EQ English @ Vettaville.nl

EQUALIZATION

Introduction

Have you ever found yourself listening to a car or home stereo and didn't like what you were hearing and immediately reached for the Treble (high frequency) and Bass (low frequency) knobs to adjust the sound? If so...then you just stepped into the world of equalization.

Now it's not my intent to try and cover every aspect of equalization in this article, because there could never be enough written. I'm also not going to focus on too much technical theory, because we're guitarists right - just give us the basics. So I'm going to try and write this article to be as simple to understand as possible.

What Is Sound Anyway?

In order to better understand the principles of equalization for tone manipulation, one needs to first understand the underlying nature of the audio spectrum. To put this all simply, sounds are made up of different frequencies. Different instruments sound the way they do because of the complex manner in which the frequencies they produce all add up. There are frequencies we can hear and those which we cannot hear. Why? Because the human ear is designed to only hear sounds that occur within a given frequency range.

So what frequency range can the human ear hear? A good, young, healthy, and undamaged ear can hear frequencies in the range of approximately 20Hz - 20kHz. Frequencies are often expressed in Hz (hertz) or kHz (kilohertz). For those who need to understand the math, 5000Hz = 5kHz, or 1.2kHz = 1200Hz, etc.

Take Note:

Things start to get a little more interesting when we start to look at how frequencies play their part in the guitar world. It helps to know that the lowest E-string on a standard 6-string guitar is tuned to 82.41Hz. It also helps to know that guitar amp speakers are not capable of producing too many frequencies above 4kHz. Guitar speakers are designed with a limited frequency response and cannot playback a full-range of frequencies such as recording monitors or a P.A. system. I know this is over-simplifying things, but Vettanarians should initially start off concerning themselves with the frequency range between 80Hz - 4kHz (and perhaps a little further on either side of this range if needed), when equalizing patches on their Vetta.

Guitar String Frequencies

			E = 82.41 Hz A = 110.0 Hz D = 146.8 Hz G = 196.0 Hz B = 246.9 Hz E = 329.6 Hz		When you consider the fundamental pitches of each guitar string, you will notice that they are towards the lower-mid end of the frequency spectrum. However, it is the actual harmonic overtone content of each string which pushes its tone spectrum into the mid to high frequency ranges.



20Hz	40Hz	80Hz	160Hz	320Hz	640Hz	1.2kHz	2.5kHz	5kHz	10kHz	20kHz
Low					Mid				High

The Ten Octaves of the Audio Spectrum
The audio spectrum which in which we hear is often divided up into 10 octaves to help define the particular musical, acoustical, and psycho-acoustical qualities within.	16 kHz	20480 Hz	Octave 10: Extreme highs, hiss, very little musical content here.
	8 k	10240 Hz	Octave 9: Highs, treble, metallic brightness, brilliance, upper musical content of guitar strings.
	4 kHz	5120 Hz	Octave 8: Presence, upper end of tone spectrum for many instruments, brightness.
	2 kHz	2560 Hz	Octave 7: Upper Mid-Range. Hardness, bite, intensity, loudness, definition. Major range of harmonic content for most instruments.
	1 kHz	1280 Hz	Octave 6: Mid-Range. Highest fundamental pitches reside here. Beginning of upper harmonics. Major overtones for most instruments.
	500 Hz	640 Hz	Octave 5: Lower Mid-Range. Body and richness of sounds. Fullness. Warmth. The primary treble of musical pitches resides here.
	250 Hz	320 Hz	Octave 4: The "mud" range. Thickness and muddiness, thump.
	125 Hz	160 Hz	Octave 3: Upper Bass. Musical foundation for many instruments. All speakers play back this octave.
	62.5 Hz	80 Hz	Octave 2: Lower Bass. Bottom of musical pitches, primary bass energy. Sonic foundation. Most loudspeakers can play back this octave.
	31.25 Hz	40 Hz	Octave 1: Very Low Bottom End. Little musical content here, too low to be played back by most loudspeakers. Non-pitched bass sounds.
20 Hz

Cutting Instead of Boosting

One of the biggest patterns of EQ behavior that people often make is that they tend to approach it by boosting the gain of frequencies rather than lowering them. It's not that there's anything actually wrong with boosting, but you can often achieve your tonal goal by negative equalization - by rolling off or reducing an area of frequencies rather than by boosting them.

Sometimes the tone (timbre) you are wanting to hear already exists within what you are hearing. The best analogy for this is to consider a stone sculpture. Think about how an artist can take a large piece of stone and then begin carving away the areas of the rock that are not needed to create the image they desire from within. This same approach can apply to creating guitar tones as well.

For example, if you find yourself boosting both the highs and lows, you can sometimes achieve the same (or better) results by scooping out the mids instead. Keep in mind that any time you can reduce, rather than boost frequencies, you are automatically helping to reduce noise as a beneficial side-effect. Second, if you can achieve the same results with one band of cut than two bands of boost, you have saved yourself an extra band for later use, and you are helping the original signal to sound more clear and clean.

