EFFECTS
A basic understanding of guitar effects is essential whether you use a multi effects processor or individual floor boxes.
Effects generally occur in a chain. In other words, the signal goes through one effect, out of that and into the next. The order that the individual effects occur in this chain, is very important to how they'll function and effect the sound.
Below is a list of all the basic effects in the order in which they should normally occur in the chain. If you wish to jump straight to the section for a particular effect, just click on one of them below, otherwise read on. (use anchors for each effect)
[Compression]--[Distortion]--[Noise gate]--[EQ]--[Chorus/flange]--[Echo]--[Reverb]
Although in theory, you can put effects an any order, there is one definite order, that will give you the set of commonly heard professional sounds.
There are also certain categories of effect which most effects boxes will fall into. Up until recently, all multi effects boxes contain effects which fall into exactly the same categories. Now Boss (Roland), and no doubt soon others, are bringing out some new devices which seem to be significantly changing the age old set of effects, with some amazing results.
However, here we will be covering the widely available set of effects that most guitarists either already have, or are likely to get in the near future.
So lets look at them one at a time to get the basic principle of how they work. This is strictly from a musician's point of view here, I won't be using any recourse to electronic terminology or jargon. Also the order in which I go through these effects is the same order in which most guitarists will want to have them for almost all purposes. The reasons for this will also be explained.
Most of these effects are also the mainstay of the effects used in recording studios. So if you have a good understanding of how the guitar versions work, you'll also understand at least basically, how the studio versions work too.
Compression:
Also called sustain (because that's part of what it does). This effect is really a sound activated volume control. Think of it as a volume knob that is electronically turned up and down, depending on how loud the guitar signal going into it is.
It works like this: If the signal of the guitar is loud (for example you pick hard), the compressor will instantly turn down the volume. If the guitar signal is quiet (for example if its a sustained note that is fading away), the compressor will turn the volume up.
One important result of this is that as your sustained notes fade away, the compressor will be turning up the volume. So it will sound as if the notes are not fading away, but staying at the same volume - hence in effect, it sustains the notes. Eventually, when there's nothing left to sustain, the compressor will have turned up the volume so much, that you'll hear the background noise and hiss being amplified. This can be stopped by the use of another effect called a noise gate, which we'll look at later in the article.
Because a compressor effects loud sounds by turning the volume down, the attack of guitar notes tends to be softened. Since the actual picking or strumming of a note tends to be the loudest part, this is the part that is reduced in volume. The result of this is that the sound of strumming and picking is smoothed out. The down side of this is that, a hard pick or strum will be much the same volume as a soft one. This, if over used, tends to reduce both the impact and the subtly of music. However, used in moderation as a sustaining device, compression is very useful.
The controls most guitar compressors tend to have are: "amount" and "attack". "Amount" is self explanatory. "Attack" refers to how quickly the effect will turn down the volume on loud notes, hence how much it will quiet down picking etc...
Studio compressors have much more detailed controls, but are basically the same devices.
The diagram below gives you an idea visually, how compression effects a note.
Distortion:
Also known as fuzz and overdrive. This effect gives the electric guitar the familiar full blown lead sound, but can also be used for rhythm playing in certain circumstances.
Getting Distortion in perspective:
Distortion is sometimes compared with the sound a tube (valve) amplifier gives the guitar when turned up very loud. Many people have the impression that its the tubes that create this full, "warm" distorted sound on their own. However, the speakers and the speaker cabinet also have a lot to do with the sound. This can be proved by connecting any good tube amp (set to sound clean), to a traditional Marshal Stack (cabinet and speakers). You'll be amazed at how much of the "Marshal" overdrive sound is actually in the speakers and cabinet. I'm not suggesting it will sound exactly the same as if you used a Marshal amplifier, but you can't help notice just how much of the "Marshal" sound comes from the cabinet and speakers.
You can't however, expect a distortion box to duplicate the sound of a tube amp and speakers. Distortion boxes and those found in multi effects units, produce their own sounds, which for many players surpass any imitative value. The fact is, that as far back as the mid 1960's distortion boxes were being used by great players, and are a part of many vintage recordings. The holy grail of the tube amplifier won't necessarily give you the sound vintage sound you hear on 60's recordings, if that's what you're after.
