In Part 1. I wrote about the material, the parameters and assembling of the cajon in general. Now let’s talk about that part of the cajon we use, or better to say, hit most often:
The playing surface (Tapa)
The playing surface (or frontplate) is the part of the instrument that the audience or customer first and foremost sees, so we often tend to pay too much attention to what it looks like and it can also distract our attention from other most important features of a good quality cajon. Of course it’s important to be aesthetic, but a trendy logo, a nice pattern or a cool finish is not all. The playing surface is the part of the cajon on which we will play, so that part of the instrument gives much of the sound quality.
The frontplate is made of plywood. The most commonly used wood in the order of frequency are birch and beech. Baltic birch plywood is the most popular and easiest available wood (in Hungary, Europe at least). It gives good vibration and also gives good bass and highs. Beech plywood is also relatively easy to obtain. It’s a bit harder than birch. There is also non-wood playing surface, eg. made of plastic or carbon fiber … not bad but I’d stick to wood (my personal opinion).
Here are the birch and beech wood next to each other:
The wood quality
A rule of thumb: high quality materials are likely to produce higher quality sound, poor quality materials adversely affect the sound of the cajon. I’ve already wrote about this in Part 1. It is especially important for the frontplate plywood that there is no lack of material in the intermediate layers (even partially). This can be checked by holding the plywood board towards strong light (lamp, sun) and where the light obviously illuminates the wood, there is a lack of intermediate material. Such material should not be installed as a playing surface.
Thickness and number of layers
The average playing surface thickness is between 2.5 mm and 3.5 mm. Playing surfaces that are thicker than 3.5 mm are too rigid and hard. It’s hard to play, and you can only play sounds with too much energy, which can be a burden for a longer concert. In addition, lighter hits (ghost notes, rolls) do not sound… Thinner playing surfaces are more sensitive and respond better to fine hits/strikes. For T.G. Cajons, I use a 2.7 – 3 mm thick frontplate that is resistant and sensitive enough.
A good playing surface is made of several layers of thinner plies to produce an overall “denser” material. Playing surfaces comprising fewer, thicker plies do not produce such crisp high tones, instead producing more mid-based tones. A minimum choice is high quality 3 mm thick plywood made of 3 plies, but the really good one is a 2.7 mm thick birch playing surface consisting of 5 layers.
Lows and highs
Always make sure that the high and low/bass tones are clearly distinguishable on the cajon, so they sound distinct of each other. Especially in the case of cheaper models, mid-range sounds may mask both highs and lows.
‘Click’ sound at the corners
The top two screws on either side can be slackened to leave a very small space between the body and the tapa to add extra click to the high tones. In some models, manufacturers usually cut off or sand from the upper corners of the body to leave a small gap between the body and the tapa. Well, this is a question of taste, whether there is a need for this extra ‘click’ sound … I think the cajon is fine without it, but this is my personal opinion 🙂
What do you think? What playing surface do you have? Post it on Facebook!