 Also in the product line @-@ up were NS @-@ 10T , NS @-@ 10M X , NS @-@ 10MC , NS @-@ 10MT . The NS @-@ 10M X is a " Studio " with magnetic shielding and a different tweeter . In the 1990s Yamaha introduced the NS @-@ 10MT , a bass @-@ reflex version of the 10M X with a different tweeter and grille . Designed for home cinema , it has bass response down to 43 Hz , nominal impedance of 6 ohm and maximum power handling rated at 180 W. A miniature version named Natural Sound Surround Speaker NS10MM was launched in 1997 or 1998 . 
