Re: question about non ported speakers
A port isn't used to allow a cabinet/speaker to "breathe" (except in one case I'll mention afterwards). The purpose of a port is to act as a Helmholtz resonator; in simple terms, the low frequencies of the speaker are produced by the movement of air through the port, rather than from the driver pushing air back and forth (although it is the driver movement that is causing the air in the port to move).
Sealed speakers do not have a port. Generally speaking, sealed speakers will not play as low because the low frequencies that would be produced by the port are not being produced anymore. The argument for tightening up the bass comes from the fact there can be either a delay in sound being produced by a port versus a driver or at high volumes distortion from the small port. But that is not a universal truth. Rear ported speakers can also sound boomy if they are placed close to the wall.
I have seen one or two speakers that have been designed with a tiny hole, not to act as a port, but to let air in and out. Usually, a sealed speaker is supposed to be sealed and you don't want any air to leak in or out. The compression of the air actually has an effect on the driver, of course. However, in these speakers, I guess they did not want that to be a factor for whatever reason.