This column will discuss some of the ways that you can get different tones out of your bass. There are several simple things that you can do to change your sound, sometimes right in the middle of playing. I’ve broken them down into two main groups: Fingering and Controls. I have put all of the technical discussion at the end.
You can change the way your bass sounds just by how and where you play the strings. Here are some simple examples. You should set your tone controls to their brightest settings for this (usually fully clockwise).
Play an open D string. Now play the same D note on the 10th fret of the E-string. Note that they sound very different. First, if you plucked the string with the same force each time, the E-10 D was likely to be louder. Second, the E-10 D should have sounded “smoother” or “rounder” or whatever term you like to describe having less overtones. Playing above the 7th fret will always sound different than playing below the 5th fret. The higher you go, the smoother it sounds.
Next example: Play the same D on the 5th fret of the A-string. Pluck the string with your fingers over the bottom of the neck. Now continue to play while slowly moving your plucking fingers way from the neck, toward the bridge. You should hear the tone change from “round” to “bright”. I like and use this effect so much that I installed a continuous thumb-rest on my fretless; it goes all the way from the neck to the bridge.
See, you’ve made significant changes to your tone without touching any knobs on your guitar or amp.
If you play with a pick, you will add some “scraping” sounds as well as make the strings sound a little brighter. Playing with your fingertips deadens some of the highest tones.
Different string types can also change your sound. The technical reasons are discussed below, but the simplest rule is that flat-wound strings sound – well – flat, while round-wound strings are generally brighter. Different brands make different claims, but it’s not just hype, they really do sound different.
You can also change the tone significantly by “slapping” or “popping” the strings. These techniques move the string vertically and force it to hit the frets, which creates all sorts of higher tones. The techniques for fast “slap and pop” playing are not what I consider beginner level, but you can play around with slapping low notes with your thumb (just bounce your thumb on the string, resting your wrist on the bridge) and popping some high notes with your index finger (hook the string and pull it away from the neck). Be careful, as both of these techniques can get loud unexpectedly.
In addition to the volume knob, most guitars have a simple tone control. Turning this control reduces the amount of high frequency sounds that are passed to the amplifier. Often you will turn down the higher sounds to produce a very mellow sound, or to reduce fret noise.
If your bass has two sets of pickups, then there will likely be two volume controls, or some sort of balance control. The pickup nearest the bridge detects more of the higher sounds, while the pickup nearest the neck detects more of the lower sounds.
And of course, your bass amp has some tone controls, which can change the sound as well.
Note that the tone controls on your amp and your guitar can’t really change the balance of high and low tones produced by the strings. They only control the balance between specific fixed frequencies, thus setting your tone control mid-way will make your higher notes rounder, but won’t affect the lower notes. The only way to change the sound that the string produces is to change the way you play it, as described above.
CAUTION – The following has been known to induce headaches in intelligent people!
As often seems to happen, David has written a column recently on a similar topic (guitar harmonics – Harmonic Convergence), and I recommend that you read it, just for the knowledge. In summary, every instrument creates overtones when you play it. Every environmental detail, large and small, affects the balance between these overtones (also known as harmonics). Each overtone is a multiple of the fundamental, so an ‘A’ note that has a fundamental of 440Hz (rate of vibration in cycles per second, called Hertz), and harmonics of 880 (also an ‘A’), 1320 (‘E’), 1760 (another ‘A’), etc. All musical instruments create overtones in differing proportions, that is why an oboe sounds different than a trumpet. The flute is usually considered the most “pure”, having the least amount of overtones.
As we know, sound is created by the string vibrating through air (or over a magnetic pickup). And we know that the shorter the string, the higher the note. But the opposite is true as well; the higher the harmonic, the shorter the “wave-length”, or equivalent string length. A string on a guitar (or piano, or violin) vibrates at all these different frequencies at the same time. When the balance between the fundamental and each of the overtones changes, you get a different sound. Unfortunately, it’s more complicated than that. For example, if you pluck the string exactly 1/3 of its length from the bridge, you will put more energy into the 4th, 5th etc harmonics, and a bit less into the fundamental, but no energy at all into the 3rd or 6th harmonics; you muted them with your finger – go figure. Here is a website that has a bunch of physics and math, but also has an animation that shows how it works.
As described at the top, when you pluck the strings closer to the bridge, your fingers are creating a shorter string length on one side, thus putting more energy into the overtones, and proportionately less into the fundamental.
Arrgggh! This sounds so technical!
The point is that the higher overtones occur at different places on the string, and so the amount of string movement differs at different places, which means that the pickups see a different balance of harmonics depending on where they are placed on the guitar. The classic example is the Fender Stratocaster: it has three pickups which you can select; the closer to the bridge, the higher the tone. The closer to the neck, the mellower the tone. If you select the middle pickup, you get almost none of the 4th harmonic from an open string! So it’s not just distance from the bridge, it’s the location relative to the harmonics.
This is why the ‘D’ played on the 10th fret of the E-string sounds “rounder” than the open-D. The higher harmonics are all still there, they are just not centered over the pickups, while the fundamental has moved to be directly over the pickups. A fair amount of engineering goes into the placement of the pickups to get the best balance of all the harmonics. It’s also why some bass guitars give you two pickups in different locations so you can shift from a “round” to a “bright” sound.
Fender makes two classic bass styles. The “Precision” (or P-bass) has two half-pickups grouped half-way between the neck and the bridge. They found the best place to put a single set of pickups. The “Jazz” bass has two pickups, one closer to the neck, and another close to the bridge. This allows you to selectively change the balance between the fundamental and the overtones. Different guitar makers connect and control the two pickups differently, but the added flexibility is what is desired. (Note: there are other differences between the P-bass and the J-bass as well)
It gets worse. The mechanics of a wound bass string are more complicated because the windings prevent the string from acting like a pure wire. It’s actually good that the heavy bass strings are made up of several lower gauge wires, as a single thick wire wouldn’t flex enough to generate the shorter wavelength harmonics. That’s the reason different string types sound significantly different. And when you play fretless, your fingertips reduce the highest harmonics but not the middle ones, which gives it a really warm feeling without sounding boomy.
Confused? Don’t worry about it. Just remember that almost any and all of the different tones you want can be created just by playing the guitar differently.
And then there are the effects boxes, which is another topic all together…
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