a pair of O clamps to them. You can then directly mount the 450's to a truss. If you need swivel capabilities, use a short length of pipe between the O clamps with a 1/2" hole drilled in the middle to which you mount another O or C clamp.

    If you're set on the yoke idea, feel free to contact me and I'll have our machine shop work up a price.
     
  7. museav

    museav CBMod CB Mods Departed Member

    Messages:
    4,017
    Likes Received:
    562
    Occupation:
    Acoustical, audio and audiovisual consultant
    Location:
    Marietta, GA
    Just to clarify what may be confusing, ATM Flyware and Allen Products are both part of Adaptive Technologies. Basically, two companies now under one common corporate structure. Allen Products tends to focus more on hard mounts while ATM focuses on rigging.
     
  8. jkowtko

    jkowtko Active Member

    Messages:
    806
    Likes Received:
    50
    Location:
    Redwood City, CA
    This sounds easy enough -- my concern was if a 20 degree downward tilt would put too much strain on those m-10 bolts. Our lighting guy says this is routine for light mounting and for a 50lb speaker even clamped at a 45 degree down angle shouldn't be an issue ... if you think this is okay, then it should work for me (I don't need swivel necessarily because we'll have the truss pipe oriented correctly to begin with.) I'd prefer not to have to tether the botom of the speaker if possible.

    Thanks. John
     
  9. BillESC

    BillESC Well-Known Member Premium Member

    Messages:
    2,321
    Likes Received:
    356
    Location:
    Kilmarnock, VA
    John,

    The O clamps are rated for 220# each. We've hung hundred pound moving heads at a 45 degree angle without problem.

    Always safety overhead fixtures and speakers.
     
  10. jkowtko

    jkowtko Active Member

    Messages:
    806
    Likes Received:
    50
    Location:
    Redwood City, CA
    Okay, for lack of funds I ended up making a three-point fly mounting hanger out of a triangular piece of 3/4" plywood with 5/16" turned eyebolts bolted in at the appropriate hanging points. The plywood hanger can be mounted on just about anything at the COG. Right now I have on speaker wall-mounted using the standard On-Stage wall mount bracket. I just drilled a 1 3/8" hold in the plywood hanger and slid it onto the wall mount post. Now my speaker is pretty much fully adjustable -- yaw, pitch, and roll.

    (And, yes, I have two safety cables per speaker ....)
     
  11. museav

    museav CBMod CB Mods Departed Member

    Messages:
    4,017
    Likes Received:
    562
    Occupation:
    Acoustical, audio and audiovisual consultant
    Location:
    Marietta, GA
    I am not a rigger, but I know that you should be using forged shoulder bolts oriented in the proper direction and not turned eyebolts, which can bend or pull open. The fact that you used turned eyebolts also makes me curious about several other issues such as what reinforcing there is where the eyebolts mount to the plywood (is there a metal plate or at least large washers to help spread out the load and prevent the eyebolt from pulling out?), what reinforcing there is around the hole where the wall mount comes through the plywood and how do you lock the plywood mount to the wall mount post to keep it from twisting and turning, what hardware you used for adjustability, etc.
     
  12. jkowtko

    jkowtko Active Member

    Messages:
    806
    Likes Received:
    50
    Location:
    Redwood City, CA
    The 5/16" turned eyebolts have approx 100lb working load with a 4:1 safety factor. The speaker is 50 lbs, so at most each of the two main rigging points will take 25lbs of load. Eyebolts are through the plywood with a fender washer, regular nut, and jam nut. The bolt is also a couple inches longer than required so if anything started to come loose I would notice it well before a nut had the chance to workitself off the bolt.

    I use regular welded link chain instead of cable, so I can adjust length easily. The M10 bolts I am using for the speaker aren't forged eyebolts, but for now I just put the bolt thru the last link in the chain, with a washer on top, and screw the bolt in until it's tight. I use a 30mm bolt so it has a full 20mm of thread into the speaker. Again, it would take a lot of turning to have a bolt come out. And the M10 heads are taking at most 25lbs of pull so the heads aren't going to pop off anything soon. I'll eventually replace these with forged eyebolts once I find the eyebolts at a decent price.

