Loudspeaker and Amplifier Power Ratings: Is it Time to Start Over?

Presenters:
Klas Dalbjörn, Powersoft S.P.A. - Scandicci, Italy
Charles Hughes, Excelsior Audio - Gastonia, NC, USA; AFMG - Berlin, Germany
Claudio Lastrucci, Powersoft S.p.a. - Scandicci (FI), Italy

What are the relevant requirements and how can we move forward to a unified way to understand and specify loudspeakers and amplifiers? A system designer will want to have specifications for loudspeakers and amplifiers (or for powered loudspeakers) that answer the questions: • How loud can I play with a given solution with the program material? • How much mains current will it draw and what heat dissipation will I have with my desired SPL? The currently used methods for specifying loudspeakers and amplifiers leave room for improvement when it comes to simplifying this. From the loudspeaker side we will discuss the "power" consumed by a loudspeaker and what determines this. We will present a newer method, based on the output response of a loudspeaker, to quantify the maximum input level. Also discussed will be peak input level capability of the loudspeaker. From the amplifier side we will look what the real world demand is for an amplifier. How do some design concepts compare when it comes to the compromises made to keep the costs down? We will look at some existing amplifier measurement methods; how do they relate to the actual demand and the achievable SPL when aligned with the existing loudspeaker measurements standards? Examples will be shown regarding flaws in only looking at voltage. Loudspeakers vary in how reactive they are and many modern amplifiers have the ability to only consume the real power needed (i.e., not turn the apparent power into heat losses). This suggests that a future proof amplifier and loudspeaker method considers real power usage. An attempt to propose a way forward will be presented, which will likely lead to an interesting discussion in the last part of this session.