Everybody loves distortion. But not everybody knows how it is created. In fact most guitarists don’t have a clue. And their sound is usually evidence that they like distortion, but are not sure how to create the right kind. As a result, a lot of distorted guitars tend to sound fizzy and thin.
DISTORTION
Before I get into what a bad guitar tone sounds like, I need to address what distortion actually is and why it is so critical.
If you look at a normal waveform, there is usually a nice round curve at the lowest and highest extremities. This is a natural curve. But when we add distortion, we essentially clip the peak of the waveform. The sharper the clip, the more crisp the distortion.
In the picture above, one would hear a clean channel from the non-clipped curve, overdrive from the blue line, crunch from the orange line, and fuzz from the bright red line.
Each of these levels of distortion are called a lot of things but essentially the result is the same effect. The more you clip a waveform, the more distortion you introduce into the tone of a guitar.
We all know some distortion is good. And too much can be really bad. Too much distortion can sound cheap, unrefined, and just down-right amateur. Especially when the amp is also producing overtones and saturation that are not helping with the tone.
So how do we get clipping? Well in its simplest form, just about every guitar amp is built with intentional limits. When you push pre-amp gain or drive beyond these limits, your signal gets clipped, which produces distortion.
But there is a delicate balance between tone and distortion. If you go balls-out on a fuzz pedal, you may notice you lose a lot of tone. Your chord changes may be hardly noticeable. Fuzz is great for leads but can be a real tone killer for rhythm guitar.
This is because you are clipping so much of the sound wave, it loses its natural vibration. Like turning round tires into square blocks, the clipping overtakes the smooth rise and fall of the waveform, leaving little room for the actual note.
So if you maintain a proper balance between the type of distortion you desire and your tone, you should be able to dirty-up your amp and not sacrifice anything.
SOLID STATE V. TUBES
Tube amps are known for warmth and roundness. This is because tubes mostly generate even harmonics. If you are a guitarist who has played through multiple amps, you know exactly what a good tube amp can deliver. Without tube circuitry, and some power section magic, the lack of harmonics can be an unbearable sound. Thin and lifeless.
Harmonics are a huge part of a guitar tone because they add to the natural tone of the strings, especially when driven hard. Nothing beats the tone of a good tube amp. Nothing. Not amp sims, and certainly not Solid State.
As a mixer, my number one tool for taking an OK mix to awesome is harmonic saturation. without it, much of the music we have listened to for the last 100 years would be lifeless.
But then you have so many amps out there that don’t have a single tube. These Solid State amps depend on transformers and electronic wizardry to generate harmonics and clipping. And they do an OK job for the most part, if you spend enough. But frankly, most solid state amps are relegated to practice amps in my opinion.
Solid State does not generally produce even harmonics. They primary produce odd harmonics. And if you think of a cotton swab as an even harmonic, odd harmonics would be akin to a toothpick.
Take an A4 note vibrating at 440hz. The even harmonic series of any note is 2x, 4x, 6x, and so on. So A4 would be complimented by harmonics at 880hz (A5), 1760hz (A6), 2640hz (E7), etc. and tube amps deliver even harmonics in spades! An odd harmonic series of A4 would follow 3x (E6), 5x (Db7), 7x (G7), and so on. Solid State, without emulation, just can’t compete.
HARMONIC SERIES
What do harmonics sound like? Well, on a piano, hit an A4, E4, and A2 simultaneously. That’s basically an even series of harmonics, a chord. Now hit an A4, G4, and A5 simultaneously. This is an odd series.
When played through a tube guitar amp, a single note could have a mixture of even and odd harmonics added to it, mostly even. Conversely, the solid state amp will dominate the odd harmonic series.
It should also be stated that nearly every instrument generates harmonic series. Take for instance a drum. Depending on the head, the shell, the tension on the head, etc., a single hit will generate a fundamental note - usually the lowest frequency on a spectrum analyzer - and then a series of harmonics above it.
Look at a kick drum on a spectral analyzer, you will see way more than 150hz. This is because the kick drum is naturally producing harmonics in addition to the fundamental note - as well as the sound of the beater hitting the head.
Just about every sound in the world creates both a fundamental note and a series of harmonics. Cut-out the harmonics from a cello and an electric bass, and the note sounds identical. Pretty cool eh? It’s the harmonic series generated by the unique instrument that defines its sound.
But there is more than just math going-on here, the actual sound of these harmonics are generally very different. While even harmonics tend to make a tone smooth and warm, odd harmonics tend to add edge and clarity. Too much even and your tone becomes flubby. Too much odd and your tone becomes gritty, and not in a good way.
This is why most professional guitarists who employ a lot of gain and distortion use tube amps. Because when you start clipping odd harmonics, your now crispy and edgy tone becomes like a toothpick in your ear.
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