How Is Bass Divided Among Speakers If No Sub?

Another Dolby link.[http://www.dolby.com/uploadedFiles/Assets/US/Doc/Professional/42_DDFAQ.pdf]

As mentioned it will depend on the processor you have. But when you set your processor up and select large fronts and small rears I would say most of it goes to the fronts.

Yes, your processor controls bass distribution. If you have all your speakers set to large, all get full range sound. If you have any of the centre or rears set to small, their low frequencies are sent to the mains. If you do not have bass processing on your amp/receiver, then all speakers work full range.

If a 5.1 system has identical speakers all around with 15 inch woofers and all of the speakers are set to "large" on the processor, does the serious bass get evenly distributed to all speakers? Say, like an explosion or a dinosaur stomping?

My internet is giving problems, so if I don't post, that's the reason. With Dolby Digital, I would think that if you have the processor set to large for all five, only that one channel should get that bass, if they mixed it this way. More channels will, if they mixed it to do that. IOW, if an explosion goes off in the left rear, it should give all the bass if, it was mixed/made to do so, is my understanding. The channels are supposed to be totally isolated from each other. With the sub on, it will probably get bass from that one channel explosion, if they intended it to do so, during the making/mixing of the movie. Dolby Pro-Logic could not do a lot of this, like true separate channels, and it had limited frequency response to the mono rears.

Obviously, only the channel(s) getting the bass will produce it if all speakers are set to large. Although bass is generally non-directional, so regardless of which speaker it comes from it will likely sound as if it's coming from everywhere.

The downside to setting all speakers to large is that bass frequencies really suck a lot of amp power, so typically the mid-band will suffer. That's why most people use a sub, it lessens the load on the amp. I expect also that most low bass sound effects are mixed to the main speakers anyway, so running centre and rears on large doesn't make a lot of sense. Very few centre/rear speakers can handle deep bass.