Loud and Low Subwoofer Ratings
Most people choose a powered subwoofer using the “Inches and Watts” method. They assume that a “big” driver and a relatively high amplifier power rating translate into better performance. The reality is that particular design tradeoffs involving not only driver size and amplifier power but also transducer motor strength, enclosure size, type (sealed vs. vented vs. passive radiator type) and tuning, among several other critical factors, dictate how well a powered subwoofer system will perform. Measurements as simple and as limited as driver size and amp power alone tell you absolutely nothing about how loud a subwoofer will play, how deep it goes, or whether its acoustic output will be relatively free of distortion.
As a means of addressing this problem borne of misinformation, the Consumer Electronics Association (CEA), has devised a standard method for determining the distortion-limited acoustic output capability of self-powered subwoofers. Results are stated in two easily understood numbers. The standard is formally called CEA 2010, but we call it Loud & Low because it tells you how loud and how low a subwoofer actually plays.
Under CEA2010, maximum Sound Pressure Level (SPL) measurements are made at six points using a special test tone. The lowest three -- 20, 25, 31.5Hz—constitute the “ultra low” range, while the upper three -- 40, 50 and 63Hz – taken together are the “low” bass range. The three readings for each range are arithmetically averaged to arrive at the Low and Ultra Low CEA2010 subwoofer performance ratings.
For example, CEA-2010 performance metrics for Polk Audio’s DSW microPRO4000 are expressed as follows:
Make & Model: Polk Audio DSW microPRO4000
Ultra Low (dB SPL) 110.2
Low (dB SPL) 119.7
As a means of making an intelligent purchasing decision that truly fits your needs, you can refer to CEA2010 metrics to reliably predict how different subwoofers compare in terms of how loud they play and how low they can clearly reproduce bass. For example, a small room devoted to high-end audio will benefit greatly from very deep bass reproduction (relatively balanced “ultra low” and “low” measurements) but less so from a woofer that plays especially loud. By contrast, a larger room intended for home theater and casual listening may require higher sound pressure levels through the “low” band while “ultra low” bass may be less important. Or you may wish to have it all. With CEA2010, affectionately known as “loud & low”, you can rely on one measurement to choose what suits your needs and fits your budget.
