Chapter 9

Equalization (EQ)

When Eddie Van Halen’s amp tech was asked what an essential pedal is, they answered an EQ pedal. That gets a resounding yes from the entire guitar and sound engineering community. There is no more magnificent tool for surgical audio processing than the equalizer. It is essential to any amplifier, even if it is just a tone dial. With more than one frequency band to slide, you can greatly alter the tone.

You can assemble scores of EQ-altered moments into a complete track, and the difference between their raw recorded sound and the EQ-edited mix is a world apart. EQ is a lot of what sound engineers do. Remastering also uses these techniques. Mixing desk channels are bursting with EQ controls. DAWs have them as a standard despite an EQ meeting the criteria for being a plugin. Amps have EQs. Lots of pedals have tone dials. That is how vital EQ is. EQing can separate the wheat from the chaff of sounding good or bad, and it can ruin all the work gone on before if done wrong.

EQ is all about fine-tuning when it comes to guitar. However, EQ is also more than capable of frequency manipulation, notably subtraction and increases of frequencies present. There is additive EQ, which adds volume to frequencies there. There is subtractive EQ, which reduces the volume of selected frequencies.

Electric guitar EQing is quite technical and specific. It is worth spending time on learning this section. Guitar amps by design, especially high-gain amps that compress (think: evens out the sound) as they distort, remove the very low and very high frequencies. We will talk about those frequencies later, but this is a concept to consider for now. In addition, get a feel of the electric guitar EQing soundscape as a mid-range instrument. Guitar tube amps and guitar speakers, also meaning cabs, aren’t designed with very low or very high frequencies in mind (except for bright amps like some Marshalls, for example). So again, we have that mid-range concept appearing once more. A bass guitar is very different.

We should ask why amp makers allow for higher frequencies or lower frequencies than guitar mid-range in the first place. Amps at high volumes allow for certain guitar after-effects, such as harmonics, especially from the bridge pickup. Harmonics involves ringing guitar sounds that can be controlled rather than sounding like mistakes. Techniques such as pinch harmonics, hammer-ons, and pull-offs can produce a particular dramatic snapping that gives out a note that goes into these higher frequencies than even soloing on the higher frets does.

Soloing on the higher frets is still mid-range, but the upper mid-range. The electric guitar rarely stays in the higher range of vocals, drum high-hats, or the lower bass guitar frequencies. However, pinch harmonics or effects that achieve higher frequencies are part of the electric guitar tonal experience. Pinch harmonics often accompany metal guitar playing in some songs to significant effect. So, high-gain amps tend to be aware of a need to factor them into the amp design considerations. That explains why guitar amplifiers also cover higher ranges than seems necessary. Also, there are very bright amps, as we mentioned.

Mid-range tone sculpting

Guitar speaker frequency range (Hz). Notice the mid-region is divided into three areas? The mids are the three lighter regions in the middle. Most electric guitar speakers will vary in this area, so they sound different. Your amp has a tone in this region and speakers, also.

A typical electric guitar frequency chart will divide audio regions into frequencies running 0 to around 20,000. The unit of measurement is Hz. At 20 000 Hz, this will sometimes be written as 20Khz. The other axis of the chart is often 0 to 100 for decibels units as a volume level. We don’t need anything else as we want to see the regions to know where they are.

A big difference between a live performance sound and a mixed recording is that DAW EQing will carve off frequencies that come from the speaker and are undesirable. These correspond closely to the extreme darker areas in the chart.

• You will want to remove the bass muddiness around the 100 Hz region (say -40, +20, but it can vary).
• Somewhere between 8kHz to 10 kHz, you will want to cut off the higher frequencies to kill off the piercing high end. It can also go up to somewhere around 12 kHz.

If you want to remove them from a live performance without a mixing desk, then an EQ pedal at the end of the pedal chain is how to shape that off before it hits the amp. However, they are different methods and don’t sound precisely the same.

There could be an icepick sound, possibly somewhere in the upper mid-range, which you may want to remove. You discover it by increasing frequencies (level up and down and onto the next slider) until you find the one creating that harsh icepick sound, and that’s the frequency you want to subtract. With a DAW the EQ software lets you graphically move a point around the top of the graph to find sounds you want to subtract.

That is a crucial skill of chasing a frequency around by going from one band to the next slider on the EQ pedal to find that sound you don’t want to hear by detecting through loudness and then, after isolating it, subtraction.

Aside from the big chopoffs at each end and this ice-pick sound removal, which may or may not be there, you only need minor adjustments to add or subtract the frequencies you are interested in. It’s a notch on the slider here, but not to 10 max—just small increments if you must do anything. If you need to make massive changes to the mid-range, you should go back to the rig, fine-tune there, and record again. EQ is always used for fine-tuning but can also line-level boost a signal and whatever frequencies you want in additive EQing. Being a fine-tuning system means barely nudging a level or scarcely turning a dial to sweeten frequencies. Minor adjustments are all you should need to do once you have homed in on your tone with your amp. Let me put this another way. There comes a time when you maybe should consider how much EQing your amp needs to get you there. Your amp isn’t broken or something. This indicates you should consider another amp for the job.

Nudge EQ slightly to hear changes, not big jumps and shifts. You are far more likely to find an excellent tone by successfully dialing in anything in your rig once you have a fundamental tone. We are EQ sculpting, not just throwing around dials to see what happens randomly.

At this junction, it is worth discussing that this mid-range shaped frequency range is also what speakers do. Moving large volumes of air through a gradient and voicing it together acts as an EQ, highlighting some frequencies and rolling off on others.

Guitar speakers don’t alter extreme high and low end but, more specifically, the low and high mids that form the mid-range. Thus, low-mid and high-mid regions are of extra consideration. Both are in the mid-region divided up.