Wayne Parham Messages: 18748 Registered: January 2001
Illuminati (33rd Degree)
I never apply any damping material to the horns. The bell mode frequency is well below the passband and it is highly damped by the horn's mass, so I don't see any need to damp it further. The plastic is really thick.
That said, it doesn't hurt anything. Lots of our friends here do it, probably as a perfectionist move. I don't see any difference in measurements, but if it makes 'em feel better, there's certainly no harm in doing it.