Concorde was only louder than the rest on takeoff and initial climb out - because the reheat was on. Reheat is stupidly loud. Reheat was needed as it was optimised for super cruise (sustained supersonic) - something even fighters aren't, which made it very inefficient at takeoff speeds.

On approach and cruise it wasn't that much different from other jets of the era.

Modern engines could be far quieter and not need reheat for takeoff.