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How To Be A Gear Snob:
Addressing the Public Address
An Introduction to PA Systems
By Corralee Booth |
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Testing, testing, one-two-three… (insert high-pitched feedback
wail here). Ah PA Systems. Is there a foolproof way to plug
in and play? Not really, if there were, sound checks wouldn't exist.
In my opinion, people almost always over do it with PAs. Big huge
bass bins and gigantic towering speakers that not only cause internal
damage to most of your audience, they leave you absolutely no room
to move around on stage and you can't go over half volume without
getting a swat team to shut you down for noise pollution. This article
is my quest for more stage room and to try to get more people comfortable
with doing their own sound.
When I first started in all of this music business, I was terrified
of the monster with tentacle like cables spewing forth from its
back. It took up half of the stage and squealed and roared whenever
I came near my microphone to sing. I didn't know how to set it up,
or work it at all. Over the years I have picked up a few things
to help. [Admittedly mostly through bugging the crap out of sound
guys]. There are some basic concepts to keep in mind: Power,
Watts and Ohms, Speaker and Monitor placement, Equalizing, and Volume
Control. Effects come into play as well, but they will be addressed
in future articles.
Powered And Non-Powered
There are two types of PA mixing boards. Powered and non-powered.
The powered ones are nice because they combine your power amp with
your mixer in one convenient box, which equals fewer parts to carry
and get lost. You just get some speakers to match, plug in and play.
There are a few powered mixers that come all-together in a suitcase
type of a package with mics, speakers and all your appropriate cables
and work very much like a basic home stereo. These are great for
practice PA units and for small venue / coffeehouse type gigs, and
I highly recommend them for beginners or small acoustic type groups.
The non-powered mixing board is a bit trickier, but you don't need
to be scared off by it. You will have to buy a power amp and some
speakers to get sound, but at this point, you can get a mixing board
as fancy as you want or keep it Plain Jane. Some include effects,
some don't, and some have other neat gizmos we will get into later.
You don't need to pay extra for a bunch of stuff you don't need
though, simply decide how many channels you need (how many instruments
or mics need to go through the PA system) and go from there.
Watts and Ohms
Watts and Ohms are probably the most confusing part of setting up
a PA. Your power amp or powered mixing board (the powered amp is
already built into the powered mixing board as I mentioned earlier)
will have a certain Wattage and Ohmage in your owners manual. You
have to get speakers to match this. If you don't, you can possibly
damage both your speakers and your amp.
Most amps are in stereo. So if you buy an amp that is 1000 watts
that means it will have 500 watts per side. (Each side of the stage).
Many of you will not need this much power and some may need more.
As a general rule of thumb, you should get one watt per audience
member. So if you have an amp that can put out 1000 watts RMS (500
per side) then you can have 500 people hear you in stereo. There
are two ways that companies rate their wattage: RMS and peak. Ignore
peak Wattage! Companies stamp that on their amps trying to make
you think that it will handle running at that kind of power and
try to make the amp seem more impressive, but it wont. What is important
is RMS. This is how much power you can put out for a long period
of time and the only wattage you need to be concerned with. So to
recap, Wattage per side RMS equals the amount of people who can
hear you play at a reasonable volume for an entire show.
Ohmage is what kind of speaker configurations your amp will handle.
Your rating (available in your owner's manual) will show whatever
the Wattage and Ohmage is per speaker output. Let's say you buy
an amp with only two outputs for speakers (one per each side of
the stage) and it says that it is 1000 Watts (500 per side) rated
at 8 ohms RMS. Then the easiest thing you can do is to get two speakers
(one for each side of the stage) that are 8 ohms and are rated to
handle 500 watts. If you are a beginner, do not go any further than
that. Keep it simple.
Let's say you're a bit more advanced and want to get a bit trickier
and daisy chain your speakers instead. (One cable runs from the
amp to the first speaker and then a second cable runs from that
speaker to a second speaker) Your power draw divides pretty much
by half, so then you can get four 16 ohm speakers rated for 250
Watts (and up) and link up two per side. Forget regular math, because
Ohms divide by half when you link them up. Two speakers X 16 Ohms
= 8 Ohms.
