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Blog  > What I Have Learned  > Nelson Mandela Bay Stadium Project

09 June 2016

Taking down 56 speakers weighing 70kg each, suspended 34 metres from the ground to then test, fix where needed and then put back in place, took a crew of five 22 days to do. 

We initially installed the main PA system at Nelson Mandela Bay Stadium in 2009, a mammoth job to say the least.  Annually we carry out annual rigging maintenance – which was done in last month.  What an insight for me! 

 

 

 

The rigging system consists of:

  • A safety chain, a wire or chain which is attached to the speaker on a different point from the bracket so if the speaker were to fall, the safety chain would prevent damage to the unit or the audience
  • A bracket, which were all replaced due to weather damage. Speaking with our installations team leader Martin Pain, he told me: “It’s a huge job, but really exciting to work on.” 

To get the speaker down from the stadium roof,  the crew opens the speaker inspection hatch to attach a sling and safety ropes. They are literally hanging from the roof, much like you see in action movies where the SWAT team descends from a roof to bust the baddies! The guys then loosen the bolts, disconnect the safety chain and speaker connections for the ground crew to then literally lower the speaker using pulleys and a grigri (an assisted braking delay device).  

Once the speaker’s on terra firma, the crew clean and test the speaker. Martin summed it up in a nutshell: “We have a sound desk and amplifier to wire in the amp cables and play music to the speaker. We can then determine whether all the drivers (tweeters and sub driver) are working. If there is no music, then we start stripping the speaker to find if it is the crossover (a crossover is a device that takes a single input signal and creates two or three output signals consisting of high-, mid-, and low-range frequencies), or if something has blown.” Of course, I now know what all that terminology means! 

So it’s a huge job and one our team looks forward to annually.  I think they may enjoy the adrenalin rush too!

The system has been well looked after and the stadium falcon helps prevent other birds nesting in the speakers and damaging them. Coupled with this, as the operators of the sound system, we always ensure the system isn’t pushed to the limits. 

Let’s take a look at the project in numbers:

  • 3 hours to take down, test, fix and re-hang each speaker
  • The 56 speakers, including the brackets weighs around 3,920kg
  • It only takes one person to lower a speaker, but three strong (make that super strong) guys to raise it.
  • For every three metres the ground crew walked to hoist the speaker up, the speaker goes up a one metre
  • The sound system delivers in excess off 45,000 watts at high SPL level. SPL stands for Sound Pressure Level, also referred to as efficiency and sensitivity. This parameter represents how loud a speaker is. A high SPL equates to a louder speaker. 

I’ve been here a year, and no one day is the same, one day the guys are hanging from a stadium roof, the next they’re working on an award ceremony or an international concert.  Life in the tech game!

 

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