PICKUP PLACEMENT ALONG THE GUITAR SCALE
Before your read this article we recommend you also read the one titled
Vibration of the string
which talks about nodes and anti-nodes.
First of all we have to consider that nodes and anti-nodes move along the scale as we play the fretted notes. So all below considerations refer to open notes: E, A, D, G, B, E for the guitar and E, A, D, G for the bass.
pickup placement along the scale is by far one of the most important factor to influence tone.
The position of the pickup on a Strat respect to the nodes and the anti-nodes of the various harmonics. The neck pickup is placed toward the middle of the string's vibration and will capture more of the fundamental harmonic which translates in a warmer tone compared to the bridge one which by capturing more of the upper partials will deliver a brighter tone.
As a general rule we can say that:
- the more the distance from each pickup the more variation of sound we will achieve on the instrument,
- The nearer the pickup to the center of the open string vibration i.e. the 12th fret the warmer the tone we will obtain with more volume and lows,
- the more the pickup will be near to the bridge the brighter the tone.
This is one of the reasons we hear a difference even while plucking the strings toward the neck or toward the bridge.
By studying how genius like Leo Fender and Lester Polfus (Les Paul) designed their instruments we have the chance to learn more on the importance of pickup placement for our tone.
As the first thing both of them thought to put the pickup as far as possible from each other to achieve the widest variety of tones possible and allow the player to pluck the strings with the pick easily.
Fender added some interesting options though.
As he planned to use single coil pickup which capture the vibration in a small portion of the strings, he decided to slant the bridge pickup bringing the upper part of it closer to the neck to capture some more lows end on the lower strings which acquired that way a warmer tone on this pickup.
Secondly, both on the telecaster and the Stratocaster which both originally had 21 frets,
he decided to place the neck pickup exactly under the node of the third harmonic where actually the 24th fret is on modern guitars.
Note he could place it stuck to the fretboard like LP did but he did not (please read here).
In this position the 4th harmonic of the open strings doesn't sound (see picture below).
In other words where Leo Fender placed the neck pickup on its Strat and Tele, some of the harmonics of the open strings are
NOT SOUNDING or are out of phase and this is exactly what contributes to that typical "twang" tone we all know and love.
Most probably Fender choose that placement just because he liked that tone.
This teaches us another thing. While calculating the neck pickup placement, Fender did base itself on the nodes and anti- nodes of the strings vibration by giving more importance to the two first harmonics (fundamental and second) than the other partials, as they were the loudest ones.
Finally the rules to consider when placing the pickup on your new guitar project are:
1) starting on the fact any placement consideration must be made on the open strings, 2) placing the pickup as far as possible from each others give us more sound versatility,
3) Arrange bridge pickup not to be too near or too far from the bridge to capture the right amount of brightness and warmth,
4) considering that the tones we are accustomed to are the result of choices operates by other many years ago and which along the years are now standards and therefore it's better to consider them seriously,
5) small moving of pickup toward the bridge will have a greater impact on tone rather than moving it toward the neck.
HINTS AND TIPS
This is something which gained me a lot of fans especially pros and jazz player and generally alternate pick players:
If the strings are not perfectly centered over the poles of the pickup there will be a difference in the tone when plucking the string up or down, in alternate picking.
This especially happens in the highest strings which have a lower influence on the magnetic field of the pickup and can therefore be placed closer to the pickup poles.
For this reason if you noticed that the poles spacing of your pickup doesn't perfectly match the one of the strings above, I suggest that you align the high E string rather that the low E string above the relative pole. Lower strings will sound perfectly because their vibration is wider and so is their influence on the magnetic field of the pickup pole, while the highest strings need a more precise alignment to sound correctly.