Pontoon bridge Earl of Shrewsbury crossed the Oise river across a pontoon bridge of portable leather vessels in 1441. Ottoman engineers built a pontoon bridge across the Golden Horn during the Siege of Constantinople (1453), using over a thousand barrels. The bridge was strong enough to support carts. The Ottoman Army constructed a pontoon bridge during the Siege of Rhodes (1480). Venetian pioneers built a floating bridge across the Adige at the Battle of Calliano (1487). The Spanish Army constructed a pontoon bridge at the Battle of Garigliano (1503). The Spanish Army of Flanders under Alexander Farnese, Duke of Parma built an
Acoustic suspension acoustic suspension, with a separate, sealed air-space, even if the woofer itself is not. One notable exception to this was the Sonus Faber Stradivari Homage which uses a ported enclosure for the midrange. The two most common types of speaker enclosure are acoustic suspension (sometimes called pneumatic suspension) and bass reflex, so they are worth comparing. In both cases, the tuning affects the lower end of the driver's response but above a certain frequency, the driver itself becomes the dominant factor and the size of the enclosure and ports (if any) become irrelevant. In general, acoustic suspension systems (driver +