Harnessing the Power of Feedback

Feedback may not be something FOH engineers want to deal with, but it’s a well of creative potential for guitarists. It’s not a new concept – guitarists have been tapping that well since the amp was invented, but it’s still a great way to transcend boundaries, evoke new textures, create atmospheres, and find new tone – without any new tools.

Defining Feedback

First, let’s define feedback in this particular context. Here, we’re talking about the controlled manipulation of amplified sound to produce sustained, harmonic-rich tones by placing a guitar's pickups near its amplifier, creating a feedback loop that enhances expression and enables the creation of unique and ethereal musical effects.

In other words, making the amp squeal by manipulating distance. Creating feedback almost becomes like playing the theremin in a sense. Dang near everybody experiments with feedback, but a few guitarists specifically known for it include Jimi Hendrix, Kevin Shields (My Bloody Valentine), and Thurston Moore (Sonic Youth).

Controlled Feedback Techniques

Next, let’s review the basic techniques for making feedback happen and controlling it. For newer players, this part can serve as a reference, and for experienced players, it can be a quick review:

• Positioning: Stand in front of the amplifier, facing it, to start it feeding back. Boom.
• Guitar Proximity: Bring the guitar close to the speaker cabinet to initiate feedback and move it further away to control sustain. Use your feet, body, or hands to manipulate distance and angle. You can swell, fade, and turn it off simply by moving.
• Quieter Amps: Feedback isn’t just created with raw volume. If you can’t go as loud, overdrive will make feedback more likely.
• Harmonic Nodes: Find the sweet spots on the strings (harmonic nodes) that resonate and sustain feedback – some notes will ring out like crazy and some won’t. Be aware that the room could play a part in which notes resonate more.
• Amp Settings: Adjust the amplifier's gain, volume, and tone controls to influence the feedback intensity and tonal qualities. Obviously, the whole rig has to be loud enough to resonate the strings or nothing will happen. Also, you’ll get a different feedback character from a super overdriven amp than a clean, loud signal – and everything in between. Also, don’t forget crank the guitar itself to eleven too, at least as a starting point.
• Vibrato and Bending: You can use note bends and/or your whammy bar, if you have one, to twist the feedback around and create cool new sounds.
• Use Effects: The cool thing about feedback as an artistic tool is you don’t have to add pedals to use it. But, that doesn’t mean you can’t enhance and shape your feedback with pedals like reverb, delay, and modulation – just beware that some effects (reverb and delay especially) can make the loop spin out of control fast.

When to Use Feedback on Stage

Obviously, you’re not going to play the whole show in all-out feedback mode (unless maybe you’re The Mars Volta). Here are some ideas when you might incorporate some feedback:

• Solo Sections – Obviously!
• Transitions: Using feedback during song transitions can create a seamless flow between different sections and build anticipation for the upcoming segment.
• Endings: Ending a song with a sustained feedback note can leave a lasting impression and create a sense of drama.
• Build-ups: Gradually introducing feedback as part of a buildup can intensify the tension and excitement before launching into a climactic moment.
• Emphasis: Employing feedback to emphasize specific lyrics or musical phrases can draw attention to essential elements of the song.
• Experimental Segments: In more experimental or improvisational parts, feedback can be used to explore unique and unpredictable soundscapes. Say in a prolonged avant-garde moment at the show’s start or during a singer/drummer/bassist break, etc.
• Interactions with Audience: Engaging with the audience by incorporating feedback into call-and-response moments can create a sense of connection and involvement.

Recording with Feedback

You can, of course, harness feedback in the studio too. You may have to experiment a bit with mic placements to capture what you want, and the room acoustics will be wildly different from your typical live venue, so leave time to play with it before you have to roll tape. But, although it’s a different environment than on stage, it’s a good place to experiment with gear.

Some gear and technique tips that apply in the studio and on stage:

• Single-coil pickups and hollow-bodied guitars tend to generate more feedback.
• For solid bodies (most electrics!), making sure the guitar is as rigid as possible (tighten screws on bolt-on neck, etc) will increase sustain and thus feedback.
• Higher gauge strings vibrate longer, meaning they need less feedback from the amp to ring out.
• Lowering the pickups so the poles are farther from the strings will increase feedback (but reduce drive to the amp).
• You can set up an instant feedback switch with a pedal like gain or compression, so you can turn it on and off quickly.
• A wah-wah is another good way to dial in a specific feedback frequency and fade it away at will.
• If you’re playing with the band, you may want to use strategic gobos to reign in spill, especially when you really wail on the feedback.
• There’s no reason you can’t layer multiple feedback takes and do things in the mix like pan them left/right or fade them in and out over time.
• Protect your ears – you’re generating a tremendous amount of high and mid-high energy (the kind that ears loathe) and you have to be standing in there to do it.

 

Feedback is no bueno for the house sound engineer and a nightmare for vocalists. But guitarists love it! When you learn how to control it, you basically transform the instrument and give it a wider pallet. But it takes practice just like regular playing. Be prepared to get it wrong for a while, but don’t be afraid to experiment. Happy playing!

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