Many players dismiss distortion boxes as artificial, insisting that only a tube amplifier can give you an 'authentic' lead sound. Keep in mind that distorting your signal with a tube is just as artificial as using a distortion box.
If you've tried distortion boxes and been disappointed in the sound, it may simply be because you weren't preparing the signal correctly for them, they weren't matched to the guitar, or simply that they weren't the right type of distortion box for the sort of sound you're after. Also keep in mind that if you have the wrong sort of pickups, or the wrong sort of guitar for the sort of sound you are after, no distortion box will help you.
This as I mentioned earlier, is all about to change with the new technology already on the market in one or two multi effects units made by Boss (Roland). It is indeed possible to authentically produce pretty much any sound and any amplifier with this new technology, pretty much regardless of the type of guitar you have.
For most people now however, and I suspect for some time to come, the traditional method of effects is what you'll be working with.
Back to the chain:
As I mentioned a couple of paragraphs back, preparing the signal for a distortion box, be it within a multi effects unit or as part of a chain of separate boxes, can be very important.
In almost every case, it is essential to have compression before a distortion box in the chain. The reason for this, is that distortion boxes use the level or volume of the guitar signal to overdrive the distortion circuitry (clipping). Look at the diagram below, and you can see how an uncompressed signal is very loud when the note starts (when you pick the note), and quite soon afterwards, its relatively very quiet.
The result is, that the distortion box has a very uneven level to work with. If you set the distortion so that the main part of the note has a reasonable amount of distortion, the first part of the note which is louder (the attack), will be extremely distorted (too much). This results in a loose messy sound.
If on the other hand you adjust the distortion so that the first part of the note, the loudest part (the attack), has a reasonable amount of distortion, the main part of the note (which is much quieter) will have too little of the distorted effect and sound thin and weak.
If however, the signal is compressed before it reaches the distortion box, the unit will have a signal of a much more even volume to work with. The result is, that if you set up a reasonable amount of distortion, the whole note will receive that nice even amount, even on long sustained notes. See the diagram below.
There are one or two exceptions to this rule. Notably some of Rodger Mayer's (famed for making fuzz and octave and other boxes for Jimi Hendrix and many others) excellent fuzz boxes need to be connected directly to the guitar (with nothing in between) to work to their full advantage. However the vast majority of distortion boxes will work and sound much better with compression before them.
Noise Gate:
By the time you've compressed and distorted the signal, you'll find that this will have created a lot of hiss and noise in between notes. This is caused by the amplification of the natural background line noise in the guitar pickups and audio wires, when the signal is compressed and distorted. You won't hear this noise until you stop playing, or until a sustaining notes has died away, then you'll hear the noise emerge.
A noise gate solves this problem. Its bit like a compressor in reverse, in the sense that it is a type of electronic volume control. Only unlike a compressor, a noise gate turns the volume on when it senses a signal (a note) and then turns the volume off completely when it senses that the signal (note) has ended.
Its important that a noise gate be adjusted so that it turns off the volume just before the noise becomes apparent, but not before sustained notes have died away.
Like compressors, noise gates are an essential part of any recording studio. Also like the compressor, you'll find that the studio version of the noise gate has much more detailed controls than the guitar version, though its basically the same device.
EQ:
Also known as Equalisation. This effect is basically a fancy set of very powerful tone controls. A good EQ is one of the most powerful effects at the guitarists disposal. Used with skill, a quality EQ can make the difference between an "OK" guitar sound and a "Really great" guitar sound.
Be aware though, if you find yourself making anything more than subtle settings with an EQ, you are trying to change the essential sound of your particular guitar and pickups. This is rarely a good idea (unless you're trying to create some sort of "special effect"). If you're trying to get the sound of a Strat with single coil pickups by using EQs on a Les Paul with humbucking pickups, you'll never be able to do it, you'll just end up with an artificial sounding poor imitation.
However if you have a guitar that already sounds a bit like a Strat, you can use EQ to make it sound even more like one. Or if you have a good lead sound, you can use EQ to make it sweet, warm, full, cutting, grungy, metallic, blusy, jazzy etc...
Keep in mind, EQ cannot turn a poor lead sound into a good one. However it can be an essential ingredient in a great lead or rhythm sound.
EQs come in two types: Parametric and Graphic.
