Yamaha YST-SW0110 Owner's Manual

Also see for YST-SW010: Owner's manual Service manual Manual

Contents

5EnglishAdvanced Yamaha Active Servo TechnologyThe theory behind Yamaha Active Servo Technol-ogy is based on two factors: the Helmholtz resona-tor and negative-impedance drive. Active ServoProcessing speakers reproduce the bass frequen-cies through an “air woofer,” which is a port oropening in the speaker’s cabinet.This opening is used instead of, and performs thefunctions of, a woofer in a conventionally designedspeaker system.Thus, signals of low amplitude within the cabinetcan, according to Helmholtz resonance theory, beoutput from this opening as waves of great ampli-tude if the size of the opening and the volume ofthe cabinet are in proportion to satisfy a certainratio. In order to accomplish this, moreover, theamplitudes within the cabinet must be both preciseand of sufficient power because these amplitudesmust overcome the “load” presented by the air inthe cabinet.This problem is resolved by a design in which theamplifier supplies special signals. If the electricalresistance of the voice coil could be reduced tozero, the movement of the speaker unit wouldbecome linear with respect to signal voltage. Toaccomplish this, the system utilizes a special nega-tive-impedance output-drive amplifier that sub-tracts the output impedance of the amplifier.By employing negative-impedance drive circuits,the amplifier is able to generate precise, low-ampli-tude, low frequency waves with superior dampingcharacteristics.These waves are then radiated from the cabinetopening as high-amplitude signals. The systemcan, therefore, by employing the negative-imped-ance output drive amplifier and a speaker cabinetfeaturing a Helmholtz resonator, reproduce anextremely wide range of frequencies with out-standing sound quality and low distortion.The features described above combine to create thefundamental structure of conventional YamahaActive Servo Technology.Our new Active Servo Technology — AdvancedYamaha Active Servo Technology — adoptsAdvanced Negative Impedance Converter (ANIC)circuits, which allow the conventional negativeimpedance converter to dynamically vary to selectan optimum value for speaker impedance variation.With these new ANIC circuits, Advanced YamahaActive Servo Technology provides a more stableperformance and improved sound pressure com-pared to conventional Yamaha Active Servo Tech-nology, resulting in more natural and dynamic bassreproduction.High-amplitudebass soundCabinetPortAir woofer(Helmholtz resonator)Advanced Negativeimpedance ConverterActive ServoProcessingAmplifierSignals of low amplitudeSignals