The live version may not have that exact frequency. Or the acoustics of the hall and the audio system may have acted as a filter at that frequency. But it migh

The live version may not have that exact frequency. Or the acoustics of the hall and the audio system may have acted as a filter at that frequency. But it might be more likely that the hard disks just weren't vulnerable, yeah. (5400rpm in '89, was that common?) Otherwise, if they did play the original song, then the loudness could have made the effect even worse.