Cabinet thickness, when little to no bracing is used, is extremely important. Many (lower cost, sometimes higher cost) speakers available today use little if any bracing at all. Using a 3/4" or thicker material such as MDF would be paramount. The speaker enclosure will still be quite resonant however.
A thinner material can be used if it is rigid enough and heavily braced internally.
Building a true resonance free cabinet is not only complicated but expensive. It also can require exotic materials in some cases. Normal, regularly available materials can be used, however, the process tends to become more complicated.