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I've asked around and Googled cajon recording techniques. I'm following the guidelines given by many but for some reason my cajon always comes out sounding like I'm slapping pieces of paper.

Currently my setup is an Audix D6 at a 45 degree angle to the edge of the rear hole and an Audix i5 catching the front of the attack a few inches away. I tried compressing and EQing it with no luck. We even moved into the bathroom to see if we could get a different sound.

Could this be a phase issue? Perhaps my room sucks? I think the cajon sounds great in the room but once I get it on equipment, that I know works well, it sounds terrible.

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  • This may be a phase issue. In theory you have to invert the phase of one mic, as they are facing each other. – Polosson Jan 24 '14 at 21:43
  • Even at a 90 degree angle to each other? Can you describe what a phase issue sounds like? I've never actually experienced it. – lampposteffect Jan 24 '14 at 21:48
  • These "phase issues" are more accurately time-based; both mics get the same or a similar sound wave, but one gets it before the other, so the waves are offset by a certain time, corresponding to a certain phase difference in the fundamental frequency of the sound (actually any frequency, but it's most apparent at the frequency with the greatest amplitude). This is regardless of the relative angle of the mics themselves. – KeithS Jan 24 '14 at 22:02
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    What phase issues sound like depend on what exactly you're recording and how far out of phase they are. Within 120 "degrees" of phase, frequencies combine constructively, and the combined sound is much the same as either one individually, just louder. Beyond 12 degrees, as the peak of one wave combines with the trough of the other, the frequencies will cancel and the level of sound at that frequency is reduced. Now, the instrument produces many different frequencies, not all of which will cancel between the two recorded waveforms. So you will hear something, but usually it's much "thinner". – KeithS Jan 24 '14 at 22:07
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To offer an actual answer to the question instead of a string of comments, I would start with just one or the other mic, get what you like out of it, then add the second. My choice is the D6 at the soundhole of the cajon, because that will give you the fundamental bass "thump" of the thing, as well as a decent amount of the snares, tambourine or other internal janglies that your particular instrument has suspended in it. Play with this mic's position and relative angle to the port. You don't want the disphragm of the mic at or too close to the actual level of the port, because the turbulence produced by the interaction of the air inside and outside the drum at this point will cause issues. A few inches outside the port and pointed directly at it will typically get you the best "boom"; a few inches inside will de-emphasize the bassy nature of the drum in favor of the impact and the internals.

Once you have the sound you like there, if it fits the mix, then forget the i5. However, if you want more of the "slap" of hand on wood than you get from behind the drum, then place your i5 pointed at this area of contact. Now the fun begins; you need to make sure the i5 isn't cancelling out anything you want from the D6, by very carefully moving the i5 to position it so that the fundamental frequency it's getting is "in-phase" with the D6's. The easiest way to do this is to give direction to a stage hand while you yourself PFL these two channels. As the assistant moves the mike directly toward or away from the box, you'll hear different frequencies get louder or softer. It doesn't take much.

Depending on the mic placement and the drum structure, you might be able to get enough access to measure and adjust the relative distances. Take a piece of string, and go inside the cajon, to the center of the front panel (the tapa) at about the height from the base at which the player normally strikes it (if he hits all over, find the geometric center). Hold the string against the tapa with one hand, while pulling it taut with the other, out to the microphone head. Mark the point at which the string touches the head, then keeping hold of both points on the string, move out in front of the cajon and stretch the string from the same point on the front of the tapa out toward the i5 (don't change your hold on the other end to adjust length). The string should just barely graze the i5's grille; have someone else move the mic in or out from the tapa until it's at the right distance and out of the way of the drummer's hands. Then, because the D6 is exactly the same distance behind the tapa as the i5 is in front of it, these two mics will be perfectly out of phase, so you'll need to invert polarity on one or the other so the signals combine correctly.

If this is a dedicated recording session, and you're not also playing for an audience, then you have control over the space and what else is in it. If you like the way the cajon sounds naturally in your space, then don't close-mic it, room-mic it; set up one or two small-diaphragm condensers at a distance from the instrument such that you get a good overall mix of the instrument itself and the surrounding room. These kinds of instruments get recorded in everything from vocal booths to bathrooms.

Mic placement is an art in itself. There's math, to be sure, just like there's math behind the perspective in a painting, but there are also so many variables that it's impractical to try to calculate the ideal microphone selection and placement. The best thing to do is experiment until you find something that works.

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    Excellent answer! Indeed even if you're not satisfied with the single-mic sound, it might be worthwhile to try some rather agressive post-processing instead of adding another mic. Cajón is quite a special case – you can do a lot with excitation, multiband expander, even hard distortion, that would sound crazy on other instruments but for Cajón just subtly increases the dynamic range and sound versatility, and introduces a bunch of extra parameters to tweak the sound with. But this only works well if you restrict yourself to one close mic; more will yield uncontrollable phase relations. – leftaroundabout Jan 25 '14 at 18:12
  • I've got some great sounding Cajon recordings with an MD-421 mic off at about 45 degrees to the front. And I concur - distortion and saturation is a must to get a full thick sound. – Adamski Apr 9 '15 at 20:24
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Do your mics sound good individually?

We actually experience phase issues everywhere. This is what gives a space it's sound and what changes the sound of an object or microphone when placed around in a space. However in the OPs case it's quite likely that the two mics are out of phase.

As a common example, this occurs each time you mic up a snare drum on the top and bottom. When you hit the snare, the top head goes in with the stick while the bottom head pushes out. This moves the air around the heads with them, thus the top mic will see a waveform that goes down then up and the bottom mic will see a waveform that does the opposite, up then down.

Zoom into your waveforms and see if this is what your are experiencing.

This is fixed simply by hitting the phase invert button on your track!

Once your mics are going in the same direction, usually you want them going up then down, you may also find there is a slight time offset as well. This occurs when one mic is closer to the impact than another. Simply drag the delayed waveform over until it lines up with the first one.

Now your drum should sound thick and full.

If you have a nice sounding room, I'd also reccomend to try placing the mic a couple of feet from the drum, rather than close miking it.

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  • This answer is good, but part of it assumes multitrack recording instead of a "live mixdown" such as through an audio console at the venue. While that may indeed be what the OP is doing, being able to correct phase/time problems by shifting the waveform a few milliseconds each way is something only relatively recently made available, so it's also worth it to know how to solve the problems on-site with proper mic positioning. – KeithS Jan 24 '14 at 23:51
  • Very true KeithS. Mic positioning is everything and should always be the first point of call. – Joseph Dutaillis Jan 25 '14 at 2:33
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Just one thing: a Recording is only as good as the room you record it!

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