All speakers will have some residual output that you might detect if you are standing next to them or put your ear next to the enclosure, but that "coloration" is not detectable at your listening area with program material--music or movie soundtracks.
As to bracing, the notion that "more bracing is better" has not been demonstrated in a number of tests that Axiom did last year on the audibility of distortion.http://www.axiomaudio.com/distortion.html
As you increase the amount of bracing in a speaker cabinet, you raise the resonant frequency, which may make the resonances more detectable, not less. Axiom's wedge-shaped anti-standing wave enclosure design suppresses the formation of resonances before they can become a problem.
The old "knock test" of a speaker enclosure says nothing about the potential detectability of any resonances. It's about as useful as kicking the tires on a car.
Here's a relevant excerpt from that article:
"For the designer, this presents an interesting paradox to beware of: Audible distortion may increase if distortion is lowered at the price of raising its occurrence frequency."
A good speaker design aims for no audible distortion and this means getting the proper amount of bracing not the most amount of bracing.
Axiom Resident Expert