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[Tim McCulloch]

If you actually read your history you should know that no engineers ever signed off on the KC Hyatt foot bridge (the steel contractor just changed it w/o checking) and the O rings for the space shuttle (read up on Feynman's involvement in the Challenger commission and how NASA management speciflly over ruled Thikol (sp?) engineers objections to launching Challenger in the weather they did.)

I have no knowledge of the rest.

Philip

I was A1 for a major aviation/aerospace safety conference that focused on engineering/professional ethics. The role Thiokol engineer Roger Boisjoly (among others) played in trying to STOP the Challenger from flying that fateful day was a major part of one presentation.  His decision to blow the whistle on Thiokol and NASA cost him his job, career, and life as he knew it.  He would spend the next 26 years talking about professional ethics to anyone who would listen.  Although aimed at rocket scientists and other high-functioning professionals, Roger's lessons apply throughout all business and industry.

Roger passed away this January, 3 months after that conference.

More here:  https://www.nytimes.com/2012/02/04/us/roger-boisjoly-73-dies-warned-of-shuttle-danger.html?_r=1

So Jim is right, someone, somewhere (in this case, Thiokol management in Utah) signed off, corporate officers whose jobs were on the line if the Challenger didn't take off.  Seventy three seconds into the launch, Mr. Boisjoly's worst fears and predictions were proven correct.

RIP, Roger.  Ultimately you made a difference.

Philip, you're also very correct about the Hyatt Regency (Kansas City) tragedy.  The contractor made unapproved changes to accommodate materials (suspension rods) that were not made to the specified length.  No engineer was ever consulted about this change.  "And here's the new hit song by the Hyatt Regency Sky Walkers, 'Bridge Over Troubled Waiters'."

Both of these 100% PREVENTABLE disasters occurred because someone, somewhere, thought they knew better than they actually did.  I will not repeat that mistake; I like to sleep at night.

(edits to fix spelling)

[duane massey]

I will only note that following local codes/practices may or may not be the safest way to hang speakers and lights. In 75% of the work I currently do there are no inspectors, codes, or practices, and hiring a structural engineer or any other certified expert would never happen. It is important to me to keep up with proper techniques and standards, as I have to make decisions that I am confident in. These forums and discussions are invaluable to me, BUT I absolutely understand that giving specific advice on a specific installation wold be very risky for both parties.
Even in a major market such as Houston I have rarely seen any actual documentation for rigging in most clubs and restaurants, and typically only in new construction in churches and schools.
Other areas of the country are not quite so "wild west" or unregulated as my world in Texas and Louisiana. Regardless, if I can't do the work correctly I will (and have) walked away from the work.

[Jim McKeveny]

It is what makes for a horse race. We will never agree on this one.

I do, however, encourage all of you to call your insurance providers and ask them if they believe you have purchased enough coverage.

 

[Ryan Hargis]

I do, however, encourage all of you to call your insurance providers and ask them if they believe you have purchased enough coverage.

That's like a rental company calling their speaker rep and asking if they've bought enough gear.

[Ray Aberle]

That's like a rental company calling their speaker rep and asking if they've bought enough gear.

... to which the answer is always, "No! Here's some new ones you MUST have!"

Insurance agents generally sell you what you ask for... they may inquire as to what your business entails, but only you know what exactly you do that might need coverage, which is why you have to be as forthcoming as possible to ensure you have appropriate coverage. If you screw up, and don't order enough insurance, you can lose money if a claim comes up. If your agent screws up, and doesn't do something, they have an Errors and Omissions policy to cover them.

So, I can understand the level of caution that people use when it comes to rigging... because if you screw up, people can die, and the blame will be placed on the person who signed off on the rigging. This specific example, whereas it appears to be very straightforward, is based on a certain set of circumstances. If a lesser-informed person walked across this forum, and realized, "Hey, I was planning on doing this too, here's how I do it!" and was working with a support structure that could NOT support the weight... well, then there's a problem.

I don't fault anyone for wanting to spend extra time to make sure it's done right. There are a set list of considerations and calculations that MUST be taken into account, each and every time-- it's the lackadaisical attitude of "I've done this a million times," or "it's clearly really easy," and for one reason or another not performing every step correctly that causes trouble. Hence the reason things like electrical is "connect ground first, disconnect ground last." Every time. Without fail.

