Without question, the electric guitar is at the heart of todays musical arrangements across all genres. Polished pop, indie rock, nu-metal, singer songwriter, country, jazz, and even hip hop employ electric guitars to bolster their arrangements. There is such a breadth of tone and style that can be produced with the electric guitar that it seems like their would be an infinite number of methods to record it. First and foremost it is helpful to think of the electric guitar as an electric instrument, generating current at the pickups, and amplified in several different ways. Most often, the signal is amplified by a big honking amplifier!
Guitar amplifiers and cabinets come in all shapes and sizes, and offer the ability to take the signal and tone generated at the pickups, and mold them with more tonality, distortion, and warmth. Further, the speaker in an amplifier colors the sound through the natural compression of the cone as it creates compressions and rarefactions that transmit sound through the air. Proper choice and placement of a microphone dictate the tonality of what is captured.
Microphone Choice and Placement
Due to high SPL (how loud an amplifier can get) many condenser microphones tend to be too sensitive for very close proximity recording of the speaker. For this reason, dynamic microphones like the famed Shure SM57 or Sennheiser MD421 are used in this up close and personal capture of the amp. Tonality (think EQ) can be garnered from choosing how the microphone is directed at the speaker (in sound engineer parlance, this is known as “on axis” ( microphone diaphragm facing source directly) or off axis (microphone diaphragm not facing source directly). The following figures show what mic placement angle is, and how it affects sound.
The tone of the microphone cabinet can also be dialed in by choosing proximity of placement. As you can see in the following diagram, bass response of the SM57 is greater the closer you get to the speaker. If you want to thin things out, you have the choice of moving the speaker off axis and backing it away from the speaker cabinet.
Ultimately the engineer needs to use his ears to decide what works best for the song, and this is done with a set of headphones, while the drummer is play in the studio, as he or she experiments with placement of microphone.
Many engineers will choose to further dial in tone by using a second or even third microphone to capture other characteristics of the speaker cabinet. Using a large diaphragm condenser microphone further away from the cabinet (several feet), can work well as an adjunct sound source. Care must be made that the phase relationship between these microphones is maintained.
Recording engineers also have another technique to capture the electric guitar, without a microphone. By using a DI (direct inject) box the engineer can plug a guitar directly into a microphone preamplifier. A DI box matches the impedance of the guitar coils to the microphone amplifier and sometimes removes noise. These boxes come in active (powered, with transformers), passive, forms, and can vary greatly in quality. This DI output comes into a microphone preamplifier, which can also mold the sound of the signal captured.
This direct inject signal can be processed in any way that the engineer chooses, after it has been captured. With amplifier simulator plugins, and other effects processors inside the DAW, the choices seem endless. Ik Multimedia’s Amplitube, Waves GTR, Two Notes Torpedo, and host of other plugins can create an overwhelming breadth of sound!
The signal recorded by direct inject can also be “reamped” by sending it out of the DAW back into another guitar amplifier (or many amplifiers) to record several different “versions” of the sound. You can conceivably hear what the guitar sounds like through 10 different amplifiers, each at 10 different settings, and all turned up to “11”, using this method of sending the signal back out of the computer, back into the guitar amp.
Ultimately there is no replacement for vision, experience, and the willingness to experiment with these techniques in the studio! Recording electric guitar can be one of the great joys of the recording process, especially when approached with good knowledge of technique, good tools, and a child-like inquisitiveness!
Do visit the Fish Tank recording studios in Miami, to record your guitar today!