Hi guys, Well, a lot great info, a few minor inaccuracy's... Even the Richard Hardesty post is more opinion and not cast in stone.
Yes, A passive radiator is more of a vented or ported design. When we do a ported speaker, Lengthening the port lowers the frequency of air moving through the port so changes the frequency the woofer peaks at. Where Richard was not quite accurate in his description is that it is completely feasible to port/vent a driver to be very smooth and accurate bass, it is then a function of a well damped amplifier to control it. There are many ported speakers out there that are great. A passive radiator works similarly in that as you add mass to the radiator, it will like a port, change frequency where there is a peak or dip and by how much. Every driver does change spec as it is used over the years and fact is, a sealed box comes much closer in keeping its original sound as it wears and a ported box is the same. Oddly enough in my own speakers at home right now, I have 3 pair built. A 10 inch 3 way in a sealed box, an 7 inch mtm in a ported box and a 12 inch 2 way (big Heil amt) in a passive radiator box. All 3 are flat, accurate and fast with the right equipment in front of them.
Yes, A passive radiator is more of a vented or ported design. When we do a ported speaker, Lengthening the port lowers the frequency of air moving through the port so changes the frequency the woofer peaks at. Where Richard was not quite accurate in his description is that it is completely feasible to port/vent a driver to be very smooth and accurate bass, it is then a function of a well damped amplifier to control it. There are many ported speakers out there that are great. A passive radiator works similarly in that as you add mass to the radiator, it will like a port, change frequency where there is a peak or dip and by how much. Every driver does change spec as it is used over the years and fact is, a sealed box comes much closer in keeping its original sound as it wears and a ported box is the same. Oddly enough in my own speakers at home right now, I have 3 pair built. A 10 inch 3 way in a sealed box, an 7 inch mtm in a ported box and a 12 inch 2 way (big Heil amt) in a passive radiator box. All 3 are flat, accurate and fast with the right equipment in front of them.