I was reading a Music Magazine, which had an article by a PA Techo, who talked about that having vent ports in small cabs in not always a good thing. It was mainly to do with cabs with say, 2 x 10" speakers. He indicated that by not porting for small speakers, the sealed cushioning effect of the air inside, stops over extension of the speaker cone/driver. Therefore, you can drive the speakers harder, than ported speakers. However, doesn't this restriction and responding time of the cones physical moment, effect the quality of sound, especially the low frequencies etc?? Does anyone know what cabs manufactures use this non-ported design ??