MartinLogan SWT-1 Subwoofer Wireless Transmitter for Dynamo 700 and Dynamo 1000 (Single, Black) (Discontinued by Manufacturer) Although correct placement plays a key role in optimizing subwoofer performance, sometimes it imposes the inconvenience (not to mention unsightliness!) of running long lengths of cable through walls The Dynamo 700 incorporates a wireless receiver (digital RF transmission) for use with the optional SWT-1 MartinLogan Subwoofer Wireless Transmitter (sold separately, see dealer) in which case, cable clutter also becomes a moot point! Maximum range of 30-40 feet. One SWT-1 transmitter is required per subwoofer.