The buzz was described as occurring when trying to get some lows. Any amount of turning up is liable to cause driver conniptions when one is pushing while the other pulls in the same cabinet. The tuning is shot to hell with overexcursion happening at a fraction of the nominal power handling.
Instead of the power being applied to making lows it goes instead to making its cab mate fly in the opposite direction, and vice versa, while the combined audio output in front sums to zero.