DB/SB dinner jacket/lounge suit formality question

[Sander]

"Why are DB dinner jackets less formal than SB ones while with lounge suits it's the other way round?"

just didn't fit in the title line.

I guess it has something to do with tradition, but I'd be happy if someone could shed some light on this matter.

 

[Sanguis Mortuum]

It isn't the other way around with lounge suits, neither is really any more formal than the other. A DB just give gives an impression of formality for various reasons, such as the association with the military and the simple fact that they're much less common.

It is less formal with regard to dinner jackets because SB ones came first as an evolution from the dress coat.

 

[F. Corbera]

DB lounge suits are not "more formal" than SB. Lounge suits, when they appeared, were generally worn with vests. A vested DB or SB suit, in this historical context, could be viewed as more "formal" than suits of either mode without vests.

The vest was the first to go generally on DB suits, making them lest "formal" than SB suits that persisted longer in general wear with vests.

An SB dinner suit with peaked lapels worn with a full evening dress vest and wing collar can be viewed as more "formal" than a DB simply because the former's configuration is the closest to white tie, the form of evening dress for which tuxedos and dress lounges are the informalizing adaptation. if you lose the white tie kit from that SB dinner suit, however, it's very pedantic to claim that there is any real difference between that in a turndown collar and a DB.

Why do you ask?

 

[Sander]

^ just curious.

I certainly recall a few sources that state that DBs are a little more formal than SBs. Will on ASW for example recommends a navy DB for a wedding because it's as formal as a 'normal' suit gets.