How Good Is Your Port

Ported enclosures are known to extend the low-frequency output of loudspeakers by exploiting the Helmholtz resonator effect produced by the compliance of the air inside the enclosure and inertance of the air in the port. This article looks at the problem of port nonlinearity to determine the correct port size, and the acoustic impedance of the port under high air velocity. This article was originally published in audioXpress, September 2001.

This article examines the problem of subwoofer placement in odd-shaped rooms, exploring corner locations of subwoofers and some pros and cons of single-woofer versus dual-woofer systems for a given placement within a listening room. In the article, the author extends the analysis and actually generates the “room contribution” curves for a non-rectangular room. This article was originally published in audioXpress, September 2002.

With the availability of low-cost, PC-based acoustic data acquisition systems, experienced hobbyists can make highly accurate loudspeaker frequency-response measurements without an anechoic chamber. The power of these systems comes at a price. These systems window the time-domain measurement to eliminate room reflections. This, in turn, limits low-frequency response. This article was originally published in audioXpress, June 2012.