Wayne Parham Messages: 18789 Registered: January 2001
Illuminati (33rd Degree)
It's not just attenuation, it's ripple. It may be barely audible or perhaps even inaudible in the best cases, but the fact remains that the abrupt change of impedance created by a semi-transparent barrier causes reflections, and in turn, ripple. The foam spreads it out more, and may be desirable. But I kind of like the look of cloth grilles, so I use them sometimes in spite of their negative effects.