Hello everybody and welcome to this new tutorial! Today we're going to talk about how to record an acoustic guitar, an instrument that needs to be reproduced as natural sounding as possible to be good, and that is the reason why it cannot be digitally recreated via synth in a credible way.
First off let's say that there are two ways to record an acoustic guitar: using a microphone, or (if the guitar has a pickup), using the jack output of the guitar itself.
- Using the Microphone: first off you need a microphone suited to record acoustic instruments, such as the Shure Beta57, but there are many others very good and probably cheaper, for example made by Sennheiser. Condenser microphones may be even better, but they need an acoustically treated room in order to play at their best, so check the environment carefully before choosing.
Now we need to find the "sweet spot" of the guitar where to point the microphone, keeping in mind those rules: if you point the microphone toward the bottom of the guitar or behind it, the sound will result very deep and full of bass frequencies, same is if you point toward the sound hole: you will get a bassy sound that captures the internal resonance of the guitar.
The more you move toward the neck, the more you'll capture the strings sound, so the higher you will go in the neck, the more the sound will be brilliant.
Obviously you'll have to hear and decide for yourself, but I would consider a good spot the area near the 12th fret: this is where the neck joins the body and is usually regarded as the best place to record the acoustic guitar, since it is where we capture a full and even frequency response from the instrument; not too bassy and not too brilliant. If you need some extra string sound, you could also place another mic at the first fret to capture the nuances of the strings.
A typical miking setup for the acoustic guitar is with two Condenser microphones: one pointing the 12th fret, the other one pointing the bottom of the guitar, always on the front side as the other one: the one pointing to the bottom of the guitar will catch some low end that will later be mixed with the sound acquired with the other mike. At these two microphones can be added a third condenser one, set about one or two mt. away from the player in order to catch some of the room Reverb.
- Using the pickup: Many acoustic guitars nowadays, even the cheaper ones, have built-in a piezo pickup, and a battery-powered preamp, sometimes even with an equalization section too!
To record the sample in the video for this article, I have used an Ibanez V72 Cent, a cheap acoustic guitar with a built-in preamp, a volume, bass and treble control, and a built-in tuner too.
So first off I have found a good compromise in the built-in equalization, slightly cutting the treble and boosting the lows to give it a more "round" tone, then I went with the jack straight to the input of my audio interface.
- Once you have the signal on your D.A.W., is time to process it. You can use any plugin you want, usually any D.A.W. has some processing plugin bundled, but if you need some, I suggest you the Reaplug Suite, which is freeware and it sounds great.
First off I'd suggest to Equalize, but be very gentle: we need to preserve the naturality and the tonal richness of the acoustic instrument, so there's no need to overprocess the signal: we may just use a high pass filter to take away the lows we don't need, such as the frequencies below 50hz (sometimes, if we're on a more dense mix, it's best to take out everything below 100hz, or even 2/300hz, if we want just the guitar strum to pop out of the mix), and gently subtract a little (-3db) in the areas around 100-300 hz and 1-3 khz, if the sound is a little boomy or needs to be more open and transparent. Boosting between 5khz and 10khz will add sparkle, cutting between 1khz and 3khz will reduce harshness.
For the solo parts, we can instead boost some decibel (e.g. 3), to the 5-7khz area, in order to add some presence.
Now it's time for Compression, which can be normal or multiband. For the normal compression, just set a ratio between 4:1 and 12:1, according to the dynamic range of the song (the more volume differencies between quiet and loud picking, the higher the ratio should be), short attack (around 20ms) and medium release times (around 0,5sec), and a threshold set to around -15db.
The Multiband Compression, instead, gives you the opportunity to choose the amount of compression to apply to the single frequency areas, which can be adjusted through the controls.
This may be useful, since it can be used as a halfway between a compressor and an equalizer, and can help to reduce volume and presence of single areas of your signal (for example the lows between 100 and 300hz) and boost others (between 5 and 7 khz), without changing the overall tone.
Once you are satisfied with your tone, you can add (if needed, especially if you have recorded directly from the jack output) a Harmonic Exciter to add some sparkle to the tone, or a Reverb, like Freeverb, set very low, just to give to your sound that little resonance that it needs to be realistic; we can use for example a Plate reverb to add vitality, with a decay time of between 2 and 3 seconds.
So the Chain is: Guitar->Equalization->Compression->Harmonic Exciter (if needed)->Reverb (If Needed)