So to recap once again:
Easy equation. Two X 8 Ohm speakers rated at 500 watts = One power
amp with two speakers (one on each side of the stage) with a rating
of 1000 Watts (500 per side) 8 Ohms RMS.
Tricky equation. Four X 16 Ohm speakers rated at 250 watts (and
up) = One power amp with four speakers (two on each side of the
stage) with a rating of 1000 Watts (500 per side) 8 Ohms RMS.
Most powered amps and mixers have outputs not only for speakers,
but for monitors as well. If it doesn't, remember the rules on wattage
and daisy chaining and proceed appropriately by using one per side
of the daisy chain as your monitors. However, let's say your manual
lets you know that your amp is rated for 1000 watts (500 per side)
8 Ohms RMS and you have speaker outputs and monitor outputs. Here
you can use two 8 Ohm speakers and two 8 Ohm monitors. The monitor
outputs don't affect your speakers because the amp is geared to
handle the appropriate output for each speaker output.
Placement
Our next discussion is where to put these speakers and monitors.
Speakers need to face the audience and they need to be at about
chest level. So if you're doing sound for a bingo, or a sit down
club with no dancing or anything, sit the speakers either on chairs
or shorten your stands to about a sitting level. You can even get
away with sitting them right on the floor if they are big enough.
If there is dancing or standing, you need to get some stands and
get those speakers up off the floor. It's amazing how many people
miss this point. If all of the sound is just heading straight for
the audience's legs, it's going to sound quiet and muffled because
it's not facing anyone's ears. People then proceed to turn up the
music for the audience to hear and it continues to filter through
their legs and go outside to the neighbor's place where they can
no doubt hear it perfectly and call the police to complain about
all the racket. Your sound although louder inside will still be
muffled and yucky by being filtered through moving bodies and bouncing
off walls before it eventually hits your ears. The one exception
to the rule is that if your bass bins are separate from your midrange
to high speakers leave the bass bins on the floor and get the highs
up near the audience's chest. Bass is better when it has contact
with the ground to shake it and help your bass go thump.
Monitors
Monitors need to face you as best as you can. Monitors are
usually the main reason for feedback, so it is important to place
them appropriately. All rooms and situations are different, so I'm
afraid I can't give you a foolproof way to set them up every time.
There are some basic rules though. One, people need to hear themselves
through them. Two, any microphone that directly or indirectly faces
them will feedback. Three, putting your set list on their face can
make them sound muffled and even increase the chances of feedback.
And four, they are almost always a total nuisance if not imperative
to you being able to hear yourself and usually get under your feet
and in your way with all their cables etc. They are the reason a
simple little piece of equipment like a PA can turn into a screeching
roaring monster worthy of any B flick movie. Before you go running
to your EQ though, try playing with their placement to try to deal
with your feedback issues.
Feedback
Feedback is a particular frequency that rings repeatedly causing
a loop and generally a big downward spiral of obnoxious noise. There
can be a number of different reasons for feedback. The three most
common I have encountered are having your reverb up too high, the
microphone to monitor equation and microphone, and monitor with
just about anything else on the stage equation. Having the reverb
up too high can easily be fixed by drying up your tone a bit and
turning it down. The microphone to monitor thing needs to be fixed
by Moving the monitor, getting rid of it, or doing whatever it takes
to get rid of the problem. Acoustic electric guitars are notorious
for creating loops with both monitors and mics and if you don't
have a feedback buster, detector or built in EQ; you'll have to
EQ the noise out through the mixing board. Another common example
of this type of feedback is a low-end loop created by monitor/ mic/
kick drum or monitor/ mic/ bass amp. Try facing bass amp into another
direction to see if that helps and if not, pull the monitors away
from the kick drum. That usually cures 'most' of the low end feedback
problems.
