EQ essentials
What’s The Frequency Kenneth? Tips on EQ for your flat-top
How to enhance your acoustic tone with pre-amps and more
I’ve been playing guitar for a good few years now, but have recently started playing out at jam sessions and open-mic nights (and afternoons!). I’m also hoping to start some acoustic duo/trio gigs with a couple of friends, which also means we’ll need a demo recording. Here is the problem: on the gigs I’ve done so far the sound has been greatly variable. At one, my Taylor 314ce (plugged in) sounded raspy and thin; at another it sounded glorious and another still the sound guy was asking me what I wanted/how it sounded, and I didn’t really have the words to answer! Can you help me (us) understand a bit more about EQ for live and recording please? Patrick Kelly, via email We’ll give it a go, Patrick. It’s a massive subject and of course each guitar will require slightly different treatment. However, there are some generalities that are worth knowing that will help you solve problems relatively quickly. And that’s the point, really: in a live situation you’re usually correcting ‘problems’ created by plugging an under-saddle/ contact/soundhole pickup directly into an amp/PA. You’re aiming for what works there in that moment, in that room, for that performance.
When recording you have vastly more control over the situation, not least that you’re probably using microphones instead of the on-board pickup Let’s dive in…
Equalisation Basics
We’ll start right at the beginning, with apologies for over-simplification if you already know this stuff. EQ refers to frequency equalisation when it comes to audio signals. We should all be familiar with the ‘standard’ graphic equaliser layout; a series of sliders that adjust a range of frequency bands. You’ll usually find low frequencies on the left, progressing through midrange, to high frequencies on the right as you look at it. In this kind of equaliser each slider is basically a volume knob for that specific band of frequencies.
Where you don’t have a graphic EQ (for example on a mixing desk channel or acoustic amplifier) you’ll usually have a series of rotary pots, each of which deals with a wider band of frequencies than you’d find in a single graphic EQ slider: bass, middle and treble.The mid may also have a parametric element that enables you to choose the range of mid frequencies you want to adjust, more of which in the next section.
So far, so simple, but if you’re not familiar with how a graphic equaliser works, you can open up pretty much any simple DAW or other recording software (GarageBand or what have you – even iTunes or some other music player), find the ‘EQ’ or‘ equaliser’ section/ plug-in and mess around with pushing sliders up and down to see what does what.
Parametric EQ?
When you’re dealing with a ‘normal’ graphic EQ, each slider is at 0dB (no level change for those frequencies) in its centre position. Pushing the slider up increases – boosts – the level of the audio at those frequencies, and pulling slider down reduces – cuts – the level of those frequencies, giving you very targeted adjustment ability right across the range. Contrast that with the bass, middle and treble controls on a normal electric guitar amp, for example. They’re still EQ controls (and they often work in a different way, but we’re not getting into that!) but each one has a much wider focus in terms of its frequency range.
The halfway house between a full on graphic EQ and a simple bass/mid/treble approach is to incorporate a parametric EQ section. These are normally found in the midrange frequencies. Many mixing desks often have at least one, some have two or more. There are also plenty of pedals with parametric midrange EQ sections, and of course a number of on-board guitar preamps have one, too.
A parametric EQ control is usually two separate rotary pots/sliders, or one dualconcentric pot. You choose the frequencies you want to boost or cut with one knob, and adjust the amount of boost or cut with the other. The effect is the same as using a graphic EQ slider or two, except you get to choose which ‘sliders’ the parametric EQ controls with the rotary pot. They are immensely useful for making acoustic guitar pickups sound more ‘natural’, getting vocals to cut through and also for feedback busting.
Acoustic Guitar EQ
We’re always using terms such as ‘low end’, ‘bass’,‘midrange’,‘highs’ and so on, but what do they actually mean? The basic graph at the bottom of the page will give you a very rough guide where to start tweaking if you have a graphic EQ or a parametric handy. Obviously it’s guitar dependant to some degree but it’s useful nonetheless.You’ll get very similar frequency steps if you pull up a channel EQ plug-in inApple Logic and other common DAWs.
How Much & How Wide?
You have an idea of what frequencies do what, but when you cut or boost them there are a couple of other factors that come into play. First is the amount of cut or boost. It’s a common saying with EQ but a little goes a long way. For example if you’re giving a presence boost between 2 and 5kHz, 2dB of boost over that whole range can be significant, depending on your guitar, mic and all the rest of it. However when attenuating a problem frequency for feedback reduction, for example, a much deeper cut over a smaller range of frequencies is what you need, for example -15 or 20dB at 850Hz.
The range of frequencies that are being boosted or cut is called the ‘Q’. This is very easily adjustable in software EQ plug-ins, but it’s usually set in a hardware/pedal EQ. A high Q will enable you to boost or cut a very specific frequency, whereas a low Q will affect a wider band of frequencies.
Putting It Into Practice
You can read every magazine article in existence, every forum post and every online guide (and we suggest you do at least some of that), but at the end of the day, the most important thing is that you understand your own guitar. We’d highly recommend spending some time listening to it plugged into a PA, and/or through studio monitors when recorded, playing material that you know well. With a helping hand from a friend, you can come up with your own terms for the various parts of the EQ spectrum. If the open G string at its most disgusting sounds like a duck to you, identify the frequency band and call it the duck sound! It’ll make way more sense than something arbitrary that we’ve suggested.
Keep in mind that your ears quickly get tired, so if you find yourself becoming confused, take a break and come back to it; maybe listen to some classic recordings to help you reset.
Finally, and back to the original question: what to say to the sound engineer? How about a question? What does he or she think – how would they describe it? You never know, you might both learn something from the ensuing conversation!