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Author
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Topic: Full space, Half space and Very Low Frequencies
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Ray Derrick
Master Film Handler
Posts: 310
From: Sydney, Australia
Registered: Sep 2001
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posted 01-29-2003 04:47 AM
Nice explanation, Rob.
Antonio, I think you will find these numbers apply to a perfect world where the reflective surfaces are 100% efficient and do not absorb any energy. At the frequencies involved, this doesn't happen very often in the real world.
Full space is when a speaker is suspended in free space, well away from any floor, walls or ceiling. It is usually measured in an anechoic chamber where there are no reflections. It is rare for a bass speaker to be mounted this way. Half space can be thought of as a speaker mounted in the middle of a very large wall, or sitting in the middle of a large floor area. To get the full 6dB increase, the wall or floor should reflect ALL of the sound energy and the relected sound must add perfectly with the direct sound (as there are time delays involved there will be slight phase differences so it will be close, but not perfect). So in reality you could expect these numbers to be a little less.
Quarter space would theoretically yield a further increase of 6dB over half space, and eighth space (at the junction of two walls and a floor) - another 6dB. But in practice? I don't think so! [ 01-29-2003, 09:27 AM: Message edited by: Ray Derrick ]
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