Alvar Aalto took part in the invitational competition in 1959 with the entry number '17991'. He won the competition and went on to rework the plan at the city building committee's behest from 1961 right up to his death.
From 1970 to 1976 his German collaborator was Bauasessor Horst Loy; the opera house was finally built between 1981 and 1988 under the supervision of the German architect Harald Deilmann, mainly on the basis of drawings left by Aalto.
The basic plan remained unaltered throughout the design and construction process. The opera house contains a large, asymmetrical auditorium with seating for a total of some 1,100 spectators, partly on the sloping parquet and partly on three rows of balconies with serpentine fronts leaning inward in an effect related to that of Aalto's 'Northern Lights' wall in the New York World's Fair pavilion. The functional gain was that the distance to the stage for the spectators sitting highest up was the same as for those in the lowest balcony rows.
The side walls, which point towards the stage, are clad with a system of bent battens (originally to have been laminated wood, but because of the danger of fire eventually made of aluminium), which have both an acoustic and an aesthetic function. The ceiling, with a system of metal netting that is permeable by sound waves but hidden from sight, conceals an 'echo chamber' above with moveable acoustic screens producing the 'flexible acoustics' that Aalto had so long sought to implement in various ways. Behind the auditorium, and equal to it in height, is the foyer, with open, sinuous entrance galleries to the balconies forming an upward-growing light court - a mirror image to the auditorium.
As in the Helsinki House of Culture, Aalto mirrors the forms of these principal spaces in the exterior: the walls curve softly, and the whole massive structure is covered by a lean-to roof which takes a low step up above the auditorium and stage. The building stands alone, set in a park.
Delays and setbacks
The variation between successive plans was partly due to financial dictations and was alternatively enlarged and cut-back. Thus, a studio stage for 250 spectators was ultimately scrapped. Aalto planned to use white Carrara marble for the facades, but because of air pollution finally settled for dark cast aluminium.
Fortunately, however, before construction got under way, a granite that was light enough to produce the originally intended effect was found. Technical improvements also made the 'acoustically flexible' ceiling a success, which was not the case in the Finlandia Hall.
The final, purely aesthetic equilibrium of forms and proportions that was so important to Aalto's works, however, was partly lost in the 'hard', engineer-like implementation; thus, to some extent, the Essen Opera House lacks the aura of a genuine Aalto work.