What is the effect of wall materials on a loudspeaker enclosure? Should they be rigid?
Acoustic suspension of speakers and ports in enclosures both rely on the “springiness” of the air. Technically, one normally talks of the compliance, roughly the inverse of the springiness. The compliance of the air is in parallel with that of the walls of the enclosure. This is because, when extra air goes in and the air is compressed, the walls are bulged out a little, so the air is less compressed than if the walls were completely rigid. Real walls are not infinitely rigid and compliant (deformable) walls slightly add to the compliance of the air or in other words make it a less stiff spring. There is a resonant frequency associated with this combined springiness. If we are talking about a port, then it is a Helmholtz resonance: the mass of air near the port is suspended on the ‘spring’ of the air & box. One can find this resonance by singing or playing a note nearby and listening, or putting a microphone inside. See our web page Helmholtz resonance. If you have a loudspeaker in a s
Acoustic suspension of speakers and ports in enclosures both rely on the “springiness” of the air. Technically, one normally talks of the compliance, inversely proportional to the spring stiffness. The compliance of the air is in parallel with that of the walls of the enclosure. This is because, when extra air goes in and the air is compressed, the walls are bulged out a little, so the air is less compressed than if the walls were completely rigid. Real walls are not infinitely rigid and compliant (deformable) walls slightly add to the compliance of the air or in other words make it a less stiff spring. There is a resonant frequency associated with this combined springiness. If we are talking about a port, then it is a Helmholtz resonance: the mass of air near the port is suspended on the ‘spring’ of the air & box. One can find this resonance by singing or playing a note nearby and listening, or putting a microphone inside. See our web page Helmholtz resonance. If you have a loudspeake
