Intro: How to record Acoustic Guitar
How do you record an acoustic guitar? How do you skin a cat? These riddles have a myriad of answers. This post is here to help you find some guide posts to the first question.
Hopefully after reading this, you might discover your own method for recording acoustic guitar. I’ll talk through some favorite methods and discuss a few ideas you might want to consider before you embark on your journey.
Each section overviews a recording technique followed by the audio result of that technique. Headphones are definitely recommended when listening to the examples below.
I make a few assumptions in this post. Factors that make a big difference in your final result such as how the guitarist plays, picks and fingernails, and which guitar you choose are left up to you.
The Classic Position
To record acoustic guitar with one mic, place your mic at the 12th fret, 12 – 18 inches away, aiming in the direction of where the neck of the guitar meets the body. This can be any kind of mic, but a small or large diaphragm condenser is recommended as a starting point.
Your recording conditions will always be different, so adjustments will be needed.
First, adjust the distance to taste. Too close will give you a recording of only one part of the guitar, too far away will lack presence.
Next, play with moving the direction of the mic. Aiming more toward the body will give you more body and depth in the tone. Aiming up the fretboard will give you more attack and brilliance.
Keep in mind as you make your adjustments:
- The entire guitar emanates sound, not just the sound hole.
- Slight adjustments can make a big difference.
Your mix will determine whether you want to use one or two mics on the acoustic guitar. When you’ve got loads of other instruments and vocals to accommodate, stereo miking your acoustic guitar might be overcomplicating things.
One mic will suffice for acoustic guitar recording on a lot of mixes, but with two it gets fun. Stereo miking might be worth your time in mixes where the acoustic guitar plays a prominent role.
When you add a second mic, not only do you have a nice stereo image but you also give yourself more colors to work with and more ways to balance the sound.
Because a single mic can only point in one direction, it is limited to the sound that area of the guitar makes. If you back the mic away or use an omnidirectional mic, you have to include the sound of the entire room.
The following techniques take in the whole sound of the guitar without having to rely on a perfect room.
Before we get into the two-mic techniques, it’s worth discussing one of the most common problems when recording with two mics: mics out of phase.
How to Avoid Phase Problems
Phase problems occur when you have two mics on the same instrument picking up the sound from different distances away.
As a result, the waveforms on the tracks of each mic do not align in a pleasing way. The valleys of one mic’s waveforms are occurring at the same moment that the other mic peaks. This results in an overall weak signal or even silence!
The basic rule is to keep the mics the same distance away from the source. If you live by this rule, phasing issues are a rarity.
Engineers talk about the 3:1 ratio as a good rule of thumb to avoid phasing. This means that if you would like your source to be 1 foot away from the mics, the mics should be 3 feet apart.
If you would like the source to be 2 feet away, keep the mics 6 feet apart, and so forth, holding to the 3:1 ratio. But to be honest, I see engineers break this rule quite often without out-of-phase problems.
Two-mic Techniques: One at 12, one above the sound hole
In this method, a small-diaphragm condenser (Beyerdynamic MC 930) is placed at the 12th fret pointing to where the neck meets the body of the guitar. This picks up the attack and brilliance of the instrument.
To add some body to the sound, we have a large-diaphragm condenser mic (Neumann TLM 102) aligned level with the top of the guitar pointing above the sound hole. This gives us the body sound.
Comparing the single mic method above to this, you can hear how the guitar is not just making sound in one spot. How nice it is to hear the whole guitar!
Two-mic Techniques: One at 12, one on the bridge
In this technique, the small-diaphragm condenser (Beyerdynamic MC 930) is placed at the 12th fret, this time pointing at the picking hand of the guitarist. We adjusted the direction to get a slightly fuller sound from this mic.
The large-diaphragm condenser (Neumann TLM 102) this time moved to the bridge position, pointing between the bridge and the sound hole.
In this case, the TLM 102 in the bridge position is giving us some lower end and a bit of distance to the sound, while the MC 930 is giving us immediacy.
The two tracks add up to a balanced stereo image of the guitar.
Two-Mic Techniques: The X – Y STereo
This is the most common technique for stereo miking, the x-y or coincident stereo technique. A matched pair of small-diaphragm condensers (Beyerdynamic MC 930) are placed as close to each other without touching, at a 90-degree angle, pointing in opposite directions.
