Recording a good acoustic guitar sound, despite all the modern technology at our disposal, is still best achieved by recording a good quality guitar, well played, in an acoustically sympathetic environment, using a suitable microphone. There are other methods that can be used when using microphones isn’t appropriate, but we’ll come to those later.

Let’s assume you have your good guitar and your player is up to scratch — now we come to the acoustically sympathetic environment. The guitar, like most acoustic instruments, actually sounds best in a fairly live space as opposed to a highly deadened room. That doesn’t mean you have to record in a concert hall though — you might find that a room in your home with a tiled or vinyl floor works well. Lots of good guitar recordings have been made in kitchens and bathrooms.

If you don’t have a live space all is not lost, because you can liven up the sound by putting a sheet of hardboard or MDF on the floor in front of you to reflect some of the sound back up into the microphone. If you can arrange to have your back to a hard wall, that will help too, and you can always use artificial reverb to polish up the sound after you’ve done the recording.

Before moving on to the important subject of microphones, we need to consider the subject of unwanted noise. Acoustic guitars aren’t the loudest of instruments, especially if played finger style, so traffic noise is unwelcome, as indeed is the acoustic spill from open-backed headphones. If the player needs to use headphones when recording, then the fully enclosed type of headphone is recommended as very little sound leaks out. Other noises to be wary of are chair squeaks and unconscious foot-tapping. And as an example of other unpredictable sources, even the mere ticking of a watch might be audible during pauses!

The acoustic guitar produces a wide frequency range so you need a sensitive capacitor microphone to do it justice, especially at the high end. Furthermore, as capacitor microphones are far more sensitive than the more usual dynamic mics that you might use for live vocals and so on, you need less gain on your mixer or recorder to get a healthy recording level, which in turn means you get far less background noise.

At one time capacitor mics were very expensive but, now that Russian and Chinese companies are building them in large quantities, the price has tumbled to such an extent that you can now pick up a respectable capacitor mic for less than the cost of a decent stage dynamic mic. Even the big-name European mic manufacturers are producing attractively priced mics, and if you pick a good one it will last you for many years, so it’s a good investment that will never go out of fashion. Ideally you should use a cardioid pattern mic as these pick up sounds mainly from in front of them, which helps a little in rejecting unwanted sound from other directions. You can use either a large or a small diaphragm mic and still get good results, but be aware that all capacitor mics require phantom powering.

Having established that we need a cardioid capacitor microphone, there comes the question of where to put it. Instinct might suggest that you put it where the sound is loudest, and in the case of the acoustic guitar, that’s close to the sound hole. However, this almost always produces a boomy, boxy sound, so a better bet is to back off the mic to around 300mm and aim it at where the guitar neck joins the body. Even this doesn’t guarantee a great sound though, because every guitar is different and the acoustics of the environment also have an effect. One simple way to get a good sound quickly is to put on the headphones while the guitarist plays, then move the mic around while listening to the way the tone changes. As you move the mic more towards the neck, the tone gets thinner and brighter, while moving closer to the body creates a bigger, more bassy sound. Also, don’t be afraid to try very different mic positions — for example, you may find the best sound is with the mic ‘looking’ down on the guitar body from next to the player’s right ear. This works on the principle that if the sound reaching the player is good, the mic will pick up more or less the same sound in this position.

There’s a useful variation on this mic position when recording a player who also sings. The voice might easily be loud enough that you end up with a lot of vocals in the guitar mic. The solution is to position the vocal mic as normal, but to reverse the ‘by the right ear’ mic position so that the mic is looking up from beneath the guitar rather than looking down from above. This can produce substantially the same tone and give much better separation between the voice and guitar.

There’s a useful variation on this mic position when recording a player who also sings. The voice might easily be loud enough that you end up with a lot of vocals in the guitar mic. The solution is to position the vocal mic as normal, but to reverse the ‘by the right ear’ mic position so that the mic is looking up from beneath the guitar rather than looking down from above. This can produce substantially the same tone and give much better separation between the voice and guitar.

There are times when using a microphone isn’t a practical option, such as when recording in a noisy live environment, or when recording in a studio with other fairly loud musicians playing at the same time. Many modern acoustic guitars come with a bridge piezo-electric pickup system built in, often incorporating a three or four-band equaliser to help shape the sound to match more closely the natural sound of the instrument. Sometimes these can produce an acceptable sound, but all too often they are marred by a brittle top end, giving them a harsh, scratchy quality. There are more expensive and better-sounding pickup systems that combine different types of string pickup with miniature microphones inside the guitar body, but not everyone has access to one of these. Fortunately, there is another alternative.

In recent years physical modelling has become something of a buzzword with guitar players — digital technology is used to replicate the sound of classic amplifiers and speakers. This same technology can also be used to model the natural body resonances of acoustic instruments, such as acoustic guitars, and the BOSS AD-8 is a good example of this type of technology being applied in an easy-to-use, pedal format. Essentially, this little box takes the output from a conventional piezo bridge pickup and uses it to model the sound of six different classic guitar bodies. A further control adds the zing of the strings and, combined with the on-board EQ and reverb, you can get some very good sounds from it. If you try one you’ll probably find it doesn’t necessarily capture the sound of your own guitar in a totally faithful fashion, but it does sound like a ‘real’ guitar — and a pretty good one at that. A hint of the piezo sound still remains, but it is far less obtrusive than when using the direct output from the guitar and the results can be perfectly good enough for live performance or for recording ensembles of which the acoustic guitar is a part.

The AD-8 also includes reverb, which is important, because if you DI an instrument like the guitar, you lose the effect the room has on the sound. By adding a short reverb or ambience to the signal, the whole thing sounds more natural and convincing. You probably wouldn’t record a world-class soloist via a device like this, but then if you’re recording a solo guitar, there’s no reason not to use a microphone anyway. You’ll probably be pleasantly surprised at what can be achieved with this device and the choice of six different guitar-body characteristics gives you even more control. However, as always you should check out what the competition is doing in this area too, as sound is a very subjective thing to evaluate.

So recording the acoustic guitar needn’t be difficult. You can mic it using a fairly inexpensive capacitor mic, you can use a modelling acoustic guitar preamplifier such as the BOSS AD-8, or you can try to get by using the DI output from the guitar and then use EQ to tame its edginess and to make it sound as natural as possible. The last thing you need to do to get your guitar track sounding really professional is to add a little compression, though if your guitar track is part of a busy pop mix, rolling off some low end might make it sit better. Using a compression ratio of between 4:1 and 8:1, you can even up the sound and make it sound more dense but without losing its essential character. Aim for no more than 8dB of gain reduction on your signal peaks and use your ears when adjusting the threshold control so that you don’t overdo it. Most of the time a compressor attack time of 10 to 20ms and a release time of around 200ms will work fine but, again, do experiment because every model of compressor — hardware or software — has its own character.

And that’s pretty much it. If you follow these simple guidelines you should be able to produce a professional sounding guitar recording in next to no time, but if you’d like to learn more, check out the soundonsound.com website and use the search engine there to bring up all the past articles on this subject. You’ll also find detailed reviews of lots of BOSS and Roland products there too.