That makes sense, although I wonder if not moving the resonances away from the corners by altering dimensions might be better in those cases, or at least achieve the same result.
Leob, Hkguy,
I am pretty certain that any free hanging panel will have "resonances" at the corners, no matter what the dimensions.
I put "resonances" in quotes because
technically resonances really don't occur at a particular place on a panel, but rather involve the whole panel. What I think you really mean is that for a free hanging panel, the corners will be antinodes (locations of maximum displacement) for certain resonant frequencies. In other words, the corners will tend to flap around wildly at certain frequencies. And that of course is true. In fact, for a free hanging panel, the corners will be antinodes for virtually every resonant frequency, not just a few.
Attached are typical mode shapes for a free hanging panel with square corners (first), for rounded corners (second).
In both, the corners will tend to flap, but with the rounded corners displacement amplitude (flapping) should be mitigated.
In most cases, I suspect the worst of the flapping comes from the fundamental, for which the mode shape typically looks like the third image. And often, this mode occurs at some low/inaudible frequency (i.e. below 20 Hz), so the flapping is all totally useless. So it makes sense for such panels to roll them off (i.e. use a high pass filter) to keep the lowest frequencies from reaching them, as Spedge often suggests.
Eric
