In this age of home recording there are a lot of players experimenting with getting a big phat guitar sound in their own mixes. Someone on tight budget asked me today what type of mic they should use for recording their guitar amplifier. So, the question is: “I want to get a big sound recording my electric at home, what should I do and what should I use and what is the best deal?” Before we answer this question let me say right off the bat that I am not an engineer, I am a guitar player and musician so this article is not going to be replete with numbers and graphs and long words, except for some that we will need.
A Dynamic Cardioid is the most common of all microphone types. It works on a simple principle of turning sound pressure into an electrical signal via a diaphragm, voice coil and magnet. These are the same microphones that are used for live vocals and guitar amp miking in most stage applications. The two most well known models are the ubiquitous Shure SM 57 and SM 58. Both of these mics use the same dc technology and have become industry standards. The fact is that now there are many other options that will provide a comparable result on a very low budget.
Core Characteristics of the Dynamic Cardioid Mic
- A tight directional pickup pattern
- Ability to handle high SPL (sound pressure levels)
- Frequency spectrum appropriate to the task.
The Pickup Pattern
First off, the word Cardioid actually refers to the pickup pattern of the microphone. It is a small tight close proximity pattern that is ideal for feedback rejection. You may have noticed or used mikes like this for vocals in the past where you had to get in close to the mic to get a big warm response. Notice how experienced singers position their mikes, close to or touching their lips, this is where the mic is designed to have the best response. If placed only slightly too far out of axis the bass response and overall db (decibel) level drops dramatically. This common vocal mic positioning effectively demonstrates the tight pickup pattern characteristics of a dynamic cardioid.
This also means that when miking your amp you should get the mic in tight to the speaker, don’t think of the cabinet but think of where the speaker is sitting within the cabinet and imagine miking the speaker, not the cabinet. Also, don’t hang the mic off the amplifier because this will limit your ability to direct the mic to its optimal position. Put the mic on a stand with a boom that will give you the most flexibility for movement and placement. This tight miking technique will eliminate the sound of the room which for most home studio applications is a good thing. It allows a cleaner signal to which you can add your own desired reverb and room settings with digital processing.
Another real benefit to the dynamic cardioid mic is that they wear very well and are not touchy when it comes to handling as some high priced condensers are. It is a simple functional design that handles a lot of SPL up close and that is exactly what you want if you are looking at cranking your amp in a sound booth type environment. This mic design is unlikely to break up even at higher levels. This means that the mic won’t create its own distortion and because of this it will allow you to eliminate variables when trying to find the sound you are looking for out of your guitar and amp.
The Frequency Spectrum
The Frequency Spectrum of a mic usually comes with the packaging when purchasing and looks something like this:
This is a frequency spectrum of a typical dynamic cardioid instrument mic. If we were to compare the frequency spectrum of the source, being in this case an electric guitar and amp it would fall well within the range of the microphones capability of picking up the full spectrum from the amplifier and guitar. For our purposes here this is not a technical study of acoustical physics and all of its attendant variables. For almost all applications this frequency spectrum will give you lots of room to get a great sound from your guitar and amp. To put it another way, this mic design has been used to mic amps on some of the most well known recordings of all time.
Most of the microphones in today’s market are manufactured in Asia and as a result the cost for excellent quality mikes has come down to a fraction of what they were a couple of decades ago. Two mikes that I would suggest are the Samson Q7 as well as the Audio Technica MB 2k/c. These microphones retail at between 40 and 80 dollars and I have done A – B comparisons between more expensive mikes and they are without a doubt excellent choices with excellent characteristics for this job.
At prices like this I would suggest getting two so that you can get a stereo signal in your mixes. Make sure to place the gain on your guitar at 10 and then adjust the volume of your amp where it suits you best for the tone you want. With a stereo mix with two mikes it allows you to pan left and right thereby giving you a real stereo guitar sound. If you want to go one step further than this, double the same guitar track and you now have 4 guitar tracks, but, they have to be played perfectly and identically to achieve the desired huge result.