A DIY Acoustic Guitar Recording Primer
Let’s assume that along with releasing your music online, you’re also a budding recording engineer and would like to record your music with you as the acoustic guitarist. Here are a few tips that I’ve gathered in my years of doing exactly that. Like a lot of musicians, I tend to wear several hats in the recording studio. Along with engineering and production, I do a lot of my own acoustic guitar work. The issue here is that in order to effectively engineer and play acoustic guitar at the same time, I’m forced to record in the control room so that I can run my Pro Tools rig. Over time I’ve cobbled together an approach to help me get a clean, full and detailed acoustic guitar sound without using an isolation booth or bringing in another engineer.
As there are a lot of details to cover, I think it might be best to split this article up into two parts with the more technical information coming in part two.
To Plug In or Not to Plug In
While it may seem like the obvious way to go, I’m not a fan of using on-board pickups in acoustic guitars when I record. While it’s true that plugging in a 1/4” cable to your guitar and plugging the other end straight into your DAW will effectively remove all room noise from the recording, the sacrifice you make in tone is too great to justify. There are quite a few great-sounding piezo electric pickups on the market these days and when run through a live PA, they can sound full, clear and even woody. However, a large part of the sonic beauty of the acoustic guitar lies in the way the instrument pushes air out of the sound hole. A plugged-in guitar is only translating the vibration of the strings and loses the essential “acoustic” nature of the sound. On top of that, because acoustic guitar pickups are often designed with stage performance in mind there’s the likelihood of a slight hum or buzz which while unnoticeable on stage in a live venue can be extremely distracting when scrutinized in a studio recording. All this to say, unless you’re consciously going for the particular sound that a plugged-in acoustic guitar gives, avoid the easy way out and try a few of the tips I’m suggesting below.
Let’s face it; there is no trick or secret that can take the place of a quiet room for recording. So let’s start with the obvious. Do everything within your power to control the environment in the control room before you even get started. You might want to put up some sound absorbing panels on the walls nearest your set up. You can even go as far as to put sound diffuser panels on the ceiling above you. Essentially, you’re trying to deaden the environment closest to you so you won’t be recording a lot of room sound with your acoustic. While it’s fairly easy to add reverb to simulate different spaces once the guitar is recorded, it’s practically impossible to remove the sound of the room you’ve recorded in if it’s too present in the recorded sound. The one place I like a hard surface is the floor. There’s something bright and clear about the tone of the acoustic when the mic is picking up some of the reflections of the sound coming up off of the floor. Also, distance yourself as much as possible from your computer to minimize the volume of the fan noise. Of course, since you’ll be recording yourself, you’ll need to keep your computer within reach but you can always improve the odds by facing the microphone towards your acoustic and away from the computer. And speaking of microphones…
There are many, many microphone choices you can make when recording an acoustic guitar and each has its own merits. For my ear, a large diaphragm condenser mic set in a cardioid pattern and pointed at an angle where the guitar neck meets the body at a distance of about six inches works best. There are several reasons for this. First of all, I like the broader spectrum of tone I get when I use a large diaphragm mic as opposed to a pencil mic. Secondly, the cardioid pattern focuses the recording field which helps remove the questionable environment of the control room. Finally, by not pointing the mic directly at the guitar’s sound hole, you get the fullness of the tone without all the low mid “woof.” The proximity of the mic to the guitar also enables you to get a much higher direct sound to reflected sound ratio. As I mentioned above, make sure to angle the mic so that its back is toward your computer in order to minimize what is probably the loudest piece of gear in your control room. If you’ve got a bit more budget than most when you put together your studio, you can also consider some sort of isolation cabinet for your computer but it’s not essential.
After covering your set up, the room and mic choice/placement in the first half of this article, it’s time to get into the more technical issues of the actual tracking and subsequent use of EQ and effects.
Click Track Bleed
OK, now that your room is ready and your mic is placed, you’re going to want to take additional precautions to avoid the bleed of the click track sound from your headphones and into the mic. This is one of the most common mistakes people make when recording acoustic guitar to a live mic. My recommendation is to avoid high frequency tones like shaker or woodblock and consider a low tone like a sampled kick drum. Low frequencies don’t have the same piercing effect through headphones that most click sounds do. Also, once you’ve played the song through the first time, you can actually automate the volume of the click sound to lower in soft passages and drop out at the end of the song if there’s a ritard or a long sustain on the last note. There’s nothing that kills the mood of a song like the sound of a click track peeking through over the final chord.
Front End EQ/Compression
If you’re using a preamp and/or compressor between your condenser mic and DAW, there are a couple of things to bear in mind. If the mic pre has a high pass filter, setting the frequency to between 60hz and 80hz will go a long way towards minimizing control room noise. Also, while heavy front-end compression on acoustics can give the guitar a very present, powerful sound, I tend to avoid it in this scenario because it amplifies to a great degree the noise of the room we’ve worked so hard to minimize. I will, however, use a very light front end compression at a 3:1 ratio just to take the edge (two or three dB tops) of off the loudest parts of the track which then allows me to make the overall recording level hotter.
Back End EQ/Compression
Once you’ve recorded your acoustic, there are a few EQ and compression tricks I tend to use to help get the best sound possible. My EQ approach changes depending on whether the recording I’m making is a simple guitar/vocal or one where I’m planning to overdub additional instruments. For a guitar/vocal, I’ll be more sparing in my EQ. I tend to use 125hz as a place to pull a few dB if the recorded acoustic sound is slightly muddy or diffuse and 5000hz as the place to boost if I need a bit more brightness (see fig. 1). When it comes to integrating an acoustic into a fuller mix, especially one with drums and bass, I have a more dramatic approach that involves setting a high pass filter to effectively remove all frequencies below 120hz. This allows the proper sonic space for bass and kick drum while leaving the meat of the acoustic sound untouched. The approach to adding brightness is the same as above and can be added by boosting a few dB at 5000hz (see fig. 2). I tend not to compress the acoustic in the mix on guitar/vocals but when it comes to a band mix, it can really help the guitar to maintain its presence. I will generally compress at a 2.5:1 ratio with a fast attack/slower release approach (see fig. 3). Finally, given how easy it is to store settings, you might want to create acoustic guitar EQ and compression settings in your favorite plug-ins to speed up the process.
I happen to be a big fan of control room recording. It brings a great combination of casual and intimate to your session. So although it takes a bit more preparation and a little more care in the process, you can get great-sounding control room acoustic guitar parts without having to rely on anyone but yourself.
Cliff Goldmacher is a songwriter/engineer/producer/author and owner of recording studios in Nashville and Sonoma, California. Cliff’s articles have been published in EQ, Recording and ProSound News magazines and his eBook “The Songwriter’s Guide To Recording Professional Demos” is available as a free download from his site http://www.cliffgoldmacher.com/ebook.