Take Note:

When adjusting an EQ's gain up/down, reductions will generally be larger than boosts. Why? Because of the way in which our ears hear a change in sound. Please keep in mind that boosting a band of frequencies will tend to increase the overall signal level significantly, and if overdone, this can result in unfavorable effects upon your tone. On the opposite side of this, cutting a band of frequencies doesn't change the overall signal level much at all.

Graphic Equalizers

Graphic equalizers are certainly a great tonal tool for shaping sound spectrum, but they are not necessarily the best tool that could be used. As you can see from the image below, the center frequencies are set: 100Hz, 200Hz, 400Hz, 800Hz, 1.6kHz, 3.2kHz, and 6.4kHz. Please realize that with a graphic equalizer, you are not boosting/cutting just these specific frequencies alone, there are other frequencies on either side of these set frequencies which will be affected as well when you move the slider. In other words, these sliders have a fixed center frequency (which you see) and a fixed bandwidth (of which you don't really know - unless the manual tells you).

Anyone who has spent time working with an EQ stomp box has probably experienced at least one frustrating moment when you thought, I can get real close to the sound I'm looking for, but it seems the frequency I'm needing is in between two of these sliders - such as 300Hz, or 650Hz, or 2.4kHz, etc. You get the idea...

Even the Vetta's Graphic EQ center frequencies are set:

LOW = 80Hz

LOW MID = 200HZ

HIGH MID = 800HZ

HIGH = 3kHz

Take Note:

Graphic EQs limit your choices to specific center frequencies and pre-determined bandwidths to boost or cut. But because of the fixed nature of these guitar graphic-eq stomp boxes, they can teach you a thing or two about which frequency areas you should be paying attention to. When you look at most every eq stomp box like this, the frequencies are typically the exact same (or very close) for a specific reason. Why? Because many years of experience has taught design engineers that these are the frequency areas that are most often needing to be adjusted by guitarists.

Parametric Equalizers

When you want to get down to some serious frequency tweaking, the Vetta's 4 Band EQ is the tone tool of choice. Why? Because in addition to the Low & High Shelving EQs, there are two bands of fully parametric EQ. A parametric EQ is very powerful because it gives you complete control over the center frequency, the width = Q, and the amount of cut/boost. With a parametric EQ there are no longer limitations. You are no longer limited to the pre-determined center frequencies used in a Graphic EQ. So you can move them up and down the frequency range to dial into the specific frequencies (or area) that you want to.

Still confused - don't worry, parametric equalizers always seem to confuse and intimidate users, but they're really not that difficult to use or understand. Probably the most confusing aspect of a parametric EQ is the "Q" parameter, which just happens to be the real power parameter behind this type of EQ.

What is "Q"

The "Q" parameter is what sets the width of the band of frequencies that will be boosted or reduced. In other words, it determines the amount of frequencies on either side of the center frequency. The basic idea behind the "Q" parameter is this: why boost/cut frequencies that don't need to be. By being able to control the actual width of the band being boosted or cut, you have more flexibility to shape the EQ to fit your needs.

Understanding Q Bandwidth

The "Q" parameter is what sets the actual width of the band of frequencies you can work upon, anywhere from a very broad bandwidth, to a very narrow bandwidth. You can see this for yourself from the images below.

Take Note:

The images below are simply meant to provide you with a visual representation how the Q control of a parametric EQ allows you to widen or narrow the bandwidth of frequencies you boost or cut. So don't get hung up on looking at the Q numbers and bandwidths since the Vetta only allows for Q settings from 0.1 - 2.0, because these are more than enough to alter the audio spectrum of your guitar tone.

Looking at the Vetta Owner's Manual, many of you tech-heads may have noticed what appears to be a typographical error regarding the description of how the Q parameter works in the 4 Band EQ. I've checked with Line 6 about this, and the original manual described it wrong.

To set the record straight:

The implementation of Q in Vetta (and Vetta II) follows the normal definition of Q, where the higher the number, the more narrow the bandwidth, and the lower the number, the more wider the bandwidth.

Finding The Sweet/Sour Spots

One of the biggest frustrations with applying EQ is that we don't often know where to begin. Where exactly are the sweet spots that bring out the life in the tone? Where are those annoying sour spots that make us cringe? Should I boost or should I cut? Good questions - but very difficult to answer. Learning to use EQ can be an art all unto itself, and a very subjective one at that. But there is a fundamental method to help you get into the ballpark.

Effective EQ involves finding those areas of the tone that may need to be increased or decreased in strength. When you think a tone sounds too muddy or too bright, those are typically areas of the tone which contain more energy than surrounding areas.

Suggested Q Setting

In general, start with a "Q" setting of 0.7 - 1.0

The simplest method to find sweet/sour spots is to turn up the gain (about +10dB on the section of the equalizer you are using) then slowly sweep the frequency control up and down. Try not to focus on the overall sound itself, learn to listen for how the equalizer is affecting just the frequency area you are sweeping across. Remember, you are trying to dial into an area of frequencies (similar to a radio station). When you hit that area of resonance - which is that naturally occurring peak in the sound that already stands out as good or bad to your ears, this area might benefit from being boosted or cut. After you think you've got the right tonal color, then re-adjust the Q parameter to try and trim the bandwidth to just the right width that you need.

