Alcira Philharmonic Hall

The hall had been converted to LED four years earlier by a contractor working from a like-for-like schedule, and the result was a disaster in exactly two ways. The house fade now stepped visibly in the last five percent, so the room went from dim to black in a jump the audience could see; and the drivers flickered at 1.2 kHz, which the national broadcaster picked up as banding on every slow camera pan. Neither fault was visible on a datasheet.

We rebuilt the dimming from the bottom. Every driver in the auditorium is now amplitude-dimmed with a measured percentage flicker below one per cent at all levels and a stroboscopic visibility measure under 0.4, verified on site with a flicker meter and a broadcast camera, not taken on trust. The house curve is a custom square-law with a 0.1 percent floor and a twelve second fade, which is slower than any preset and matches what the orchestra had been used to under tungsten.

Mass was the other constraint. The acousticians would not accept added weight or new penetrations in the coffered ceiling, so the 96 downlights sit in the existing apertures on the original back-boxes, with a machined adaptor plate that keeps the total within eleven grams of the tungsten fitting it replaced. Stage lighting, house lighting and the foyer are on separate protocols but one master timeline, so a single front-of-house cue takes the whole building from interval to performance.