The ohm room size guide is confusing...I'm guessing that you could fill a very large room with a seating position 12' back using the OhmWalsh 2000...but only from 60 hz or so on up as the big room would suck out the lower bass....if that is correct, then their website is actually suggesting you need larger more expensive models in order to get the bass performance without a sub???
In my case, I'm using a Power Sound Audio S1500 which is pretty fast and has great tonality.