Ray

(PS: I know very little about rigging. When I was getting ready to fly just two VRX cabinets from a Stageline last year, it was like pulling teeth just to find out what supplies I needed, let alone anything regarding the actual procedure, even though I wasn't going to physically do the work my self. It's not that the fine people on here didn't want to help me; in fact, quite the opposite. They just wanted to make sure I was going about things in the right way.)

[Nick Enright]

Both of these 100% PREVENTABLE disasters occurred because someone, somewhere, thought they knew better than they actually did.  I will not repeat that mistake; I like to sleep at night.

yep, and that's the crux of the biscuit. There's nothing like trying to spin a change made by sales/shop floor/etc..  w/o consulting the engineer(s), I've been forced to twice, after that I got a very bad name in my company, because I would not "play nice" and compromise my professional ethics. I once lost a very good promotion due to it, and was asked: "why are all metallurgists are so honest, it's just data"

When I recieved my BS in Metallurgical Engineering/Materials Science in 1998 I joined the organization below, by choice. I hold to this commitment, even when it's cost me dearly in promotions, cash, job offers, or personal friendships.

http://www.order-of-the-engineer.org/

[Ray Aberle]

yep, and that's the crux of the biscuit. There's nothing like trying to spin a change made by sales/shop floor/etc..  w/o consulting the engineer(s), I've been forced to twice, after that I got a very bad name in my company, because I would not "play nice" and compromise my professional ethics. I once lost a very good promotion due to it, and was asked: "why are all metallurgists are so honest, it's just data"

When I recieved my BS in Metallurgical Engineering/Materials Science in 1998 I joined the organization below, by choice. I hold to this commitment, even when it's cost me dearly in promotions, cash, job offers, or personal friendships.

http://www.order-of-the-engineer.org/

A guy I worked with in the past at the day job once told me, "Integrity is doing the right thing when nobody is looking." I've stuck with that principle, and use that to help me make the right choices.

Ray

[Jim McKeveny]

THIS WILL BE MY LAST ENTRY ON THIS SUBJECT!

Most of the big manufacturers, including JBL, publish handbooks regarding installation. I believe JBL's is titled "Principles for Installing Loudspeakers". These manuals include great information, illustration, & links so that contractors can safely install their products. There are advisories for when to call in deeper professional help.

With this information (consumed by a sentient human being), safely hanging a pair of VRX932's is no more dangerous or difficult than changing a flat tire.....But, from the tone of this thread, maybe that too requires a team of experts.

[Ray Aberle]

THIS WILL BE MY LAST ENTRY ON THIS SUBJECT!

Most of the big manufacturers, including JBL, publish handbooks regarding installation. I believe JBL's is titled "Principles for Installing Loudspeakers". These manuals include great information, illustration, & links so that contractors can safely install their products. There are advisories for when to call in deeper professional help.

Yes, mainly where it says, among other things: "All rated load values, unless otherwise noted, are for in-line-pull—along the centerline of the item. It is the responsibility of the installer to inspect and determine the actual condition of the equipment used, and to incorporate design factors appropriate to the local job conditions."

It goes on to mention that that guide is for informational purposes only, and to state "None of the information contained here us intended as a representation or warranty on the part of JBL. Anyone making use of this information assumes al liability arising from such use."

With this information (consumed by a sentient human being), safely hanging a pair of VRX932's is no more dangerous or difficult than changing a flat tire.....But, from the tone of this thread, maybe that too requires a team of experts.

Could I do so safely on my own? Probably. Would I perform an installation without an expert's guidance? Of course not. Why take the risk that I miss or overlook something? The original poster looks to know what he's doing, and is going to have it done right. BUT, we do NOT want an average user stumbling upon this, doing it themselves, miss something critical, and have it fail.

I guess I don't think you understand or agree with this, and that scares me.

Ray

[Nick Enright]

no more dangerous or difficult than changing a flat tire.....But, from the tone of this thread, maybe that too requires a team of experts

The only reason changing a tire doesn't require a team of experts is because a team of experts came up with a design that is almost easy enough that most anyone can do it.

On the other hand people can't be expected to keep enough air in their tires, let alone properly understand why you torque lugnuts, or what is actually happening at the hub/wheel interface. That's why four lugs is a minimum, when two would be enough for most applications.

[ProSoundWeb Community]