Paul McGowan writes:
It isn’t clear that we even want our loudspeakers to be flat and perfect. There’s reasonable evidence that we don’t.
My former partner in Genesis Loudspeakers, Arnie Nudell, was famous amongst insiders for what became known as the “Nudell Dip” a carefully crafted reduction of volume in the critical 500Hz to 2kHz region. This small dip in amplitude helped Infinity and Genesis loudspeakers have depth and the ability to disappear in the room.
When I first learned he did this I was horrified that anyone would do anything but make it flat. Arnie told me “loudspeakers will always be anything but flat, so why not take advantage of that fact and tailor the sound to your advantage?” He was right. The flatter we made the speakers the worse they sounded.
Recording and mastering engineers use less than perfect speakers to create the sound on our recordings in the first place. Perhaps if they used a mythical flat loudspeaker to do their work in the first place the Nudell Dip wouldn’t be a good thing. But they don’t.
Imperfection at the source breeds imperfection at the output for best results.
Your mileage may vary.