Parametric allows you to select any frequency (often within a given range) and then boost or cut that frequency. The width of frequencies affected (called the Q) is sometimes also adjustable, but usually not on guitar effects).
Generally speaking you need at least three of parametric EQs to make useful alterations. One for the high frequencies, one for mid and one for low frequencies. Often they are already split into these three frequency areas, but within each specified range, you can select any specific frequency you like to boost or cut.
For example if the high frequency EQ's range is from 8KHz to 2KHz, you'll be able to sweep around to any frequency within this range. With parametric EQs for high, med, and low, you can generally shape the sound of your guitar effectively.
Graphic EQ. This type of EQ gives you lots of separate EQ's at set frequencies which you cannot change. You can however boost and cut them. The advantage of a graphic EQ is that you can effect many frequencies at the same time instead of just two or three as with the parametric. Also the name graphic refers to the fact that once you've made your settings, the positions of the sliders (used instead of knobs on graphic EQs) be they real or represented on a screen, let you see the shape of the frequency effect. This visual cue is in fact very useful for intuitive effect programming.
Also, as long as the frequencies in the graphic EQ have been chosen (by the manufacturer) appropriately (for guitar) you get far more control over the accurate shaping of the guitar sound. At present (to my knowledge) the only multi effects unit that contains a graphic EQ are the best of the Digitechs. If what you are looking for is quality and fine tune controllability of the shape of your sound, I recommend a graphic.
Chorus and flanging:
Also often called modulation. These two effects come from the same device. In fact all they both consist of is a very quick echo, where the speed of the echo is shifted up and down on a cycle (oscillated or modulated). The original sound is mixed with the delayed sound (the fast echo). However the delay is so short, that you can't actually hear it as a separate echo, it seems to sound at the same time as the original. When the delayed sound's delay time (the speed of the echo) is moved up and down(modulated), lots of different frequencies get cancelled and added as the delay time changes, creating the effect.
The difference between chorus and flanging is only a matter of exactly how short the basic delay time (echo) is. Flanging occurs at around an 8 millisecond delay (though this can vary both up and down quite a bit). Chorus occurs at around 18 milliseconds (this varies as well). The times vary to the point where, what one company calls flanging, another company may call chorusing.
One other difference common to flanging however, is the use of quite a bit of feedback. In this context, feedback refers to how many times the (very quick) echo repeats before it dies away. Flanging tends to have a lot of feedback as well as a shorter delay time. Chorusing tends to have little or no feedback as well as the longer delay time.
The depth control in both chorus and feedback controls how much the basic delay time is varied when it cycles up and down (also known as modulation, oscillation or LFO). So for example a flanging effect may have a basic delay time of 8ms, but it may cycle up from this to 12ms and then down to 4ms, 8ms just being the centre of the cycle. The greater the depth, the more extreme the effect will sound.
The rate control also in both flanging and chorusing, controls the speed at which the delay time is cycled up and down. This is just up to personal taste. However traditionally, flanging has a slow rate (sweep), where as chorus tends to be faster.
You'll find pretty much the same controls on the studio versions of these devices, though often you'll have one device that can be used to create either chorus or flanging, just depending on what delay time you set.
Echo:
Also known as delay, this is usually next in the chain of effects. Chorus and flanging are normally used as relatively subtle tone shaping effects that appear to be 'part of the guitar sound'. Echo tends to sound most effective near the end of the chain, echoing the total sound of the guitar including distortion, chorus etc... Putting echo earlier in the chain can add mess and clutter to the sound, as each echo is chorused or flanged, the result can cause mayhem. On the other hand, there are no absolute rules about this, and some players put echo earlier in the chain with interesting results. Unless you have reason not to, I suggest you put it at the end of the chain of effects just before reverb.
Echo is a simple enough device. You can vary the delay time, which is the length of the echo, and you can vary the feed back, which is how many times the echo repeats before it dies away.
The studio version of this may have significantly more controls. Since chorus, flange and echo are essentially the same device, you may find one piece of studio equipment (a delay line) used for all these effects.
Be aware that echo can easily cause clutter and messiness in your sound. Unless you are playing long sustained notes or want a special effect, echo is best kept fairly quiet with delay times at around 300 or 400ms.
Echo can create a big sound and a sense of space, often at the expense of clarity however, if you're not careful. Its also very useful for long, slow sustained notes especially if you fade the notes in with your volume knob or a volume pedal.
