Sound Design By Octaves
The sound system design process must use a practical frequency resolution. While some are pushing for more, many aren't using what they've got.
When all factors are considered, one octave is a practical resolution for the prediction of sound system performance, and is usually adequate — if the designer is devoting attention to the room acoustics as well as the direct field from the loudspeaker(s). The use of higher resolutions requires exorbitant amounts of time, and is plagued by inadequate acoustical data. A thorough one-octave evaluation of a system design for both direct and reflected sound should be able to indicate whether an acceptable level of performance has been achieved — which is the goal of the design process in the first place.
Ultimately, sound system designers must consider the frequency-dependence of the variables that determine a system's performance. A realistic frequency resolution must be used. A design that ignores frequency-dependence altogether will likely have very uneven coverage. If the resolution is too high, the design process becomes cumbersome and burdened by inaccurate data. One octave is a good compromise between “too little” and “too much.” In an age where “more is better” has become a mantra for progress and scientific advancement, as sound system designers, we should be sure that we're fully exploiting what we already have.
Pat Brown is president of Synergetic Audio Concepts (Syn-Aud-Con) Inc. and Electro-Acoustic Testing Company (ETC) Inc. Syn-Aud-Con conducts training seminars in audio and acoustics worldwide for those who operate, install, and design sound reinforcement systems. ETC Inc. performs precision loudspeaker testing for the audio industry. He can be reached at email@example.com.