Tuesday, November 13th, 2018

Columnist Paul Atkins : how to adjust a FOH EQ for a live performance

By Paul AtkinsJune 1, 2012

CREATIVE

Paul Atkins

Paul is an engineer, producer, composer and musician who these days spends a large portion of his working life mixing FOH sound either on tour or in-house at London venues – including the legendary 100 Club.

His studio credits include Lucky Soul, The Hope Rebellion and Nick Evans and he tours with Various Cruelties, Eli ‘Paperboy’ Reed & ZZ Ward mixing FOH. He’s also performed on stages around the world and on many recording sessions over the last 20 something years.

Unless your working on big budget tours where you get to carry your own desk with the show pre loaded and your pick of PA system expertly rigged for you every night chances are you’re going to be given some less than ideal rooms, mix positions and equipment on tour or working in-house at a venue.

EQ’ing a room is a mixture of skill, experience and alchemy and has a massive impact on pulling off a successful mix. This month I’ve put together a rough guide aimed at people starting out as an audio engineer or anyone eager to get a better sound out of their PA system using a 31 band graphic equaliser.

EQ’ing the room

Lets say you’ve just landed your first in-house job or even your first tour as a audio engineer.  You’ve mixed a few live shows for friends bands and know the difference between a Beta 52 and a B-52.  You’ve turned up early for your first show armed with all the bands tech specs either scribbled out, printed out or stored on your phone.  You’ve had the guided tour from the head engineer and heard all the story’s about great sounding gigs played there in days gone by and what frequencies to watch out for on the FOH graphic.  This won’t be a problem though as the equaliser settings are always left the same.  But, shock horror, the visiting engineer from the night before zeroed the graphic!  Now what?  How do you set the EQ so the PA sounds amazing when the band starts sound check…which is in 10 minutes ?!

You’ve got a few options but the two most popular ways are talking through a microphone and playing a familiar song or two from your mp3 player.

Klark Teknik DN360 Graphic EQ : A classic!

 

Your own voice through a microphone

Which ever sound source you choose for your reference point it needs to be something you’re familiar with.  Something you’re very familiar with is the sound of your own voice.  If you’re going to talk through the PA then you’ll need to plug the microphone directly into the mixing desk, preferably the one the lead singer is going to use, so you can tweak the EQ while you speak, searching for frequencies that either sound too prominent or want to feedback.  You can do this by quickly moving faders on the graphic up a few dB, 6 or 9 is usually enough, and when you find one that either leaps out (making your voice sound odd) or begins to squeal reduce it a few dB below the flat or ‘0’ position.  I’d suggest 3dB to start with, more if you think it’s necessary.  Be mindful that the faders on the graphic are volume controls, very specific volume controls, and if you cut a lot of frequencies by large amounts you may find the PA or parts of the PA aren’t loud enough when the band starts playing.

Once you’ve been through the spectrum and you’re happy with your setting it pays to walk the room while you talk through the microphone so you hear what the audience are going to hear.  Oddly, it’s not very often you’ll find a mixing desk in an optimum listening position in a room so familiarizing yourself with the audiences point-of-view is a good idea.  This also gives you a chance to hear the anomalies of the room and/or the PA system.

If you can stand in the middle of the room talking loudly through the microphone and your voice sounds full spectrum, balanced and with no feedback then you’ve probably done the best you can.

Familiar piece of music

This is my preferred method for setting the EQ and I’ve been using the same song for a few years now.  It’s a song called ‘Ain’t nothin’ like a shame’ by Lucky Soul and is a recording I know very well (I played drums on it).  It’s a full spectrum well balanced recording with tight low end, fairly soft midrange and plenty of hi end information the whole way through.  It’s particularly good at showing up systems that have harsh mid range and dull top end and because I know the characteristics of the recording I know where to head on the graphic whenever a PA doesn’t reproduce it in a familiar sounding way.  This saves time, leaving you more time for when the band arrive.

I prefer this method over talking through a microphone because a recording is going to consist of more frequencies more of the time than your voice ever will.  And while you can vocally imitate a bass drum or a hi-hat it’s not easy to do these simultaneously and consistently.

With ‘Ain’t nothin’ like a shame’, I know that if the vocals and guitars have too much bite, then I’ll start pulling down a little bit of 3.15kHz.  If the vocal sounds too woolly then some 250Hz might need to come out etc etc.  If these aren’t the culprit frequencies they they’re going to be pretty close.

https://www.audio-times.com/audio/Ain’t nothin’ like a shame.mp3

 

Things to be aware of

You can’t change the laws of physics but if you understand some basic principles you’ll be better equipped to deal with the acoustics of a room – and know when you’re on a hiding to nothing.

Standing waves (or room modes) are often a problem in live venues and will give you a false idea of what’s happening sonically in the room, particularly in the lower end of things.  What might also be working against you is the position of the mixing desk.  If it’s right up against a wall, or worse yet in a corner, you may cut too much bass or sub bass out of the PA.  If you have then you’ll probably struggle to get the bass drum and bass guitar sounding nice and full relative to the rest of the instruments.  The result will be a band that sounds bass lite.  Or, to put it another way, a band with no cojones.

Here’s a link if you’d like to find out more about standing waves

When the band starts playing

One venue I often work at has polished wooden floors and the walls are mixture of painted concrete and glass.  Does it sound bright and echoey when it’s empty?  You bet it does.  Bands have even asked me to turn the reverb down in the PA during sound check when I haven’t actually added any.  When I explain that the room is bright and lively because its basically an empty swimming pool with a concrete lid on it they’re concerns are usually put to rest and they feel reassured they’ll sound great when the crowd arrive.  Usually.

When the band starts sound checking the room is going to respond differently to when you EQ’d using your voice or reference track so further adjustments may be needed.  Also bare in mind that empty rooms are a lot more reflective which can mean over compensating on the graphic.  Typically the top end can be very ‘zingy’, the mid range ‘glarey’ and the bass loose or ‘woolly’ depending on the room, the PA and the band that’s playing.  Vocal mics may feed back in the FOH speakers so be weary and be prepared to pounce on culprit frequencies.

Gig time

All this can improve, sometimes radically, with the addition of some audience members.  So much so that you may feel the urge to reverse some of the adjustments you made during sound check.  It can feel like you’re doubting yourself or undoing your own hard work to put back in frequencies you have painstakingly dealt with but, and this may sound very odd, remember to listen with your ears and not your memory.  Meaning, trust your ears and respond to what you hear at the time and not what you remember it sounding like before.

I’ve focused mainly on reducing problem frequencies but it’s possible that a PA system may be lacking in some frequencies too.  Another small venue I work at sometimes needs a little bit of a boost around 10 & 12kHz to brighten the system up a bit.  Be careful boosting low end frequencies, though, as you may start to overload the cross over or amplifiers which can result in broken speakers.  As tempting as it may be to compensate for underpowered bottom end your band is going to sound better with not quite enough sub compared to no sub at all.

Practice makes perfect

When you have the chance spend some time getting familiar with the effect adjusting all the frequencies on the EQ has on a piece of music.  Figure out where each instrument lives on the spectrum, how much is too much, and how much is not enough.  Remember that even if you’re working in the same room night after night the EQ isn’t necessarily going to be the same as the night before, even if last nights gig sounded amazing.  No two bands sound exactly the same, so it stands to reason that the FOH EQ will vary from band to band.

Paul Atkins
June 2012

Share on FacebookShare on LinkedInTweet about this on TwitterShare on Google+Email this to someone share with your friends

Audio Industry Tweets

© audio times 2018. All rights reserved.

Website by Small Business Marketing