Reverb:
Reverb is different from echo in the fact that you can't hear any individual echoes. None the less, reverb is in fact in a basic sense, lots of echoes of different lengths happening at the same time. Although there is more to it than this as I'll explain.
Reverb simulates the sound of an environment ie: a room, a concert hall, a corridor etc... To do this, reverb simulates the various acoustic phenomena that occur as a sound bounces around and reflects off the insides of the room or hall.
There are various controls (parameters) that most reverbs have in common (excluding the spring reverb you get in a guitar amp). Unfortunately, companies have not standardised what they call these controls. The lack of standardisation is to such an extent, that I can not list all the permutations, of what various companies call various controls here. It will have to suffice to say, that what ever they're called, all reverbs have basically the same controls (though some have less than others). Thankfully, fiddling with the subtleties of all these controls is probably the least important thing to worry about for a guitar sound.
If you're recording in the studio however, I suggest that you turn your reverb off and let the studio use theirs. A high quality reverb in the hands of a skilled engineer or producer can do amazing things in a mix.
The main thing to remember is that, too much reverb will muddy and swamp your sound, too little will make your sound very dry and stark.
Its also worth pointing out, that although you are often supplied with a lot of subtle controls for reverb, once you have bass, drums, keyboards, vocals etc... all playing live with you on stage, a lot of these subtleties will be completely lost.
Here we go with a list of the parameters (controls). I've used Lexicon's names for the controls here.
Predelay: this the amount of time it takes for the main part of the reverb to sound once you've played a note. The longer this time is, the bigger the simulated room will sound.
Early reflection: this is the part of the reverb that simulates the sound that's reflected off surfaces near you, as opposed to the sounds that bounce off the back of the room or hall. So these sounds tend to be brighter, sharper and less dense than the rest of the reverb. Turning up the amount of early reflection, and even having only the early reflections, (turning off the rest of the reverb) can sound great on percussion. However on guitar, turning up the early reflections is generally only useful as a special effect. For normal reverb sounds, early reflections should be left at moderate settings.
Size: This term can vary from one company to another. However, it usually refers to the general density, of the many separate echoes that make up the reverb. ie: the greater the distance between them supposedly, the larger the room. In reality however, the predelay (see above) has a more realistic effect on the apparent size of the room. What some companies call size is in fact predelay.
If the size control does refer to the density of the echoes (as most seem to), the lower the value the smoother the reverb sound, too low though and it starts to sound metallic. Higher values can sound bigger (in a way), but also less smooth.
Time: This parameter (control) refers simply to how long the reverb continues on for after you've stopped playing. This is not to be confused with the size of the room. What the time control represents, is how reflective the room or hall is.
Diffusion: Normally only found in studio reverbs, this control is sometimes found in guitar effects reverbs. This controls the softness and smoothness of how higher frequency sounds are reflected in the reverb.
HPF and LPF: These are tone controls generally used by studio reverbs and the more expensive guitar processors.
HPF refers in effect, to which bass frequencies are to be cut and by how much. HPF stands for High Pass Filter, in other words it allows high frequencies to pass, but not low frequencies. You can of course vary at what point in the frequency spectrum the lows (bass) gets cut.
LPF refers to which high frequencies get cut and by how much. LPF stands for Low Pass Filter, in other words it allows low frequencies to pass, but not high frequencies. You can of course vary at what point in the frequency spectrum the highs (treble) get cut.
If all this is confusing, just remember: LPF = remove the highs and HPF = remove the lows.
Tone: very straight forwardly allows you to adjust the over all amount of highs and lows in the reverb. Terms like warm, dark, and bright are often used by manufacturers here.
Roll off: Always found in studio reverbs but also found in the some of the better guitar processors, this is the speed at which the high frequencies in the reverb decay. So if you wanted the reverb to start bright and end dark, this might be useful.
Gated: This effect makes the reverb sound come in suddenly and then just as suddenly its cut out. This is generally reserved for special effect purposes when used on guitar.
Preverb or reverse: This makes the reverb fade in and then stop suddenly, imitating the sound you get when you record reverb while running analogue tape backwards. This is a special effect sort of sound. Some computer based sound software like Sound Edit, actually allow you to have the reverb arrive before the sound that's being reverberated.
