Rex---I think the 811 is very similar in sound to the 511, of course you have to cross it over higher. I've heard some most excellent systems using the 811 horn, Altec Valencias and Model 19s. I used 811s myself for awhile and liked them. Great horn if you want something compact and will crossover at 800hz or higher. Like the 511 the 811 benefits by damping the horn, non-hardening modeling clay in the "lips" and screwing the horn securely to a baffle will do the trick.