When you hear that distinctive shriek coming out of your amp, you may wonder what's causing all the feedback from your electric guitar. Guitar feedback is a double-edged sword. To guitar players in more controlled fields such as jazz, classical and mainstream pop, feedback is anathema, a problem that must be eliminated. For musicians who play certain forms of rock music, guitar feedback is just another weapon in your bag of tricks, a tool to be properly utilized. No matter if you take your guitar playing cues from Django Reinhardt and Les Paul or Thurston Moore and Lou Reed, you may still wonder what causes the whiny noise to come out of your amplifier.
Why Your Electric Guitar Gives Feedback
The feedback coming out of your amplifier only has one source. The tell-tale shriek is the result of the gain on your instrument being at too high a level. This causes the sound coming out of your amplifier to get picked up by the guitar pickup and fed back out the amplifier. To visualize the process, think of a snake eating its own tail. Equalizers exist largely for the sake of controlling the feedback emitted by any electrical instrument by making it possible to reduce certain high frequencies. Factors that will cause excessive gain to turn into feedback include:
- How far your guitar is from your amplifier
- Which direction the pickups on your guitar are facing
- Surfaces that reflect the sound from either the guitar or the amplifier in certain directions
- The presence of other instruments or amplification devices, such as guitars and microphones
Getting Rid of Feedback
For players who fall into the "clean guitar" camp, the reasons for electric guitar feedback are less important than getting rid of it. Understanding how feedback is created may help you to get rid of it, although a short checklist of things to do to get rid of feedback may be more useful.
- Change the position that your amplifier is facing. Facing the amplifier at an upward angle is particularly helpful, especially when playing in tight spaces.
- Move the instrument to a different position. Try facing the pickups on your guitar away from the amplifier.
- Adjust the controls on your amplifier. You can reduce or eliminate feedback by turning down the volume on your guitar or lowering the amount of distortion or overdrive that you are using. For the rock guitar player, the latter may come at the expense of the sound you are looking for, but it's better than the shriek of feedback.
Others who like the sound of feedback won't necessarily want to know how to eliminate it. Rather, they'll want to know how to control it. You don't have to be an aficionado of heavy, noisy guitar bands to want to use feedback. Artists like The Beatles have even used feedback in a controlled manner. A few tips on the proper use of feedback will get the beginner started, yet also give more experienced noisesmiths some theoretical knowledge.
- Tube amps are better than solid state amps for producing natural, controlled feedback. This is because solid state amps use a more advanced technology designed to get rid of things like feedback. High-gain guitar pickups can also make it easier for you to produce feedback.
- There are devices available that will make it easier for you to control feedback. These include the violin bow (and its guitar-oriented cousin, the ebow) and the sonic transducer.
- Spend a lot of time experimenting with your instrument and amp. Even the master of feedback, Jimi Hendrix, had trouble playing feedback precisely the same way more than once. This is because feedback is highly unpredictable and reliant upon a number of complex factors. Playing around with your instrument and your amplifier will give you a far better means of knowing how your specific guitar and amp combination work together to produce feedback.
The Place of Feedback in Music
Again, feedback is either a bane or a boon depending on which type of music you play. Artists such as Lou Reed have made entire albums of feedback while groups like Steely Dan have painstakingly eliminated all traces of feedback from their music. Using feedback with your electric guitar is more of an art than a science. It is imprecise and unpredictable. Removing the sound of feedback from your guitar, however, is simply a matter of checking all the potential trouble sources and addressing them in turn.