What is port freq (Fb) and cut-off freq (F3) mean for a subwoofer box?

Fb is the physical tuning of the port with the woofer loaded into it. F3 is how low it can safely play without the possibility of the woofer unloading and blowing.

With SUBS you will desire to contemplate that your sub container can exchange the WATTAGE mandatory to run your speaker as a sealed container with a sub 100w = 100w however the 100w sub in a ported container would wish 200w looking on port length and container Litres A PORTED container ability extra AIR DISPLACEMENT so which you like extra power to pass THE AIR A SEALED container keeps THE RMS OF THE WOOFER AND the flexibility FROM THE AMP does not exchange IF A SUB IS 4 hundred W RMS @ 4 Ohm and you RUN 2 this would be 800 W RMS you will desire :- 4 hundred W RMS via 2 CHANNEL for each @ 4 Ohm sealed 800 W RMS via a million CHANNEL MONO BLOCK @ 4 Ohm sealed 1000 W RMS via a million CHANNEL MONO BLOCK @ 2 Ohm sealed + 25 % extra power if ported it is often extra desirable to over power than below power you could turn your income down yet you cant get extra power from an amp purchase turning up the income on an amp that has no longer adequate power. Sealed = precise bass ported = exaggerated bass bandpass = exaggerated bass with a slender band of frequencies (it fairly is truthfully a sealed and a ported in a single, additionally utilized in opposition). The uncommon ones (extra for opposition use): T-line (Transmission Line) Solobaric Folded Horn Conical container Is what produces deep base 2 8" subs here in Aus produced a hundred and forty db in a specially equipped container so length is done determination in basic terms a container could additionally exchange the Wattage of a speaker looking on sort and length of the container and your amp would desire to tournament the RMS which you finally end up with there r equations you will locate on the internet

well thats just the measurements needed to make the sub sound its best. sorry i dont really know how to explain this.