    I've had the center cluster rigged using this hardware for the past two years and haven't noticed any bending or movement whatsoever. But remember, these are just 50lb speakers, not heavy plywood cabinets. For anything over 100lbs I would probably beef this up considerably.

    The plywood itself is set on on the wall mount bracket. The bracket has a 1 3/8" x 4"standard speaker mounting post. I simply cut a hole in the plywood at the approx COG, doubling up the plywood around the hole for reinforcement, and slipped it onto the post. It is not fastened, but it's a reasonably tight fit, so with a speaker hanging from it there is no chance that it will ever ride 4" up the post and slip off.

    My biggest concern, frankly, is that the wall mount bracket will somehow break loose from the wall. These brackets have only two 3/8" lag bolt mount points, and the top bolt is taking the bulk of the load. But this looks like the weakest point in this structure, and if the wall bracket is rated at 60-100lbs (and assuming there is a safety factor built in) then I think I'm in pretty good shape.
     
  13. Andy_Leviss

    Andy_Leviss Active Member Premium Member

    Messages:
    473
    Likes Received:
    19
    Location:
    NYC

    No, no, no. You MUST use properly rated hardware, used for a purpose it was designed. This, I'm fairly sure, is neither. Safeties or not, use the appropriate hardware, or don't rig it.
     
  14. avkid

    avkid Not a New User Fight Leukemia

    Messages:
    5,948
    Likes Received:
    225
    Occupation:
    Stageline Operator/Staging Supervisor
    Location:
    Howell, NJ
    Time for me to put on the loudspeaker salesman hat.
    -
    Andy is right, period.
    If it isn't rated, it doesn't fly.
    -
    If you think the manufacturer will honor the warranty when you pull stuff like this you are sorely mistaken.
    -
    There is a reason manufacturers standardize(somewhat) the placement and type of rigging points.
    It makes it easier to "do it right" instead of "git 'er done".
    -
    :!:YOUR LIFE DEPENDS ON IT.:!:
     
  15. museav

    museav CBMod CB Mods Departed Member

    Messages:
    4,017
    Likes Received:
    562
    Occupation:
    Acoustical, audio and audiovisual consultant
    Location:
    Marietta, GA
    Using just this one point as an example, consider that the 100lbs. working load you noted is probably based on straight pull and just under a 100lbs. straight pull working load does seem common for typical 5/16" turned eyebolts. However, it is almost certain that in many instances your loads are not straight pulls, the cable will be coming in at some angle. At a 45 degree pull the working load might actually be 25-30% that of a straight pull while at a 90 degree angle as might occur in a pullback, it could be 25% or less.

    In comparison, the eyebolts offered by Mackie, Polar Focus, ATM and others for use with the SRM450 are all forged shoulder bolts (M10 x 1.5mm x 17-20mm) with a straight pull working load of over 500 lbs. So apparently what you used is not what is recommended by the manufacturer and others for your speaker, including having a working load less than 1/5 of that of the hardware recommended. And even a Mackie SRM450 falling can seriously hurt someone.
     
  16. jkowtko

    jkowtko Active Member

    Messages:
    806
    Likes Received:
    50
    Location:
    Redwood City, CA
    Okay, I get the hint. I found some forged M10 eyebolts at a good price so I'm picking up a bunch of them to swap in.

    I am a mechanical engineer by training, though, so I know the forces involved, and I would argue that my three-point fly rig is actually safer and puts a lot less strain on the hardware than the two-point rig that Polar Focus sells. (If someone wants an explanation of this I can send in a separate email).

    But, sure, a welded or forged eyebolt is going to be stronger than a turned one, and even though the current bolts are at least 4x the capacity of the speaker weight, there's nothing to say that some freak accident will result in someone jumping to the speaker to save themselves ...! In those cases a 500lb capacity will definitely help. Likely? No ... but freak accidents do occur.

    Unfortunately, in this case the On-Stage wall mount bracket is the weakest point in the rig. With a 100lb rated capacity it is only 2x the speaker weight. I've already gotten a quote from a local metalworks for $200-300 to weld up much beefier wall mounts ... once I can scrounge up the budget I will get them. In the meantime if anyone wants to support the cause, I know my theater will gladly take donations :)

    Thanks. John
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice