An opera house is a shorter room than a concert hall and it is short on purpose. Fenmore holds 1,850 people in 12,240 m³ — 6.6 m³ a seat, two-thirds of what we would give a symphonic room — and the reason is that a singer has to be understood over an orchestra that is louder than they are. Every cubic metre you add lengthens the decay, and a long decay is the enemy of a consonant. The brief said 1.5 s occupied. We designed to 1.55 s computed and were content to be a little over, because a room measured empty and modelled full always has a margin of error and it is better to spend it on warmth than on dryness.
The horseshoe is not nostalgia. Tiered boxes put a large fraction of the audience close to the stage and, more usefully, they cover the side walls in deeply modelled surfaces at exactly the height where a plain wall would return a single strong late reflection. Box fronts scatter. The 1,200 m² of timber panelling on battens behind and above them is the other half of the argument: it is a panel absorber, it works low, and it is the reason the 125 Hz figure lands at 1.82 s rather than the two and a half seconds a plastered room of this volume would give.
Two hundred and sixty square metres of heavy velour, gathered to half its flat area, hangs in the stage house and the upper side slips. Draperies are the only element in an opera house that can be adjusted after opening night without a scaffold, and we specified more of them than the model needed so that the music director would have somewhere to go. Three years on, about a third of it is tied back. That is what it was for.
The pit is where we did not get our way. We asked for a pit rail that could be raised and lowered by 400 mm to trade orchestral balance against sightlines, and we asked for the pit floor to be timber on joists rather than the screed that was drawn. The rail was built fixed, at the height the director of the day preferred; the floor was screeded. The consequence is a pit that is a little bright for Wagner and exactly right for Mozart, and a house that will have this argument again in twenty years when the rail is next touched. We recorded the position, the measurement and the reason in the handover report, so that whoever has it has something to start from.