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Preparing Your PA For Outdoor Gigging

Live Sound Advice
By Mike Crofts

PA outdoors

The season of open-air shows is upon us — but is your gear really ready for the great outdoors?

Spring is finally here, Summer is just around the corner, and the great warm sunny outdoor live-sound season is nearly here — which means it's time to get to grips with the preparation and minor maintenance that I've been putting off since, well, last October. I aim to meet this year's open-air challenges with as much confidence in my gear as possible, always hoping for the best but planning for the worst; even the best of sound equipment can go wrong, but I need to know I've done everything possible to ensure things run smoothly. My approach to making sure everything is ready to roll is the same as when I'm prepping for any live gig or loading the van: my checklist follows the whole PA system from start to finish, stage to speakers, following the signal path and checking that I have all the component parts from microphones (and stands) through cables right through to the speakers (and stands) and monitors. Of course, a maintenance check includes all the gear, not just a single rig chosen for one event, and it's at this time I take the opportunity to update my inventory and list all the bits and pieces that I seem to have acquired throughout the year.

I suppose it's also a good opportunity to consider which bits of kit I haven't used in the last 12 months (or longer) and think about moving it on to make more space and raise a bit of cash. In checking all the gear I try to include absolutely everything and set aside four or five days for the task, but the smaller items that are used on the stage tend to receive the most physical abuse, so I probably spend more time checking them out in detail. The golden rule is to always take a good criticallook at any electrical and electronic gear, whatever it is, before you switch it on — if there are any signs of damage or dampness, don't even plug it into a power source until it's thoroughly dry and clean.

Mic Time

Although my gear is stored, tagged and used in three categories — live sound, recording and lending — I include everything in my testing and maintenance. I don't do dry hire, but I occasionally lend things to friends/ex-friends, and experience has taught me that such items really need to be those that aren't essential to my operation!

Before (left) and after (right) repair: dented mic baskets can be easily repaired with the help of a round-ended broom handle.Before (left) and after (right) repair: dented mic baskets can be easily repaired with the help of a round-ended broom handle.

I begin with the microphone stock. The mics most likely to have issues are the live stage set, and I'll do a quick functional check before anything else — after all, if the capsule is damaged there's not much point in spending time polishing the case. I haul out all the mics, plug several in at a time, and speak into them while listening through the studio PA so that I can compare them directly within their make and model group. This way I can pick up minor differences in performance that I might otherwise miss, and which can cause problems during a soundcheck or can herald a more serious failure in the near future. As an example, this week I tested a batch of eight vocal condensers, which are part of my backup/second stage set. I thought they were all perfectly OK, but I discovered that two of them sounded distinctly 'choked', so they are now in the spares bin.

Once the functional check is done (including giving the mics a good shake to discover loose components, and checking that any switches operate reliably and quietly), I'll attend to the mechanical and cosmetic side. I remove the wire baskets (these almost always simply unscrew), and clean out any detritus that has accumulated in there. If it's possible to remove the foam liner it's a good idea to take it out and gently wash it. This is more important for hand-held vocal mics, for obvious reasons, as after a year or so of heavy use they can start to smell less than fresh. If the foam is beginning to disintegrate it's an easy enough job to replace it altogether, either with some acoustic foamof similar thickness and density, or by simply buying a new basket assembly.

Although it doesn't really affect the sound, wire baskets on SM58-type mics are easily flattened on one side if dropped, and it's possible to push these out to make them look better. My method is to use a wooden broom handle with a rounded end. Stand the broom handle upright on the floor with the rounded end up, put the mic basket over this end, and gently coax it into shape from the outside with a rubber or wooden mallet.

