How to Mic a Guitar Cab: A Practical Starting Point
To mic a guitar cab, start with one dynamic microphone a few centimeters from the grille, pointed at the speaker, and move it until it sounds right. Toward the center of the speaker is brighter, toward the edge is warmer and darker. Small moves make a big difference, so listen while someone else plays, or record short takes and compare.
Start with one close mic
A single dynamic mic close to the speaker is the most common way to record or amplify a guitar cabinet. It handles high volume well, picks up little of the room, and gives a direct, focused sound that sits easily in a mix.
- Find the speaker. Use a flashlight to see the cone through the grille cloth.
- Place the mic one to five centimeters from the grille, pointing straight at the speaker.
- Start roughly halfway between the center (the dust cap) and the edge of the cone.
- Play at the volume you'll use for the take and listen through good headphones in another room, or record a short loop.
How mic position changes the sound
Center vs edge
Pointing the mic at the center of the cone gives the brightest, most aggressive sound. Moving it toward the edge gives a rounder, darker tone with less bite. Most good positions are somewhere in between, and a centimeter or two can change the character noticeably.
Distance
Closer means more low end, due to the proximity effect of directional mics. Further back gives a more natural, slightly roomier sound with less bass boost.
Angle
Angling the mic off-axis, so it doesn't point straight at the cone, softens the high end. This is a simple way to tame harsh treble without touching the EQ.
Multi-speaker cabinets and mixed speakers
In a 2x12 or 4x12, the speakers don't sound exactly the same. Try each one with the same mic position and pick the one you like best. That speaker becomes your recording speaker.
Some cabinets combine two different speaker models on purpose. The current Kool 2x12 cabinets pair a Celestion G12M65 Creamback with a Celestion G12H75 Creamback: left and right in the light weight 2x12, top and bottom in the vertical 2x12. With a cab like that, mic each speaker separately and listen. One may suit a clean part better and the other a driven part. You can also use two mics, one on each speaker, and blend them.
If you're choosing a cabinet with recording in mind, 1x12 vs 2x12 vs 4x12 explains how size affects the sound.
Miking an open back cabinet
An open back cabinet sends sound out of the back as well as the front. That gives a wider, more open sound in the room and some extra options when you record. All the current Kool cabinets are open back. The vintage open back 1x12, for example, has a tuned, oval-shaped open back.
- Front mic only: works fine and is the simplest starting point.
- Front and back mic: a second mic behind the cabinet adds low end and body. Because the back of the speaker moves in the opposite direction, flip the polarity (often labeled phase) of the back mic in your recorder or mixer. Without that, the two mics partly cancel and the sound gets thin.
- Placement in the room: keep an open back cabinet away from walls that are very close behind it, or use that reflection on purpose for more low end.
Open back vs closed back cabinet explains the difference in sound in more detail.
Adding a room mic and checking phase
A second mic one or two meters away captures the room. Blended in quietly under the close mic, it adds depth. Keep it low in the mix at first; too much room can make a guitar sound distant.
Whenever you use more than one mic, check phase. Listen to the mics together, then flip the polarity of one. Whichever setting sounds fuller and has more low end is the right one. A useful rule of thumb is to keep a second mic at least three times as far from the first mic as the first mic is from the source, to reduce phase problems.
You don't have to record loud for a good sound. The amp just needs to sound good in the room at the volume you play. If you record at home, tube amp at low volume has tips for getting a full sound without waking the neighbors.
Next step
Looking for a cabinet that sounds good both in the room and on a recording? Take a look at the Kool cabinets, or contact Kool to talk about the right cab for your amp and studio.