Amp Miking Techniques for Guitar Recording

Microphone technique separates adequate guitar recordings from exceptional ones. The same amplifier and player combination produces vastly different results depending on microphone selection, placement, and the recording environment. Mastering these techniques provides the foundation for capturing guitar tones that translate across playback systems.

Understanding Speaker Behavior

Guitar speakers behave differently across their surface area. The dust cap at the center projects high frequencies directly forward, creating a bright, focused sound. The outer cone area produces a warmer, fuller response with reduced high-frequency content. The surround where the cone meets the frame adds a looser, more diffuse quality.

Speaker breakup characteristics vary with position. The center of the cone handles high frequencies but can sound harsh at high volumes. The edge of the cone provides smoother breakup but may lack definition. Finding the optimal position often involves placing the microphone between these extremes.

Multiple speakers in a cabinet respond differently. Manufacturing tolerances mean each speaker has slightly unique characteristics. Testing each speaker individually with headphones reveals which speaker best matches the desired tone. Many engineers develop preferences for specific speaker positions in 4x12 cabinets.

Close Miking Fundamentals

Close miking places the microphone within inches of the speaker grille. This technique captures the direct sound with minimal room influence, producing a tight, focused tone. The proximity effect of directional microphones adds bass when positioned close to the source.

On-axis placement points the microphone directly at the speaker cone. This position captures maximum high-frequency content and transient detail. The sound tends toward brightness and aggression, useful for cutting through dense mixes. Many rock and metal recordings rely on on-axis positioning for clarity.

Off-axis angling tilts the microphone relative to the speaker. A 45-degree angle softens high frequencies naturally without requiring equalization. This technique reduces harshness from heavily distorted tones and can add dimension to the recorded sound. Experimentation with various angles reveals optimal positions for specific amplifiers.

Distance and Room Interaction

Increasing the distance between microphone and cabinet introduces room acoustics. Even a few inches of additional distance changes the balance between direct sound and early reflections. The room’s acoustic characteristics become audible, adding depth and spatial information.

The three-foot rule provides a starting point for room interaction. At this distance, the sound has traveled long enough to develop, while remaining primarily direct. The tone feels more natural and less compressed than extreme close miking. Many classic recordings used this moderate distance.

Far-field miking captures significant room ambience. Microphones placed 6-12 feet from the cabinet record the sound as it exists in the space. This technique requires a good-sounding room but provides irreplaceable depth and realism. Combining far-field with close microphones offers mixing flexibility.

Multi-Microphone Approaches

Two-microphone setups expand tonal possibilities. Combining a dynamic microphone for midrange focus with a condenser for extended frequency response captures a complete picture. The Shure SM57 paired with a Royer R-121 represents a classic combination used on countless recordings.

Phase alignment becomes critical with multiple microphones. Different distances from the sound source create timing differences that cause phase cancellation. Using a phase correlation meter or flipping polarity while summing to mono reveals problems. Physical measurement ensures microphones remain equidistant from the speaker.

The 3:1 rule minimizes phase issues when using multiple microphones. The distance between microphones should be at least three times the distance from each microphone to its primary source. This ratio reduces the level of the bleed signal enough to prevent significant phase problems.

Environmental Considerations

Room treatment affects miked amplifier recordings significantly. Reflective surfaces behind the microphone create comb filtering as reflected sound combines with direct signal. Absorptive panels placed strategically reduce problematic reflections without completely deadening the space.

Amplifier positioning in the room influences the captured tone. Corners reinforce low frequencies through boundary loading. Wall proximity affects bass response and early reflection timing. Elevating the cabinet reduces floor reflections and places the speaker at ear level for more accurate monitoring.

Isolation requirements depend on the recording situation. Gobo panels provide partial isolation in open rooms. Separate isolation booths allow simultaneous recording of multiple instruments. In home studios, recording during quiet hours and using isolation cabinets often prove necessary for achieving usable results.