Loudspeaker and Amplifier Specifications- De-mystified!

Sound system designers must routinely select and deploy power amplifiers for their projects. This can be a daunting task, as there are many things that must be known.


Which power rating do I use?


What SPL will it produce with my loudspeaker at various distances?


How much current will it draw from the utility company under various load conditions?


How much heat will it generate in the amplifier rack under various load conditions?


How can I figure this stuff out, starting with the typical (sometimes vague) sine wave power rating provided by the manufacturer?


How do I compare loudspeakers and amplifiers from different manufacturers, since they are often measured differently?


Which loudspeaker specifications are important, and what do they mean?


What is an appropriate frequency resolution for loudspeaker data and room acoustics modeling?

Frequently Asked Questions...


What is the CAF?

The CAF report is a specification sheet of carefully selected performance metrics. We developed it because we needed it, and have made it available for any amplifier manufacturer to use.


Is the CAF a Standard?

No, but it doesn't need to be. Many of the specs it contains are described by Standards. The CAF is all of the information you need to deploy a power amp, all in one place. If the industry ever decides a Standard is needed for this, the CAF should heavily influence it.


How are the tests run?

There are many ways to test amplifiers, which is why it is so difficult to compare various makes and models. The CAF measurement procedures are well-documented and available to anyone. They are the result of testing many amplifiers from multiple manufacturers. The CAF is concise, in that it only contains data needed by sound system designers to do their jobs.


Who does the testing?

Anyone with the necessary instrumentation and skill set. This is sometimes the manufacturer, but some manufacturers prefer to outsource it to a qualified test lab. The data is the property of the manufacturer and is distributed by the manufacturer.


What about loudspeaker data?

The CAF has a sibling - the Common Loudspeaker Format (CLF). The CLF was established in 2005 and is supported by over 70 manufacturers. The success of the CLF inspired the development of the CAF.


Why would a manufacturer use the CAF?

Simple. To assure that their products are properly deployed. Their tech support departments spend valuable time helping dealers figure out the answers to amplifier questions. A CAF report provides the answers. Errors are avoided. Credibility is established and preserved, which means more sales. Support for the CAF says "We're serious about amplifiers."