A toothbrush is ideal for cleaning the mesh itself, and stubborn lipstick residue yields to a trace of washing-up liquid in warm water. At the other end of the mic body, I check that the output pins are all straight and firmly anchored, and that their plastic base is screwed tightly into the mic casing — these are usually secured with tiny grub or countersunk screws, which can easily rattle loose and fall out, so it's a good idea to put a drop of nail varnish on the thread and re-tighten. Lastly, I spray a very small amount of switch cleaner/lubricant onto the output pins and plug and unplug a known 'good' XLR a couple of times to clean and protect the metal surface. A plain switch cleaner such as isopropyl alcohol will clean but not protect the contact, so a cleaner/lubricant is best — but use it as sparingly as possible.

I also check that my wireless mics all work in sets without interference, as over the course of an outdoor season the frequencies can get changed to accommodate other radio equipment. I will also make sure that my stock of batteries is suitable and well inside its shelf life.

Stand Up

Next in line after the microphones are the stands they sit on, and over the course of an outdoor season these probably sustain more rough treatment than anything else in the kit list. As with mics, damage and wear can be both functional and cosmetic, and the most vulnerable parts are the various adjustment screws and clamps. The metal castings — usually the base that anchors the folding legs and the head where the boom part meets the upright part — are made of a soft alloy, and the internal threads are easily stripped. This doesn't necessarily mean that the stand is scrap, however, and I've saved quite a few over the years by purchasing oversize threaded screws and re-tapping the stripped thread. I carry a bag of spare screws and a tap in my toolkit, and it takes about one minute to complete an effective and permanent repair at negligible cost — it's often possible to re-tap without even drilling a new clearance hole.

If the re-threaded part of a boom stand strips again, all is still not lost, as the top of the upright stand has a 3/8-inch male thread that, having removed the boom altogether, will fit straight into a mic clip, so you'll still have a straight mic stand left, as well as a really useful piece of metal tube to put with all the others.

Cosmetically, black-painted stands get quite unsightly when the paint becomes chipped, and I occasionally repaint the base casting in matte black, as it doesn't show up blemishes and covers well. For chrome stands that have become mildly pitted or have surface corrosion, I use the old car bumper/bike handlebar trick, which is a handful of kitchen aluminium foil, scrunched up into a ball, dipped in water and rubbed over the chrome surface until it comes up clean and shiny. A final wipe over with a bitof furniture polish on a rag (avoid anything containing silicone) keeps it protected for a while.

DI boxes can present problems if left unchecked for too long. Although they sit on the floor when in use, they are small enough to be kicked around or dropped, and because they are relatively heavy the internal parts can work loose. Definitely look inside the battery compartment and check the input and output jack sockets, which are more likely to work loose than the XLR output. Now is also a good time to remove any old labels and pieces of tape, which tend to get stuck on during gigs and which no-one ever seems to get around to taking off afterwards. If they are left too long they will probably take off paint and lettering when removed, and also leave behind a nasty sticky residue — I find this is best removed with a bit of penetrating maintenance spray such as WD40 or similar.

Taking The Lead

Next in the audio path are the mic cables, and as they all reside in one trunk I look at all my cables together. This is a time-consuming job, repetitive and boring, and, if you are lucky enough to have an assistant or helper, this is the one to delegate. That's not to say it's unimportant — far from it, because the cables are far more likely to exhibit signs of damage than anything else and are easily replaced on the job, until one day you find you've used your spares and are the proud owner of a box full of 'suspects'. I use a cable checker for functional checks, which is an inexpensive and time-saving tool, and which can discover unseen faults such as one side of a balanced cable becoming disconnected. Depending on the connected gear, the cable may still work, but with a signal-level drop that can be difficult to trace. A physical check is a good idea too, not to the extent of looking inside every connector but checking that cable grip screws are in place and connector covers are tight and undamaged. I've also developed a habit of running cables through my fingers as I coil/uncoil them at gigs, so I can feel any damage to the outer covering.

Faulty cables can sometimes appear to be functioning correctly on some items of equipment, but will fail completely on others, so it's worth getting a tester and going through your cables before you take them out to a gig.Faulty cables can sometimes appear to be functioning correctly on some items of equipment, but will fail completely on others, so it's worth getting a tester and going through your cables before you take them out to a gig.

