During the 20th century a huge number of room acoustical parameters to describe concert hall acoustics were suggested. Too many, in the opinion of acousticians, who by the beginning of millennium arrived at some consensus expressed by the proposed set of five parameters now found in ISO 3382. One should expect that this quintet would prove to be able to explain and predict the subjective ranking of concert halls, e.g. Beranek‘s extensive rank-ordering of 58 concert halls. Indeed, Beranek has found high correlation between objective and subjective parameters, though not with the five aforementioned ISO-parameters. This author has (ICA 2010) pointed at some unsettling issues regarding former approaches, including the assumption of linearity and the uncritical use of hall average values representing the noticeably different listening conditions found throughout high-ranked halls (IOA Oslo 2008). Among the objectives addressed in this paper is a recent study based on Gade‘s 126 impulse responses measured in 11 European halls [4], Beranek‘s 58 hall rank ordering [3], a critical comment on linearity and orthogonal parameters, and a new method for testing parameter relevance, suggested by this author. A hundred years of reverberation time, but we still haven‘t found what we are listening for (sic). This paper is a status report on the struggle to find a set of acoustical parameters that explains and predicts the subjective ranking of concert halls.