 The MTX Jackhammer, a 22-inch subwoofer made by MTX Audio, is capable of 2.5 inches of linear cone excursion, one way.That is a total range of 5 inches, which is potentially hazardous.The Thunder 1000000, the record holder for the largest subwoofer ever made, with a diameter of 60 inches, is capable of 6 inches of peak to peak cone excursion.