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Home Guitar Recording: How to Mic Up Your Amp

Home Guitar Recording: How to Mic Up Your Amp

Getting a great guitar sound needn’t be hard work…

When it comes to miking up a guitar amp there are many considerations to consider:

  • Which microphone to use?
  • What differences are there between microphone types?
  • What impact do microphone polar patterns make?
  • Where to place the microphone?

Microphone Types

Though we cover them in great details in a previous blog article, we’ll briefly run through Dynamic, Condenser and Ribbon microphones.

Dynamic

When it comes to all-purpose microphones, Dynamic mics are generally what spring to mind. They are suitable for vocals, recordings drums, guitar amps, anything. The reason for this is down to their robust build and ability to handle high SPLs (Sound Pressure Levels).

Without going too far down the rabbit hole of acoustics and what not, let’s just say that in reference to miking up a guitar cab, the higher the sound pressure level, the greater the level of intensity that that microphone is put under. So, if you crank the amp and stick a dynamic mic in front of it, chances are it will hold its own fairly capably.

They are also relatively cheap compared to other types of mic, which is never a bad thing. If you want to go really in depth, then check out our “What is a Dynamic Microphone?” article.

Top Dynamic Mic Shure SM57

Shure SM57 Cardioid Dynamic Microphone

Condenser

Condenser mics offer a bit more in the way of nuance across the frequency range, accentuating certain aspects of an instrument’s timbre that may be somewhat lacking from a dynamic mic. This is due to microphone sensitivity and the ability to capture greater detail across a wider frequency range. For vocals and acoustic instruments, they are much more favourable. They require Phantom Power, which in effect gives the signal a slight boost.

However, as condenser mics are more sensitive a less gung-ho approach needs to be taken when miking up a high SPL sound source like a guitar amp. Don’t just crank it and stick a condenser in front unless you want to break the mic – also, condensers tend to be more expensive than dynamics so unless you’re feeling flush be mindful of how you handle it. Greater care and consideration need to be taken with regard to mic placement.

Top Condenser Mic Rode NT1

Rode NT1 Condenser Microphone

Ribbon

If dynamics are the all-purpose workhorses, then ribbons are the thoroughbreds. Considerably more expensive but with good reason, they offer the highest standard of audio capture. However, they are more sensitive than condensers and to say that some need to be handled with care would be an understatement. One thing to note, vintage ribbon mics don’t need phantom power and steer clear unless you want to destroy the mic.

Why would you use them? Because, they sound amazing.

In the video below Tom points out that the Royer R121 is designed to handle high SPL and won’t necessarily be damaged by phantom power. If you feel like dropping some serious money on a mic then go for it.

What impact do microphone polar patterns make?

In terms of polar patterns, they can make a massive difference with record to the recording you capture. Every microphone has a unique polar pattern, which is the direction at which sound sources are captured.

If you want to imagine it another way, picture the beam on a torch pointed at a wall. The more focused the beam, the narrower the surface area of the wall that is illuminated. As you open the beam wider, then you can see more of the wall.

Polar patterns can be considered in the same way. If you use a mic that is highly directional, then you are going to narrow the focus onto the sound source. If it is omni-directional (picks up sounds from all around), then you’re going to pick up soundwaves coming from the sound source, as well as reflections of surface areas around the room, etc.

Cardioid patterns

In the simplest terms, Cardioid patterns are directional and pick up sounds from directly in front of them. Something like the SM57 is a great example of this, as you point the mic in the direction of the sound source, it will focus on that point. Super-cardioid and hyper-cardioid mics narrow the focus even further. If you don’t want to pick up any of the room sound, then cardioids are the way forward.

Omni-directional

Omni-directional mics are great for distance miking and picking up the sound in the room. Used in conjunction with a close-miked cardioid mic, a distance-miked omni mic offers a subtle ambient balance for a fuller picture of the amp’s response within the room.

Figure-of-8

This is where the mic captures audio from front and back but less so from the sides – hence it looks like a number 8 on a chart. In effect you can pick up the sound source directly, as well as the reflections of the sound bouncing back from the wall. For a bit of room ambience in the recording without using a two-mic setup, it’ll do the trick nicely.

Basic Microphone placement

When it comes to placement there are some recommendations that you can utilise to get off the ground.

Using a mic with a cardioid pattern:

  1. Point the mic towards the speaker that sounds that best. Might sound daft but chances are on a 2 x 12/4 x 12 cab there is going to a speaker that just sounds better than the other(s)
  2. Aim the mic at halfway between the centre of the speaker cone and its edge, leaving roughly 10mm gap from the edge of the mic and the speaker grille
  3. For a reduction in bass response edge the microphone back until you find a sweet spot
  4. To increase mid to high-end frequency response move the mic closer to the centre of the speaker cone.
  5. To scoop the mids move the mic towards the edge of the speaker
  6. Don’t be afraid to move the mic around – cab and mic setup responds slightly differently to each other. However, make the movements small as the distance between short distances can be vast

Handy Tip: If you have the option, run a loop through a pedal and play through the amp as you make adjustments to mic position. You can then get a real-time reference over changes to mic response.

The wizard that is Tom Quayle goes through all this and more, demonstrating the massive differences that mic type and placement makes in capturing your tone.

Have fun with it

There is no right or wrong when it comes to miking up your amp, except where it comes overloading the mic due to too high SPLs (unless you hate the mic and want to kill it…). Try out different mics and get creative with how you position them.

If you liked that, then you might like this

Get experimental after reading or guide on “Unusual Recording Techniques“.

If you want to dive deeper into the world of mic placement, then our article goes into whether it should be considered “Art or Science“?

For those who like to tweak their tone on-the-fly, check out our handy guide to “Reamping Your Guitar or Bass“. Tom Quayle guides you through the process that offers greater flexibility in the studio.

If you’re flummoxed as to how to get the best use out of your amp’s effects loop, then we’ve even got an article on that too. Believe it or not it’s titled “How to Use the Effects Loop On Your Amp(do you see what we did there?)

About The Author

Jon Whittaker

Jon is a multi-instrumentalist with a passion for inspiring others to get involved in making music. After spending many years playing venues here, there and - pretty much - everywhere, he joined the Dawsons' Music Web Team before progressing into his current role managing the Dawsons Blog.