The process of recording and mixing acoustic instruments can be intimidating to producers that work predominantly in-the-box, but there’s really nothing to be nervous about.
The key elements of an acoustic instrument are the same as anything programmed or sampled. There’s a performance that is one of the most important parts of the track. There are the dynamics of the instrument itself, the space around it, and the technique used to capture the audio.
With the core of your acoustic performance boiled down to just those few elements, it’s easy to get a good sound with a bit of intuition and a great sound with a bit of preparation and practice.
Setting Up For An Acoustic Recording
In order to get ready for an acoustic recording session, you should prepare the musician as much as the space you’re recording in. If possible, acoustic instruments should arrive to the studio with fresh strings well before they’re recorded.
The sound of an acoustic instrument is more susceptible to change in a new environment even more so than an electric one. Bringing it in early and getting it out of its case allows the acoustic instrument to acclimate. You’ll end up with a sound that’s not only in tune, but fuller and richer as well.
The fresh strings are necessary to maintain bright and clear notes as well. Over time, strings tend to build up with grease and dirt from use. They begin to slowly oxidize and rust from the moment they’re played. This all adds up to dull, lifeless strings that sap away at the natural overtones your acoustic instrument offers. Starting with new strings at the beginning of the session, and changing them as needed throughout will make sure you get the most of your time in the studio.
Acoustic Microphone Placement
When you’ve got a great sounding space to record in, capturing as much of that in your acoustic track as you can really adds to the feel of the performance. Nothing beats a great natural reverb from the source if you can capture it. If you’re in this situation, a large diaphragm condenser backed 2’ – 3’ off of the instrument can capture an awesome balance between the instrument and the room.
On the opposite end of the spectrum, there are plenty of times where you won’t want the room in your acoustic recording at all. To achieve isolation, a closer recording technique is needed. Often engineers will use a small diaphragm condenser a few inches from the 12th fret, and supplement with a large or small diaphragm condenser capturing the body.
A small diaphragm recording the body is less susceptible to proximity effect, meaning you’ll often get a thinner, more controlled sound. Large diaphragm condensers are likely to respond a bit more to the dynamics of the instrument and create a fuller bodied tone. Just be careful that the fuller body doesn’t become boxy or boomy – if it does, backing the mic off a bit or adding a hi-pass filter can clean things up pretty well.
Once you’ve got a sound you like, it’s up to you whether you want to blend the two mics down to a single mono track or keep them as a stereo image. If you choose the latter, you’ll want to be sure everything is in phase.
Mixing Your Acoustic Instruments
For as great a sound you can achieve during tracking, everything can change when you reach the mixing stage of the process. What sounds great in isolation can sound super dense or overpowering in the mix.
Fortunately, as we said in the beginning, the elements of the track don’t change just because an instrument is acoustic. The mix is where you get to apply what you already know about mixing to not only make your acoustic track more manageable, but a sound that catches your listener’s attention.
Using EQ is almost always necessary when mixing acoustics. For acoustic guitars, it’s usually a combination of boosting low-mids where you need body, but cutting in the same range where it sounds boxy. You may also need to boost the high frequency content to add some air, but cut any annoying overtones. Mixing acoustics is about finding a balance between additive and subtractive EQ decisions.
Of course, it doesn’t stop there. Acoustic instruments are some of the most exciting candidates for dynamic processing. They take compression and limiting very well, both of which can bring out some unexpected, unique results. Don’t be afraid to use some extreme settings here – they can really help an acoustic instrument cut through a dense mix.
Finally, if your acoustic wasn’t recorded in the best environment, you can always replicate the space around in that you wanted using reverbs and delays. Using these time-based effects can help add size to your acoustic performance or give it a vintage vibe using tape delays like Soar.
Where Do Acoustics Fall On Your List?
Depending on the song and genre, your acoustic tracking might be one of your primary instruments to focus on. For others, things like drums, electric guitars & programming might take center stage. Knowing how to be quick and flexible, regardless of the situation, is what makes a versatile engineer so valuable.
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