As well as signal cables, the mains leads need to be checked too, and may require electrical safety testing. I don't test all my cables at the same time because if, for some reason, I didn't meet the 'next test due' date then they would all be out of date.

Although portable appliance testing (PAT) isn't a legal requirement in the UK, safety management is, and this is a relatively easy way to demonstrate commitment and compliance with your own safety policy. With that in mind, and as I do my own testing, I make sure that my tester is calibrated at the start of the year when everything is quieter. If I contracted the testing out, I'd be inclined to have everything done on the same day as it would be more efficient and probably cheaper. It's not really enough to just stick a green test label on a piece of equipment saying 'passed', and a proper inventory record should be kept. When I test mains leads, for example, I write the earth connection resistance reading (eg. '0.03') on the label itself so that I can see if it's changed next time I test it, and if necessary I can then investigate any changes which may indicate internal deterioration.

A physical inspection of mains leads is essential, and I always include distribution blocks and extension reels. It's well worth running out cable reels and checking for cuts and damage along the entire length, because winding up long cables after a gig is often left to someone else, perhaps a casual helper who won't be around next time and who won't be looking too hard for problems. Heavier power cables with 16/32A connectors and power distros need to be checked by a qualified electrician, and you may be able to take these along to a local contractor who will check them out while you wait — again, not something you want to leave until the last minute. In these digital days, don't forget to check any Cat 5 cables, as these are commonly made from single-strand conductors that can break after a few coilings-up, and the plastic latch tabs on the plugs are prone to breaking off. Mounting the connectors inside metal housings such as those made by Neutrik will provide much longer service and a more reliable connection, and will impress your clients no end.

Mixer Fixer

Moving on to the major parts of the system, there's probably less to check as these tend tobe fixed in place during a performance and are generally transported in their own individual cases. The only maintenance usually required for mixers is to check for smooth and noiseless operation of linear and rotary faders, and connect a source to all the inputs in turn to check for damaged, dirty or loose connections. I've found that using any kind of 'maintenance spray' on fader tracks invariably makes them worse, and my recommended method is to simply work noisy faders through their full travel several times (they have a self-cleaning action) or use an air spray to shift any junk that has found its way through the slot. XLR inputs are not prone to problems, provided that the whole connector is securely mounted, but it's as well to check the insert and line jacks carefully; I spray switch cleaner/lubricant on a stereo jack plug (not through the hole) and push it in and out of each socket a few times, which cleans the contacts inside and leaves a protective film in place.

Use the right treatment for the job! Contact cleaners with lubricant will both remove and protect against oxidised contacts, while a water-displacing spray like WD40 can help remove sticky gaffer-tape and label residues.Use the right treatment for the job! Contact cleaners with lubricant will both remove and protect against oxidised contacts, while a water-displacing spray like WD40 can help remove sticky gaffer-tape and label residues.

Some mixers make much use of internal ribbon cables with multi-way connectors to connect between circuit boards, and these can cause problems; a full functional check will hopefully show that all is well within, but if necessary it's easy enough to open the case if you have suitable training or experience in electronics work (otherwise call on professional support). Tell-tale signs of poor internal connections include noise being generated when the mixer case is tapped or moved, and another clue is meter indications that don't seem to relate exactly to the signal being monitored, or uneven display levels. Put a mono signal through and make sure left and right meters show exactly the same level as both channel and master faders are moved through their full range. For digital mixers there isn't much the user can do inside, but I will at least check that I'm running the latest firmware, and also do a compatibility test with any new USB memory sticks I intent to use for scene storage or live recording.

Outboard gear gets the same treatment as the mixer — ie. controls, connectors and metering — and a full check to make sure it actually still works like it used to!

