Cajon Comparsa Prototype

This post introduces the second prototype drum to be created for this project. This model is based on the Cajon Comparsa. The dimensions for the drum were taken from this website.

Although some lessons were learned from building the Cajon (such as not using a nail gun) and the new comparsa model is undoubtedly improved from the cajon, there were still some mistakes and plenty of tricky areas. Again my father helped me in the construction of this drum and he has years of experience with woodwork and a collection of the necessary tools and plenty that makes things easier (ie belt and orbital sanders, routers, jigsaws). This is making me think that perhaps if possible I would like to use one of the prototypes that we create to at least begin testing out the electronic and synthesis systems and possibly for inclusion in a final deliverable artifact. This is because if I were to attempt to build a drum on my own in order to gain credit for the design it would likely be time consuming, difficult and potentially expensive and it seems like perhaps, although clearly the ergonomics of the controller are important, for this project I need to focus more on other potentially more difficult areas. This is especially taking into account the legendary difficulty of the mapping stage. Mark Marshall for example said in his e-mail that in his DMI projects he has spent by far the most time fine tuning the mapping.

The comparsa is perhaps a little too tall to play on one's lap since for me, my arms are forced to bend upwards at the elbow from my waist to reach the tapa which is not particularly comfortable.

These issues suggest that perhaps a design closer in dimension to the Cajonito or even the Palito would be more suitable. I have some reservations about this though since I would like as much of the electronics to be housed internally as possible and obviously the smaller the controller is the less this is possible. Naturally however more internal electronics is going to mean more weight which could be a problem if the player is trying to hold the instrument with their legs.

Here are some pictures of the Comparsa:

As can be seen in the first few pictures the comparsa (according the demonstration videos presented on the Schlagwerk website) is typically held with opposing corners gripped between the knees and the tapa angled slightly downwards, with the sound hole facing away from the player. Also visible in the last few pictures are the marks from the wood filler used to fill up holes and chips created in the wood, evidence that putting the thing together is a little tricky.

Design details:

• 9mm thick MDF for sides and bottom
• Joined with wood glue and screws, screws have been counter-sunk
• 3.6mm plywood for tapa
• Joined with screws, counter-sunk
• 5mm sound hole
• All sides curved using router
• Coated with wood stain for an attractive finish

It was decided to use MDF for the body of the instrument since its cheaper than plywood. Also important to note that the quality of the wood is unimportant from a sound point of view since the sound will be synthesized, therefore cheap but sturdy wood can be used. Having said this the MDF presented as many problems with splitting as did the plywood. Also the MDF was thinner than the plywood at 9mm instead of 12mm. This size was chosen to make the instrument lighter, considering it was to be held between the legs.