In Reply to: PiAlign port posted by Adrian Mack on September 13, 2003 at 18:20:14:
A Helmholtz resonator and a waveguide are two different things. You will have waveguide behaviour in a port if it is presented with energies where standing waves develop. But that is a separate issue from the Helmholtz frequency. Most speakers are tuned below 100Hz using ports with dimensions that wouldn't act as waveguides until midrange frequecies. That's why there is acoustic insulation inside - to limit midrange energies and prevent the duct from acting as a waveguide.
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