In order to provide an audible indication of the time, the Master Grande Tradition Grande Complication with a mechanism striking the hours, quarters and minutes on demand. The acoustic quality of a striking watch relies heavily on the gongs which are the essential sound producing elements. To deliver the best possible sound, Jaeger-LeCoultre has developed a completely new cathedral gong, creating an extremely rich sound. These gongs are made of a special alloy and manufactured completely in one piece; their cross section being square and not round in order to provide a larger contact point for the hammer which in turn can strike more forcefully. Usually the sound of a repeater gong is enhanced by the vibration of the case of the watch. However, the manufacture’s experts installed a different kind of ‘loudspeaker’, using their patented ‘crystal gong’, in which the heels of the gongs are attached to a layer of metallic foil coated onto the watch’s sapphire crystal. When the user pushes the repeater slide on the side of the platinum watchcase, two small hammers can be seen striking when viewed through the case-back. Watchmakers have invented a special mechanism christened the ‘trébuchet hammer’ to further enhance the sound of the actual striking. Instead of a traditional hammer they devised a dual-axis-system with a special joint on a moveable arm. Upon activation, the hammers are accelerated until they touch a small finger, whereupon a second moveable arm is released, thus helping to accelerate the hammers further shortly before the impact. This method utilizes around 80 percent of the force applied by the spring, whilst traditional hammer systems only deliver a mere 10 to 30 percent of the power originally applied.