I hope this makes sense.
If I had an 8" sub producing a 20Hz tone at 100 Db and I had an 18" sub making the same 100 Db at 20Hz, would one have more of a tactil impact than the other? In other words...is it all about the volume of the sub at a given frequency, or does the diameter of the cone have some effect on what you feel when watching a movie?
If so, can this be measured in WinISD?
Depends. How much you feel it is up to the amount of air moved by the cone and in order for an 8" to move as much as an 18", the excursion must be far greater and that means it needs to be very low mass. Acceleration/deceleration takes time and if it has lower mass/stronger motor assembly, it can respond faster. Also, the room size will make a difference and this is why a smaller woofer can sound better in a small room.
100dB, at what distance? It's not a fluke that you usually don't see 8" woofers in most home theaters and you'll never see them in a real movie theater. This doesn't mean you can't have good bass with 8" woofers, though. If the correct box is used for that particular driver, you can definitely have a good response but in order to really feel it, you need more piston area and that means either multiple 8" or one larger driver.
If you look at the toolbar at the top in WinISD, it has an SPL button. This shows the output in free field, based on the sensitivity and power handling. If you have a driver that puts out 89dB @ 1W, 1M and it handles 100W, you'll get about 109dB because 20dB is the difference between 1W and 100W, without any gain from hte box, speaker placement or from the room.