Full Backing

Playback devices are vital things at so many gigs, especially community events where different performing groups may produce backing tracks or intro music on a variety of formats, so checking my CD decks and making sure I have all the leads and adaptors needed to patch in from personal cassette players, mobile phones and such is time very well spent. The main problems I've encountered with CD players is not so much the electronics but the loading mechanism, especially those rubber grab rollers which eat anything you offer up to the loading slot. Getting at these is not easy, especially with consumer-grade decks, and I made myself a cleaning disc which has worked well and got me out of trouble a couple of times — for emergency use only though, I should add! When you buy a 'cake' of blank CDs or DVDs, there is usually a solid plastic disc on the top and bottom of the pile, and I took one of these and roughened up both surfaces with some coarse abrasive cloth and scored a few lines across it until it felt quite rough and 'grabby'. Offering this up to the slot but keeping hold of it while the rubber wheels try to pull it inside can take the glaze off them and restore their grip if they're not too badly worn. Don't be tempted to use a real CD for this, as the silver surface or printing can come off in small particles if you scratch it, and will do more harm than good inside your deck. The proper solution is to dismantle the deck and clean the rubber rollers with isopropyl alcohol, as in the days of reel-to-reel tape recorders.

This is the point where I check that all my various adaptors and specially made-up cables are still present. On an outdoor gig I try to take an 'anything to everything' approach, because you never know what the performers will need.

The Big Stuff

Nearing the business end of the system, power amps and speakers just need a good visual inspection and a gentle run up to full power to check for rattles or other issues. If there are air filters present, I remove and clean them, as after even a few outdoor events they can accumulate a significant amount of grass and dust, and whilst most amps will have in-built protection against overheating, you don't want them shutting down in the middle of the show. It's also worth looking at the actual blades of cooling fans, and cleaning off the dust layer to maintain efficiency.

If speakers have been stored in less than ideal conditionsover the winter they should be brought into a nice warm, dry room and left for a day or so before being used. If it's easy to get inside them it's also a good idea to vacuum out the cabinet and make sure that any acoustic wadding is firmly in place. It's at this point that colonisation by other species will be noticed — and that's why I'm always going on about the benefits of full-face metal grilles that cover all possible entry points! With power amps and self-powered speakers I check that the internal power supplies don't seem to have become noisy and that there's no excessive audio popping or crackling at switch-on. Mains-related noise on the output with no signal running through may be an early warning of a PSU problem, and is best checked out now rather than on gig day.

Flightcases are often the only thing that stands between your expensive gear and disaster, and so are worthy of special attention.Flightcases are often the only thing that stands between your expensive gear and disaster, and so are worthy of special attention.

And while I'm looking at these larger components, I'll take the chance to glue down tears in the vinyl or touch up any paint chips. Scratches and scoring on moulded cabinets can be addressed with fine rubbing-down paper, but personally I avoid using any kind of polish or plastic restorer, as the shinier the surface the more any blemishes will stand out under artificial lighting. I check the tightness of cabinet screws and speaker-mounting bolts, and this is the time to deal with rattles from the grille. In extreme cases, I'll beef up the mounting screws and put a strip of very thin foam behind the grille to isolate it from the cabinet baffle.

Cover Versions

If the gear has covers, they are there to take the knocks of transporting the gear, and will eventually begin to look tired and may not offer the protection required. Some OEM covers are very expensive, so it's worth mending small rips and worn patches before the whole thing starts to come apart. I use gaffer tape only as a last resort though, as it doesn't last long, looks rubbish and eventually decomposes into a sticky mess. Much better is to find a piece of similar material (old holdalls and soft suitcases make great donors) and stick a patch over the damage with contact adhesive (not super-type-glue), which will remain flexible.

Flight cases are our friends, and they deserve a bit of love too. Tighten up those casters, lubricate the annoying squeaky wheels, and check that handles are safe, particularly on heavier items. Leather or rubber strap handles can split apart internally whist still appearing OK from the outside, although replacing these is a real pain as rivets may have to be drilled out and replaced.

