The SILENT Brass features this unique Yamaha technology which uses the modeling of non-muted brass instruments to correct your instrument's tone when the Pickup Mute is in place. The resulting sound is so realistic, it's hard to tell whether or not the instrument is muted. Please note that Brass Resonance Modeling is only available when the STX-2 Personal Studio is combined with a PM1X/2X/3X/4X/5X/6X/7X Pickup Mute. It is not available with any other Personal Studio or Pickup Mute models. By co...