Why do some pianos have the bass bridge connected to the long bridge?

[Ron Nossaman]

> Why do some pianos have the bass bridge connected to the long bridge?
> I've heard this also called a "ring bridge".

With the tenor bridge ending out there in the big middle of the 
soundboard, the assembly isn't stiff enough. Connecting the low end 
of the bass bridge to it both stiffens the assembly, and mass loads 
the low tenor bridge with the bass bridge and strings. It helps the 
low impedance problems of the low tenor, but kills a fair amount of 
potential in the low bass - which can not move freely.

In smaller pianos, the low tenor bridge isn't so nearly parallel 
with the long side of the case, and the bridge end can usually be 
gotten closer to the rim for assembly stiffness. If not, no one 
seems to be too concerned about the low tenor of smaller pianos 
honking like a goose, where someone might conceivably notice it in 
bigger, presumably, higher performance pianos.

Ron N