Quote Originally Posted by N Boros View Post
Tai,

I'm a little confused by why you prefer a down-firing subwoofer. From what I understand any bass coming out of just about any subwoofer should be omnidirectional, which means that it shouldn't sound different if it is down-firing or not (unless you are crossing it over very high). I think that the orientation of the woofer is more of a design choice related possibly most to aesthetics than performance.
Downfiring woofers have gravity acting on their forward/back motion. This is just another force that creates inaccuracies in the final signal. In front firing woofers, gravity is acting perpendicular to the woofer motion and does not effect woofer travel differently across the woofer's motion. In downfiring systems, it does. The pressure inside the box works against the cone as mentioned previously by Rythmik and Dave, but now you're adding complementary force to the woofer as it pushes forward, and impeding the motion as it draws back. This means you have to correct for more forces through servo or EQ.

Since we're on the topic, I'm not sure if a downfiring sub gives an advantage by using the floor as a re-radiating area, or by using the short distance between the cone and the floor as a way to increase air velocity of the wave as it leaves the woofer? This is what some speakers do that are vented on the under-side of the speaker, such as Zu's speakers. It makes sense to me, but I'm not sure how the physics of it actually end up in the real world.