Luckily, you can also use an EQ to pull the sound out of the mix
so no one hears it anymore. One of the fancy Gizmos I was mentioning
earlier that can come with mixers is a built in equalizer with a
feedback locator. A little red light will appear above whichever
EQ slider is feeding back and all you have to do is pull that one
all the way to the bottom and Hooray, job well done, problem solved,
no more feedback! Otherwise you have to pull all of the faders down
to the bottom and bring each of them back up slowly one at a time
in order to find whichever frequency is feeding back and eliminate
it that way… a very slow process.
EQ
Other than eliminating feedback, an EQ is something that usually
gets abused and overused. People generally think that because they
can mess with their sound, they should. This is not so. Equalizers
are meant to reduce the possibilities for abnormal volumes in frequencies,
not to boost anything. If you have too much treble, don't aggravate
it by just adding more bass, pull the high end down a bit, particularly
just the one frequency that is either feeding back or ringing out
inappropriately. A flat line EQ doesn't mean that you don't know
how to do sound, it just means that you have perfect sound that
doesn't need doctoring for that particular room. So feel free to
slap anyone who comes along to pull the faders into a little happy
face to "make it sound better" for you. [Please note: Gear Snob
and/or WOMANROCK.com does not encourage permanent damage to any
persons who dare touch
the gear of people who have read this article and is/are in no
way responsible for the hospitalization of anyone who would
dare do so. ; ) ]
Volume
The last thing I'm going to address is Volume. The challenge with
volume is trying to keep the room at a reasonable level while maintaining
clarity of sound. We already know to keep the speakers up off the
floor to get a more pure sound to the patrons, therefore reducing
the need for higher output. But how loud should you go? The first
step is to keep the wattage to patron ratio in mind. (One watt per
person) The second is to keep your patrons in mind. Dancers or people
standing and milling about absorb more sound than people just sitting
there. You third option is to get a decibel level monitor. It's
a good thing and can help avoid fines or volume related lawsuits.
You should have the volume at 95 decibels or less in the middle
of the room for an animated or loud dancing crowd, and of course
much less for anything else. Anything louder and you will guarantee
ear damage or tonitis not to mention people with sore voices from
trying desperately to talk over you. 95 decibels is very similar
to a human shouting in your face. 125 decibels is the same volume
as a jet plane's engine in your face. Sounds impossible to achieve
that, but your average drummer alone can pull it off easily without
even being mic'd. So there you go, try to keep it down for everyone's
safety.
Public Address systems are not as difficult as they first appear
to be, they are what you make them. A little knowledge goes a long
way. Don't be afraid to pick the brains of other sound people or
your local merchant during the purchasing process especially regarding
warranty, upkeep, price, and quality for the different brand names.
Remember to keep it simple, and don't get more than you can handle
or even want. Although a 5000 Watt amp with 100 effects and 12 lines
is complete overkill for an acoustic duo, it may be the minimum
required for a full on five member rock band. So cheers to you and
your sound and good luck!
More from Corralee Booth...
How To Be A Gear Snob: Groovy
Tones.
How To Be A Gear Snob: The Bottom
Line on Bottom End.
How To Be A Gear Snob: Simon
and Patrick.
How To Be A Gear Snob: Speakers.
How To Be A Gear Snob: The Gibson
Guitar.
How To Be A Gear Snob: Pickups.
How To Be A Gear Snob: Gifts
for Rock Stars.
How To Be A Gear Snob: Fender
Stratocaster. |
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_________________________________
Want more Music Resources? Amanda Garrigues is a singer and
songwriter based in Gainesville, Florida. She runs her own label,
Average Sinner Records. She has contributed many great columns to
WOMANROCK.com including:
From the Couch to Carnegie Hall
Opening the Heart and Soul
How to Care for Your Voice
Being Sick on the Road
The Tour
Safety on the Road
The Art of the Music Conference
Distribution for Indies: How
to sell CD's without a Major Label
Mastering: What Is It Good For?
The Path of the Song: Deconstructing
the Songwriting Process
EQ That Guitar!
Choose Your Acoustic Wisely
In the Booth: Getting a Good
Vocal
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_________________________________
Corralee
Booth is a writer, musician and self proclaimed gear Goddess. She
sells and reviews gear at Guitarworks and plays bass for the Alberta
based, all girl band, Dragonfly. |
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