High-Fidelity PWM-Based Amplifier Concept for Active Loudspeaker Systems with Very Low Energy Consumption

Nielsen K. High-Fidelity PWM-Based Amplifier Concept for Active Loudspeaker Systems with Very Low Energy Consumption. J Audio Eng Soc. 1997;45(7/8):554-570. Available from: https://aes.org/publications/elibrary-page/?id=7847

@article{Nielsen1997_7847,
  author = {Nielsen, Karsten},
  title = {{High-Fidelity PWM-Based Amplifier Concept for Active Loudspeaker Systems with Very Low Energy Consumption}},
  journal = {Journal of the Audio Engineering Society},
  volume = {45},
  number = {7/8},
  pages = {554--570},
  year = {1997},
  month = jul,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=7847}
}

TY  - JOUR
TI  - High-Fidelity PWM-Based Amplifier Concept for Active Loudspeaker Systems with Very Low Energy Consumption
AU  - Nielsen, Karsten
T2  - Journal of the Audio Engineering Society
J2  - J. Audio Eng. Soc.
VL  - 45
IS  - 7/8
SP  - 554
EP  - 570
PY  - 1997
DA  - 1997/07/06
UR  - https://aes.org/publications/elibrary-page/?id=7847
PB  - Audio Engineering Society
LA  - en
AB  - Various aspects of dedicated pulse-width-modulation (PWM)-based amplifiers for active loudspeaker systems are addressed. A new amplifier concept, dedicated to woofer and mid-range (0-4 kHz) loads, has been developed to provide a high-fidelity solution with minimum energy consumption in both analog and digital active loudspeaker systems. The concept is based on a novel feedback topology, a modulation strategy that is dependent on bandwidth, and the use of a switching frequency as low as 44.1 kHz without compromising the sound quality. Detailed measurements on two 200-W example implementations (700-Hz and 4-kHz bandwidths) are given, showing THD + N < 0.1 % and an unweighted dynamic around 110 dB. A new efficiency measure termed energy efficiency is defined, based on investigations of consumer behavior. The amplifier examples are shown to provide reductions in energy consumption of more than 90% compared to conventional principles, mainly because of a total idle power consumption of only 1.5 W, and power-stage efficiencies approaching 96% at higher output powers.
ER  -