# Measuring PR/ported subwoofers outdoors



## fackamato (Sep 19, 2007)

As mentioned in this post: http://www.hometheatershack.com/for...-2x18-page-ranking-200l-new-3.html#post154701 , when measuring a subwoofer (like, outdoors, not in a room), do you not need to take into account everything that emits sound? That includes the driver itself, the PR(s)/the port. Otherwise you wouldn't get a realistic response, no?


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## brandonnash (Sep 11, 2006)

I think it depends on the configuration of the driver. I would imagine that a single measurement nearfield would be taken of the driver, a single taken of the port, a single taken of the combined, then an overlay of the two independent measurement (driver and port) that would use to compare the two(singles then combined). That's the way I would try it anyway.


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## ec114 (Jan 22, 2008)

brandonnash said:


> I think it depends on the configuration of the driver. I would imagine that a single measurement nearfield would be taken of the driver, a single taken of the port, a single taken of the combined, then an overlay of the two independent measurement (driver and port) that would use to compare the two(singles then combined). That's the way I would try it anyway.


I agree in principle, and ported full-range speakers are generally measured by (vector?) summing individual bass sources.

However, at, say, 20Hz, the wavelength is 56ft, meaning most practical direct radiators and resonators in "small" boxes are largely omnidirectional, humongous horns notwithstanding. Which--and totally guessing here--a 3ft baffle might yet have a couple dB worth of "shading" ability at those wavelengths. Not night and day, but still, if you're trying to measure what you've paid for...


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