There are many different microphone placement techniques that can be used when micing up a guitar cabinet. Close micing, ambient micing, micing the back of the cabinet, and reamping are all very popular. Not only are there many different ways to mic a guitar amp, there are many different microphones that can be used as well. Even still the type of microphone that you choose to use could impact your placement on the guitar amp.

Hands down the most popular of all microphone placement techniques is close mic placement. Close mic placement traditionally is uses a dynamic microphone selection and allows the microphone to hear exactly what is coming out of the speaker without allowing the surrounding conditions to color the sound the microphone is picking up. Dynamic microphones can withstand a much louder SPL, or Sound Pressure Level, than a condenser so it make sense that they are used more frequently when putting them in front of a very loud guitar amplifier. If the guitar amp speaker is not a great sounding speaker, you might find yourself just not liking the way it sounds at all.

A few things that you can try in this situation is to first change the microphones axis point in relationship to the speaker. By this I mean that when you set the mic in front of the guitar amp you probably pointed the head of the microphone directly at the amp. Off axis mic placement is the technique of changing the angle at which the microphone is being directed at the audio source. Try pointing the microphone at a 45 degree angle instead of pointing right at the speaker. Of course the alternative is to try a different microphone as well.

Another mic placement trick is to add a 2nd microphone to the amp. This can be an additional dynamic microphone that is on a different axis point than the first and it is almost always a different kind of microphone. It is also very popular to put a large diaphragm condenser microphone some distance away from the amplifier and use it as a room mic, or an ambient mic. This allows that microphone to capture the nature reverberation of the room and create a more realistic sounding guitar tone. It is not uncommon at all to actually use the ambient mic as the only microphone source in a recording. This would be more for genres like jazz, blue, R&B, and perhaps some country. Although most home recording studios don't have great sound rooms, if you try using your bathroom or perhaps a your garage you can get some good ambient sounds in these areas. Large livingrooms with vaulted ceilings are great!

If you are using an open back amplifier this offers even more mic placement options as it is possible to add yet another microphone at the back of the amplifier pointed at the speaker. Close micing the back of an amp will normally sound much darker and perhaps “muddy” sounding compared to the front of the amp. This will not be the only microphone sourced used to get your guitar tone but if you blend it properly with the other microphones that are in the front of the amp it is very possible to get some great results using this method. Just be sure to not use too much of a muddy sounding microphone in your blend. It's really just for texturing.

Reamping guitars is the process of using a pre-recorded guitar track and rerouting that track out of your recording device through a reamping guitar direct box, and then back into the input of a different guitar amplifier. This is a great method to getting lots of really cool guitar tones without the guitar player having to stand in the recording booth for hours as the recording engineer tweaks and tweaks until they find the desired tone. Just be sure that if you want to use this method you plan ahead before you record the guitar track. Be sure to get a clean version of this. You do not want to reamp an already distorted guitar track.