The stereo image with this technique is not as wide as what we hear in real life, but you can get a good sound, it’s easy to set up, and it’s a great way to avoid any phasing issues.
The two MC 930s are giving us an honest take on the guitar, without the larger-than-life extra that the large-condenser brings to the mix.
Recording Techniques Aimed at Getting a Particular Sound
The Singer-Songwriter Sound
For this sound, we used the ‘one at 12, one on the bridge’ setup featured above.
This setup allows for a wide stereo image. The mics are panned left and right leaving a nice gap in the middle for vocals.
A UA 610-B preamp, EQ with the Pultec EQP-1A plugin, and a tiny bit of compression with an LA-2A were slapped on for a quick singer-songwriter sound.
Blues / Roots Sound
To get some grit in the sound, for this set up we put a Shure SM57 at the height of the guitar pointing above the sound hole. The Neumann TLM 102 gives us some detail at the 12th fret pointing to where the guitar neck and body join.
On a side note, for a lot of mixes, an SM57 on acoustic guitar is a totally usable sound. Don’t underestimate this beast.
A UA 610-B preamp, EQ with the Pultec EQP-1A plugin and a tiny bit of compression with an 1176 was slapped on for a bluesy sound.
Pop / Rock Sound
For denser mixes, you need blade from an acoustic guitar – not something the instrument naturally lends itself to.
A dynamic mic like the SM57 or even dirtier, something like a Shure 520 DX, or the Superlux D112C will give you cut and color. In this take, we used an SM57 at the 14th fret pointing to the area where the neck meets the body of the guitar.
Paired with a large-diaphragm condenser placed at the 12th fret pointing in the same direction, we have a stereo image with detail and cut.
EQ with the Pultec EQP-1A plugin and compression with an 1176 were added for a quick pop sound.
Considerations when Recording Acoustic Guitar
The mic you choose should be based on the sound you need in your mix.
A small-diaphragm condenser will typically give you the truest version of your guitar with a lot of detail. Great small-diaphragm mics to experiment with include:
A large-diaphragm condenser will give you more bottom, rich detail, and a little larger-than-life acoustic guitar sound. Some good options for acoustic guitar recording include:
A dynamic mic will typically give your acoustic guitar some grit and character. Some great mics to try out for this include:
A ribbon mic will typically give you a less-harsh, warm-sounding guitar. Ribbon mics always have a figure-8 pickup pattern, which helps for old-timey sounds. Good ribbons for acoustic guitar include:
See here for more information on how microphones work.
The room you record in is especially important when recording acoustic guitar. The sound reflection of the instrument off the walls of the space you are in is part of what our ears recognize as the sound of the acoustic guitar.
Without this bounce, recordings feel lifeless. It is possible to close mic acoustic guitars or use the DI input only, but consider finding a space with a pleasant acoustic ambiance.
It may take some bargaining, but try to secure the largest room in your house for recording.
If you need to make do with a small boxy room, experiment with screening the reflections. Blankets do wonders! A large laundry drying rack with a blanket hanging like a wall is a sound shield I’m sure most people can manage to whip up.
When trying to fit the acoustic guitar into your mix, fix what’s not working first before boosting frequencies to flatter the sound.
Here are some guidelines that might help you find the sound you’re looking for:
- Cut the lows with a high pass filter if you don’t need much bottom in your mix from the acoustic guitar. In most mixes, anything at the bottom end will just clash with the kick drum or bass. Start around 150Hz taking away more or less bottom to taste.
- If things sound boxy, remove a bit in the 400-600 Hz range.
- If you have too much attack, remove a bit from the 3-6 kHz range.
- Use your ears, not your eyes.
What Gear we Use in These Examples
We recorded using Logic Pro X, an Apollo Twin X interface, and the following mics:
- Large-diaphragm condenser – Neumann TLM 102
- Small-diaphragm condensers – Beyerdynamic MC 930 (matched pair)
- Dynamic mic – Shure SM57
There was nothing in the signal chain, no compression or EQ, except where specifically stated. The guitar is a 1996 Martin SP000-16TR with new 80/20 bronze strings.
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