Before we dig any deeper into what are the difference in construction and therefore sound between single coil pickups and humbuckers, it’s better to first explain the guitar anatomy and primary function of pickups since the days of their creation.
Single coil pickups were the first to be created. They’re purpose was to amplify the disturbance created by the movement of the strings of a guitar. The disturbance transferred to an electrical signal by the pickup, and affected by the guitar’s electronics, through the amplifier, becomes a vibration resulting in the sound of a guitar.
The main reason that trigger this change was the transition from smaller bands to bigger orchestras where the sound of the guitar got diluted among the other instruments and it needed to be amplified. Of course, as the era of rock and roll was born, these changes became an important tool that defined the sound of the instrument, secondary effect that no-one could have foreseen at the time of their creation.
How Humbuckers Were Born
Single coil pickups are magnets in essence, meaning wire wrapped around a series of magnetic poles. Over the years and the different guitar models, companies have experimented with these magnets, variations in the size of the pole pieces and in the number of wires, but all had the same basic problem.
These magnets can also behave like antennas, picking up all sorts of electromagnetic impulses (EMI), like power lines, amplifiers, speakers, distortion pedals, cell phones, and computers, and amplify them, causing a hum, sometimes very loud and noisy.
The humbucker pickups were initially created as a solutions for this particular problem. By using two pickups, meaning two single coil pickups together providing a higher signal, they cancel each other out, or should we say “they buck the hum”, reducing the electromagnetic interference that causes the noise, and creating a much quieter pickup.
Another effect than came out of this change in design, was a gaining more output, and distortion, which eventually lead to playing distorted guitar as a common practice.
How the Difference Affects the Sound?
Sound wise, is the traditional opinion that single coils, given the electronic explanation above, create a brighter quality of tone. Best for playing a cleaner sound. At the same time, is commonly accepted than the humbucker creates a warmer, and fatter sound, best for distortion.
However, there are countless examples of guitarists that play clean using Les Paul, which is undoubtedly the best known guitar with humbucker in the world, along with metal legends like Tommy Iommi or Ritchie Blackmore who play with single coil pickups.
One of the reasons for which the breach in the sound is not as wide as it could be, is that opposite polarities on multiple single coil pickups, like the ones on the Stratocaster, to give an example, can be use to prevent electromagnetic interference as well and buck the noise. And at the same time, be adjustable individually to customize the sound; therefore, giving the guitar a somewhat similar effect to humbuckers with a different kind of versatility in sound.