Thursday, April 29, 2021

No single point of failure

 We have a philosophy that there should be no single point of failure for our shows. This applies to people as well as tech, but this document is going to concentrate on the tech. For people it means we both know how to do everything that needs to be done and every item in the main set of tech is light enough for either of us to carry unassisted.

With tech, when we say no single point of failure, we mean that if any single item gets broken or fails we have a workable solution that will allow the show to continue. This doesn’t necessarily mean a direct replacement, it means we have something else that can substitute for the broken item and we know how to apply it. It is acceptable that the replacement is not as good or as easy to use as long as it lets us present the show.

It also doesn’t mean that we necessarily have to have replacements for more than one item failing. If two unrelated items fail & we have a replacement for each of them then the chances are good we’re OK but if we allow for any number of items needing replacement we would ultimately need an infinite number of replacement items sitting around gathering dust which, given Earth’s finite supply of dust, is impossible to achieve.

Let’s take a look at a concrete example. When we did our first shows in 2018 we had one speaker and one wireless mic that went straight into our only speaker. When the mic got damaged we needed to buy a wired mic. Next step we had a single pair of handheld wireless mics & a pair of body packs. The receiver of this pair was wired into the input of the speaker. Then we got a second speaker but could only use one speaker at a time. We got a mixer & could drive both speakers. At this point we had cobbled together something resembling a sound system.

If either mic stopped working we had the other. If the microphone receiver went out we could in theory use our wired mic into the mixer. If the mixer went out we could direct wire from the receiver to one of the speakers and if one of the speakers went out we had the other. We’d achieved redundancy which would have been close to the capacity of the full system.

Next up we bought a complete sound system. Wired mics  we’ve never used & swing arm style mic stands we’ve never used either, a 4 mic mixer, speaker stands & a pair of speakers. The existing pair of wireless mics & this system are the direct ancestor of our current sound system. By this time we had developed a slightly less formal version of our no single point of failure philosophy so we kept the older system.

First up we were planning to use our body packs for an early version of The Bunny’s Tale and handheld mics weren’t an option for the play so we bought a second set of mics. We now had full redundancy across the system mics, receiver, mixer, speakers. The revised version of The Bunny’s Tale had 4 actors, each with a bodypack mic. If any went out there was no longer redundancy so we bought a cheap pair + receiver. This caused a potential problem that our mixer only took 4 mic inputs + line. Line would have worked if ever needed, but it was going to add complexity to setup. We eventually bought a slightly larger version of the same thing that takes 6 mics + line so we could have a body pack each and two spare body packs live & plugged into the mixer.

Then we realised that the speakers are too heavy for Tessa to pack in easily so we bought some lighter ones.

At this point the remnants of our original system became unneeded for backup. As it happened, we kept the speakers because they can run off batteries which ability we occasionally have used & the mixer because it has more capability than our day-to-day mixer & it would be worth very little if we sold it off.

As we didn’t start with something very simple, the process with stage lights was shorter. We had a clear image of what we wanted to achieve and the shows we wanted to support. At the same time as we bought the lighter speakers we also bought lighter light stands. Since then we have acquired a simpler, lighter & cheaper lighting set that we can leave permanently set up on the par bar. 

When setting up a show we don’t necessarily use the “best” kit, but whatever we need for the venue / show. Typically we’ve used the 4 input mixer & the lighter speakers, and for the last 6 months or so a lighter set of lights than our full show ones. Faster set-up and less expensive components at risk count for a lot.

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