resonance freq. and -3 dB point (1 Viewer)

[Jeremy Illingworth]

I'm playing around in LspCAD and was wonderin exactly what resonance frequency and the -3 dB point are. With a 15 cm vent at 75 cm long I get 13.8 for resonance freq and 18.5 for the -3 dB poing. If I shorten the vent to 53 cm they change to 16 and 14. Which do I want? Lower resonance freq or lower -3 dB point?
jeremy

 

[Greg Monfort]

Resonant frequency is the frequency at which the box resonates, damping the driver and driving the vent to its max. F3 is the -3dB point (half power point) in the response curve. As to which is better depends on how they interact with the room, so use room function to help you make a decision if your room is ~ a box. FWIW, unless a room is small and/or highly resonant to LF I almost always tune to 16Hz.
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Loud is beautiful, if it's clean