A few years ago at A7hz, we tested several clapboard designs for simple reverberation measurements: here are our findings!
A clapper is made of two pieces of wood with flat surfaces and hinges, emitting a loud and short noise when closed. For acoustics enthusiasts, this is a good way to perform basic Reverberation Time measurements. Especially coupled with the free ClapReverb app we released on iOS! By the way, the latest version 2.2.3 of ClapReverb is now available.
ClapReverb app for iOS :
The choice of MDF (Medium Density Fiberboard)
We started with the assumption that a clap would work better if it was made of a noble wood like oak. In practice, this type of wood is not optimal because of its permanent evolution. Many elements such as the cutting method, the humidity outside, or the temperature, affect its shape and appearance. In fact, because hardwood is not perfectly flat, the contact between the two surfaces in a clapper is not optimal.
MDF wood is made from wood fibers glued together and compressed. It has the advantage of being dense and heavy enough for our clapboard. Moreover, with its composition, it is not affected by temperature or humidity and the two parts remain perfectly flat.
The installation of the hinges is important to allow a good system of hooking between the two plates. When the clapper closes, the two parts will touch at exactly the same time and produce a good clap.
To improve performance in Low Frequencies
Finally, we wanted to optimize the frequency range of the clapper, i.e., it should emit frequencies as low as possible. The use of a kind of chipboard, in particular MDF, is the best solution in this case.
To go further, the second parameter to take into account to improve the quality of the clap is its size. The bigger it is, the more it will emit in the low frequencies.
The ClapReverb app for iOS
In connection with the manufacture of a clap, our acoustic engineers have also developed an application called ClapReverb. This application, available for free download, allows you to measure the reverberation time of the room you are in.
Easy to use and intuitive, this tool is the perfect example of A7hz’ will to innovate in the field of acoustics !