Hi All, Im seeking some advice on building my own cabinet to match my 135Fender bassman. I plan on using an Eminence 300wat 8ohm speaker, and lm bassing the cab specs on a Fender 15" cab, so its the same width as my basshead & my fender 4X10 cab. The bin lm building is 660wx520hx440d. Can anyone give me the specs on the vent size, currently lm going for a 70mm high vent along the bottom of the bin, not a circular vent, but lm guessing the dims, I would realy appreciate some feedback from the Bass Brotherhood.