I have an Ampeg SVT-410 cab (sealed). The cab has the exact same speakers as the 410HLF (ported) cab. I was wondering if it would be possible/bennificial to add ports to my cab. I'm thinking about mounting rear tube ports on the cab. Ampeg's 2x10 cab uses the same speakers and is rear ported the same way. Would it be okay to add identical ports to the top and bottom halfs of my cabinet, in order to lower the freequency responce? I don't know a lot about cabinet design and ports and tuning and all that, so any information will be helpful. Does anyone know the port dimentions on the SVT210HE? This cabinet is the same size as each half of my cab.