Gauss Vents
The
vent dimensions as given by gauss are determined by the enclosure volume
The cabinet volumes in the table are given in cubic feet |
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1.2 | 1.3 | 1.5 | 2 | 2.5 | 3 | 4 | 5 |
6 | 8 | 10 | 12 | 14 | 16 | 20 | 24 |
These
vent options are for maximum output, disregarding distortion. The
numbers in the chart reference the speaker diameter and quantity, 1 or 2
X-MAX figures on the left are in thousandths of an inch |
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12" | 15" | 18" | 2x15" | 2x18" |
Power de-rating for maximum displacement limit
(That's a link also)
This de-rating curve baffled me for a while. What it means is that as the frequency is lowered, the maximum power the speaker can handle is lessened in order to stay within Xmax.
Consider a maximum excursion of 0.375" (10mm) for the 4583A. At 80hz, this will produce a sound pressure level of 117.6 dB at 1m, outdoors. Now, to maintain the same SPL at 40 hz, the diaphragm would have to move 40 mm. Needless to say, the cone leaves the basket.
Maintaining the same excursion, if the frequency is halved, the SPL drops by 12 dB. That de-rating curve shows the maximum power tyhe spweaker can handle as the frequency is lowered, staying within the limits of Xmax.
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