As I've reached the end of the signal path I have covered the whole system, including the monitors — and I will try not to forget the speaker stands and poles, as these can cause lots of trouble if not maintained. The main culprits are the little captive nuts and bolts that hold the tripod legs in place; because they act as pivot points when the legs are folded they can easily work loose, and 'tis often said that tripods tend to work best with three legs. My solution (and this is best done pre-emptively) is to loosen the bolts a few turns, apply a drop of paint to the exposed threads (or special thread-lock compound, if you're a posh person or play the viola), and re-tighten to achieve a secure and lasting solution. On the subject of stands, I have a thing about missing feet, and I like to remove them, clean the legs and glue them back on. If they won't come off easily then I probably did them last time.

Having checked right through the rig — including all the spare units and the lending stuff — there are a few other things left to do.Power-distribution units are obviously one of the last things you want failing you at a gig, but these should be checked over by a qualified electrician.Power-distribution units are obviously one of the last things you want failing you at a gig, but these should be checked over by a qualified electrician. The nature of outdoor events is that the weather is always a big factor, and sometimes I seem to load up more tarpaulins, ropes, bin bags and plastic sheeting than sound equipment. Tarps are thankfully cheap to buy, but the really low-cost ones don't last more than a season or two before they start to disintegrate and become very porous, so I have tended to invest in good-quality heavyweight versions. Tarps are not much use without ropes or bungee straps, and for some reason the quantity of these dwindles gig by gig, so I'll check and replenish stocks as necessary, and also make sure my rigging straps are undamaged and the ratchets work smoothly — these can inflict pain if they become partly seized.

I try not to take my own gazebo with me to gigs (better to make sure the organisers provide one), but I always take heavy-duty tent pegs and a lump hammer, as the flimsy hardware usually provided with the inevitable 'family pop-up deluxe gazebo party tent' are far from ideal and about as much use as a cornflake in anything above a gentle breeze. Sound equipment doesn't like strong direct sunshine either (even a relatively short exposure can wipe out LCD screens), and a couple of old sheets take up very little room but provide great shade for mixers and powered speakers (many of which don't have built-in fans) in exposed positions.

Papers Please

Other not-so-obvious things to attend to before the season gets underway are things like paperwork: has the van got insurance and MOT to last right through the Summer? Are all the appropriate insurances and licences in place and current? I write a generic risk assessment to cover my activity, which I then review and adapt to suit each event, and this travels with me along with my public liability insurance and any other compliance paperwork in a folder, which can save me lots of on-site trouble.

Some venues are very strict about electrical safety testing, and increasingly there are noise-related issues so I pack my PAT tester and a sound-level meter, which are both referenced in my generic risk assessment. If I'm taking my back-up generator I make sure it's fuelled up (it will do about nine hours), as many sites won't allow fuel cans or re-fuelling. Smaller or consumable items such as tape (three kinds — gaffer, electrical, and stripey hazard), Sharpies, fuses and torch batteries do eventually become depleted, so I check and replenish the contents of my Special Box that lives underneath the van seat, and which also contains a selection of standard and specially developed tools for field repairs.

Any outdoor event would be a dull affair without humans, and myself and the crew are taken care of with my portable 'people pack', which contains spare work gloves, a couple of hard hats, sun cream and a first aid kit to deal with minor injuries. I also have certain special creams for specific live-sound afflictions such as the dreaded Sweaty Gig Rash. Last, but by no means least (especially for smaller operators), don't forget to arrange any helpers well in advance, as a good assistant makes all the difference between a fun gig and a nightmare — try to get an Elf if you can, as they are great with ropes and don't need feeding.

There's vast numbers of things I haven't mentioned, and of course everyone will have their own priorities according to the rig they run and how they run it, and everyone involved in outdoor live sound will have many more and probably much better tips and tricks than covered here, but in the end it all comes down to two unarguable facts: preparation is great, and it can't be done afterwards.    

Published June 2014