HOW TO RECORD A CAJON
THE SOUND OF THE CAJON
Before attempting to record any instrument it’s important to understand it's character. Which frequencies are most prominent? What range of frequencies do we want it to occupy in the mix? How loud is it? What is it's dynamic range? Also it is always worth bearing in mind that the most useful recording will always be the clearest, most natural and most honest one - effects can be added later! In the case of the cajon it is important to consider that we are dealing with an instrument with both a wide frequency range and a wide dynamic range, both of which need to be captured and represented if we are going to do the instrument justice. The bass tones of a cajon occupy (surprisingly enough!) the lower end of the frequency spectrum and the corners, especially in the case of a flamenco cajon (with snares), reach well into the highs. There are not many prominent mid-range frequencies that we would want to emphasise particularly - specific pitches or notes are not something we'd normally choose to bring out in a cajon part. The dynamics of the cajon are fundamental to it's overall sound and are a crucial element in any good recording or performance. It is the dynamics that give a cajon part it's energy, expression and feel.
Another important factor to consider is the space in which we record the cajon. Are there a lot of reflective surfaces? Is it a small or large space? What, if any, are the natural reverberations of the space like? In a larger “live” space with a lot of reverberation we must balance the sound of the cajon with the sound of the room. In a smaller, softer, “deader” environment we have greater flexibility regarding where we can place microphones in order to best capture the natural sound of the cajon.
With all these factors considered it is important that we capture the most important elements of the cajon's sound relative to the space. The bass frequencies are best recorded from the back of the cajon, close to the sound-hole. The attack and the higher frequencies of the snares are found more clearly at the front of the instrument. In almost all acoustic environments the bass frequencies are best captured at close range, somewhere between the hole itself and about a foot away. This is also where the cajon is at it's loudest, so a dynamic microphone built to handle low frequencies, such as a bass drum mic, is ideal for this job.
The front of the cajon can be miked in a variety of different ways depending on the acoustics of the space. In a smaller, deader-sounding room a microphone can be placed at a fair distance without the reverberations becoming an overwhelming factor in the recording. This is a good way of capturing dynamics, and a more sensitive microphone like a condenser will pick up the different volume levels, while representing the high frequencies not so prominent at the sound-hole. The front of the cajon also provides a much louder, sharper attack than the back, so allowing the higher-pitched sizzle of the snares to cut through is important. The attack can also be softened slightly by placing the mic at an angle. Somewhere between 90° and 45° from the front is usually a good bet, with 90° capturing the sharpest, loudest attack.
In a larger space a microphone placed any further than a metre away from the front will begin to act like an ambient mic and capture more of the room than the cajon. In this situation it's a good idea to get closer to the front of the instrument. Generally speaking the closer the mic is to the front of the cajon the more attack you will get. It will also give the impression of the cajon sounding more present and physically closer in the final mix which, traditionally at least, is not what you'd normally want from a percussion instrument. The further away the mic, the broader the dynamic range, so bringing the mic closer will give the effect of a sharper slap sound and slightly less variation in the dynamics. It is also worth remembering that when close-miking the front of a cajon a directional mic will only capture a small area of the instrument. In this case a large diaphragm condenser or an omni-directional or cardioid setting will help capture more of the front. Obviously it is important not to inhibit the percussionist, so keeping the mic lower and more central should ensure that it's not getting in their way. It is a good idea to experiment with miking up the front of the cajon with a few different mics in different positions and then balancing and choosing which ones to use.
For the purposes of this example we have kept it simple and used a small, relatively dead space and two microphones.
For the back we used an AKG D550 dynamic bass drum mic and pointed it directly at the sound-hole at a distance of about about 15cm. This recording will provide us with the depth of the bass and a softer, warmer interpretation of the snares.
In the front we placed an AKG C1000 condenser microphone about two feet (60cm) from the cajon at an angle of about 60°. This track will give us the attack and and brightness of the snare, a more focussed punch to the bass and more detailed dynamics.
The combination of both tracks is already sounding like an honest and workable recording:
Obviously different tracks can be balanced to taste – ultimately the desired sound of the cajon will also depend on it's context within the song and how it will find it's own space amongst the other instruments.
Once the recordings have been chosen and balanced it is time to EQ the sound of the instrument. Again, this will depend on the role of the cajon in the context of the song and how it fits in the mix. For the purposes of simply emphasising it's natural sound, it is again worth considering the character of the instrument. Firstly we would want to remove any overtones or prominent frequencies that create a specific pitch. These are generally found around the lower mid-range frequencies and can be pinpointed by sweeping a single band EQ until the pitch is very loud and resonant. In this case, the dominant sound was at 194Hz, so we applied a small, fairly narrow cut to give the bass less resonance and a more focussed punch. Other overtones were also reduced with a wide, shallow cut around 739Hz. This also allows more space in the mix for tuned instruments and voices which occupy mid-range frequencies. Finally a high shelf EQ was added to boost the top-end frequencies, adding to the hiss of the snares and generally giving the cajon a softer, livelier sound.
From this point on, any treatment added to the cajon sound would depend on context and personal preference. What we have here is an honest, natural representation of the cajon.