I’ve been building cajons with “sound holes on the bottom” for 2 years and finally decided it was time to fit a few with a snare mechanism. I wanted to keep it simple and I wanted something that doesn’t require a hole in the side of the cajon box. On my cajons this is a super easy mechanism to take in and out. On a cajon with a normal sound hole it would take a bit of practice but would certainly be doable.
There are two common kinds of snares on cajons, those that use guitar strings, flamenco cajons, and those that use the same snare wires found on snare drums. There are many snare wire holder designs used in cajons with snare wires. Some have rigid stationary bars to hold the snare wires, some have rigid rotating bars or dowels that allow on-off and some cajons have rigid but removable bars.
This design is based on snare wires but it works because the wires are angled and held in place by a thin flexible bar that helps to press the wires onto the surface of the tapa. The design gives good snare, clear bass and is easy to remove. A disadvantage is it can not be removed while playing, you must reach into the cajon to add it or remove it.
Angled Snare Wire Orientation
The wires themselves have three important angles, one is the positioning of the wire mount on the bar to angle the wires towards the center of the cajon. The second is the cut off end of the wires, it progressively lengths such that all the wires end at the seat of the cajon, towards the center. I like to make the device then cut the wires so they just touch the seat. Because of these 2 angles the wires are not held tight by the seat. A direct hit over the wires results in a good snare but a hit to the side has much less snare. Contact with the seat causes a slight muting if the hit is high in the middle against the seat. I like this as I am constantly looking for different tones and this provides two distinct tones in close proximity.
The main advantage of the angled wires touching the top is that the snare sound is good in the upper center, but minimal to the side and minimal in the bass.
The third important angle keeps the snare wires pressed tightly against the tapa. It is achieved by both the inclination of the wires on the bar and the inclination of the bar on the bracket. I usually bend the wires where they attach to the metal bracket that holds them all together. The wires must be mounted such that the angle to the tapa is maximized. If you mount them on the other side such that they are flush with the tapa, the tension may in insufficient and the mechanism may fall out.
The flexible bar is a piece of thin 3mm tapa plywood cut narrow, about 19 mm and just long enough to fit between the sides. I am still experimenting with the best position but in my current favorite build the bottom of the bar is 11 cm below the bottom of the top. In some of these photos I’ve add three pieces to give the screws wood depth and change the flexibility, but I’ve also used two or even none. Even with a piece to thicken for wood depth, the screws poke through and should be ground flush.
After the mount is built if the wires are too long, cut them shorter. I use a 10 inch metal cutting wheel to cut snare wire, with the wires mounted in a jig it is much easier and cleaner than than with wire cutters. Snare wire is very tough. There are more photos on how to cut snare wire in the gallery at the end of the blog.
The bar is held in place by small notches in the mounting pieces and by the tension of the snare wire strings pressing against the tapa.
The bar mounting pieces are small. It’s nice to have a hand or mechanized scroll saw to shape them. I experimented with different lengths for the mounting brackets and found that a short piece with the notch is good but it is better to have a long backing piece. It makes it much easier to put the device in.
I’m currently using a bar to tapa angle somewhere around 30 to 40 degrees but I’m still experimenting. If the angle is too steep there will be little or no snare. If to shallow the device could fall out. The distance elevated from the tapa is very important. It must be close to the tapa, but not too close. Right now I am using about 15mm. This is a new design, please think of the measurements as preliminary. I don’t want to lock anyone into numbers that may not be optimal. If you make this design you are part of an experiment and please let us know what worked and didn’t in the comments.
I cut the slot for the bracket a little small. After the bracket pieces are glued in I round the contact edges/corners of the bar until the device slips into place.
The snare wires are held against the tapa by the combined pressure of the flexible bar, the inclination of the snare wires and the notch in the bracket. The pressure of the wires slightly bends the flexible bar. With each hit the bar flex and string rebound combine to produce a good snare sound.
If you want you can make two layers of mounting brackets. This will enable you to position the bar high or low. Which will change the amount of snare. The photo below shows the basic idea but it was the first and only time I have tried this so the shape of the pieces was not optimized. Next time I’ll make them progressively longer to help with getting the bar in. This will give you the option of a little snare or a lot. But you’ll get a lot of snare sound in the bass using the lower position. You could also have multiple flexible mounting bars, the one to fit the lower mounts could have longer snare wires, angled in or not.
There’s no on-off mechanism. Simply remove the snare bar to eliminate the snare sound. The only fine tuning is which level you place the snare.