The bass and treble rolloff is related to the output transformers, and are not specific to the triodes. My Berning SET ZOTL has no bass or treble problems,it's pure "midrange magic" from top to bottom. It has no output transformers. However, my speakers roll off at about 40Hz, so there is a lack of real deep bass in my system. But, it is surprising how I never miss any of the stuff under 40Hz, and quite often there is nothing on the recording that goes that deep anyway.
Also, for maximum coherency with SET amplifiers, single-driver louspeaker systems are preferred, due to the elimination of the crossovers and the true single point-source of sound for each channel.
Also, for maximum coherency with SET amplifiers, single-driver louspeaker systems are preferred, due to the elimination of the crossovers and the true single point-source of sound for each channel.