New materials have been developed to make the RF-X lighter than its predecessors but also to maintain its durability – helping to position the RF-X as a versatile product suited for any challenging working environment. It features a four-layer acoustic filter design comprised of the outer vented composite panel, a wool fabric layer, an air gap layer and an inner acoustic foam layer.
This multi-layer design differentiates the RF-X from its competitors by filtering frequencies evenly across the whole spectrum, helping to ensuring that recordings exhibit almost zero sound coloration when using the filter.
Even if it's a cardioid mic and is listening mostly to just you, it's still picking up reflections from your voice or instrument that are bouncing off the walls and coming back to the mic. The goal of acoustic treatment is to minimize the pickup of such reflections so your primary sound source comes through as pure as possible.
Some materials are good at absorbing or reflecting particular frequencies - for example, foam absorbs highs really well, but does nothing for lows.