Sound Reinforcement Basics – Setting Up PA

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This is the first in a series of posts about basics in setting up your PA or audio system to give you optimum sound reinforcement for a gig or worship event.  I’m targeting this toward a temporary set up & tear down situation rather than a permanent install, but many of the basics still apply.

The first thing to consider is what size venue you need to support and how much amplification you need.  I have setup mobile systems in a lot of different spaces and the venue has a huge impact on how much reinforcement is needed.  For small rooms with just a guitar and some vocals, 1 PA speaker and a mixer may be all that’s necessary.  A larger space and a full band might only require vocal mics and guitar or keyboard in the mixer.  Drums, bass, electric guitar, etc. don’t always have to be mic’d.

If you are in a large space, let’s say more than 100 people, consider running everyone through the mixer (as long as you have the inputs) so that you have the most control over the mix.  I saw a band play in a big hotel ballroom and the bass player had this huge 6×10 cabinet and head system.  He was rattling the windows and the two little PA speakers the rest of the band was using couldn’t compete.  It was distracting, didn’t sound good, and hardly anyone danced on the dance floor nearby.  That’s the thing…no matter what your occasion, be it worship or entertainment, bad sound distracts from the purpose of the event.  If you have good sound and pleasant mixing, people don’t notice specific things and they are able to enjoy, or pray, or dance.  That’s what we are trying to accomplish here!

To sub or not to sub?  Bass subs are great, but expensive.  If you have a bass player with enough of an amp (within reason) then you really don’t need a sub.  A pair of 12″ or 15″ speakers can handle a lot of the low end.  If you are fortunate enough to have 1-2 subs in your setup, then pair them with 10″ speakers which will keep your vocals and instruments clean.

Powered or unpowered speakers?  For mobile setups, I’m a big fan of powered speakers.  If one dies, all isn’t lost, but if while running an amp and passive speakers the amp goes out, it’s all over.   For permanent set ups it’s often better to go with passive speakers where you don’t have to run power cords all over and volume can be controlled from the amp which is hopefully located conveniently near the mixer.  I have purchased and referred several people toward Alto active speakers.  They’ve been a terrific value for monitors and mains.  I really like QSC’s, but they can be out of many budgets.  I don’t currently own any subs, but would eventually like to have 1-2 in the arsenal.  It’s tough to get that punch in the chest kick drum sound from just PA speakers.  For most mobile setups though, subs aren’t critical.  If you’re in a more serious space or have a need for that next level, there’s probably a sound system hard wired that you have access to plugging into (but don’t count on it).

Finally, the physical arrangement is just as critical as the planning.  The biggest advice I can offer is to place your speakers at the front of your band rather than behind.  There are all kinds of scientific reasons behind it, but trust me, speakers at the front plane of your ensemble will prevent feedback from happening so easily.  If speakers have to be behind, put them up high.  The biggest cause of feedback and muddiness is having  sound cycle back through the microphones.  Should speakers be close to you facing out or at the edges facing in?  I’m sure there is debate on that.  It depends on the space really and how long your cables will reach.  Seems to me that keeping the main speakers tight to your group facing out is cleaner and avoids phasing where sounds get muffled or thin because the speakers  are overlapping frequencies over the same coverage area.  It also feels more natural when the amplification is closer to the sound source.  If your speakers are farther out, you might consider running the mix in stereo and panning to help reduce phasing.

That’s enough for this article.  We’ll get into how your mixing board works in the next post.