Less is more.

The minimal amount of EQ is usually best.

For instance, if your looking for the area that sounds "boxy" the boxiness will really jump out at you when you sweep across it. Once you've found the area you are looking for, then it's just a matter of deciding how much you want to get rid of. Return the gain to zero, then start adjusting the gain up/down until things sound like you want.

Take Note:

If you use the Vetta's 4 Band EQ, you can increase your accuracy in pinpointing the area of frequencies to be controlled by adjusting the "Q" control for a very narrow bandwidth.

Vetta Cab Models As EQ

Patch programming habits may be hard to break. Many of us are probably guilty of taking the easy (lazy) way out by just using the default amp/cab settings which come up every time, but that doesn't necessarily mean they're the best combination of amp, cab, and parameter settings. With all the tonal versatility that exists within the Vetta, experimentation will be the key to tonal success. And possibly one of the most overlooked applications of EQ are the cab models themselves.

Experiment with different cab models before reaching for the EQ

How many of the Vetta's cab models do we scroll right past and overlook because our narrow thinking has pre-conditioned us to NOT even consider using them? Don't think of the Vetta's cab models in terms of their speaker size and configuration, instead, think of them as 28 (different) preset EQ templates which must be tried out with whichever amp model you are working with. You may come to find out that the "magical" tone you're striving for suddenly appears from using a particular cab model you would have never considered using previously.

General Guitar Equalization Tips

While it is impossible to give EQ settings that would be guaranteed to give you the "specific" results you might desire, I've included the following "generalized" eq tips for guitar. There are no rules when trying to get the guitar sound you want.

Boosting somewhere between 75 - 90Hz can help to bring out cabinet clunk. Keep in mind that since the low E-string of the guitar is around 82Hz, it's not necessarily a good idea to boost the low frequencies below this note unless it helps you get your sound.

Cutting somewhere between 100 - 250Hz can help to resolve a boomy or boxy sound. Try a "Q" setting of 1.0 - 1.4

Cutting somewhere between 160 - 320Hz can help reduce a muddy tone. Try a "Q" setting of 0.7 - 1.0

Bite can be added somewhere between 2 - 6kHz.

EQ Food for Thought

I've noticed that quite a few Vetta patches seem to use the exact same amp model, cab, and parameter settings for both AMP1/2. And while this obviously will sound louder and more full to most, I've often noticed it can lean towards sounding less distinct and less clear when compared to using just one amp model with it's volume cranked via the Post Compressor.

Two absolutely "identical" amps are simply adding their frequency responses together, which can can lead to an over-abundance of frequencies in more than one area...and these areas can in turn start to push the speakers enough to where the tone starts to sound worse, not better.

Therefore, it might be a good idea to experiment with subtle equalization "cuts" in some frequency areas of one amp model so that it will still sound almost the same, but that it will compliment the final sound when combined with the second amp model.

Take Note:

It doesn't do too much good to add any really high-end boost, because a guitar speaker cannot produce frequencies much over 4kHz. But remember, rules were made to be broken, and if it works for you, then go for it.

Frequency Areas

The following EQ lexicon in by no means comprehensive and authoritative. Equalization can be defined with a variety of frequency vocabulary. However, many of these terms are fairly universal in the way in which they help our minds to grasp the realm of frequencies. Remember, many of these regions can overlap and often do.
Boomy - low lows, typically in the region of 40-60 Hz.	Telephony - a concentration of frequencies around 1.5-2.5 kHz.	Sparkle - extremely high brilliance almost beyond hearing, around 15-20 kHz.
Fat - region just above boomy, about 60-150 Hz.	Cutting/Biting - frequencies which cut through, about 2.5-4 kHz.	Brightness - can be achieved by a global shelving boost of everything above 10 kHz.
Woofy - in the region of 125-250 Hz.	Presence - anywhere from 3-6 kHz can make a sound more present.	Darkness - the opposite of brightness, a general lack of highs at 10 kHz and above.
Puffy - about 250-500 Hz.	Sibilance - the "s" sounds of vocals often found at 7-10 kHz.	Muddiness - excessive low end and also low mids, woofy and puffy combined.
Warm - often found between 200-400 Hz.	Zizz - a pleasantly biting high-end or brightness, around 10-12 kHz.	Thinness - the opposite of muddiness, a general lack of lows and low mid frequencies.
Boxy - usually found between 500 hz and 1 kHz.	Glass - very translucent but noticable brilliance around 12-15 kHz.	Openness - a quality of having sufficient highs and lows.
Remember that equalization is extremely subjective and totally dependent upon each and every guitar tone being worked on. Therefore, one rarely can say boost or cut "x" frequency by "x" number of dB and have it apply to every patch in a generalized (or specific) way.

Equalization Is A Fundamental Practice That Must Be Mastered