Harman’s calibration target curve encoded deliberately tilted in-room response, not flat room response

Evidence

There have been multiple “Harman curves” over the years. They have been named by others, not by Harman, and their meaning and use have been routinely misconstrued. Going back many years, JBL Synthesis systems, upmarket home theater packages, included a “calibration” service to finalize the installation. This was done using in-room measurements, room curves, and there was a target curve that had a slight bass boost, because that was what sounded right to most customers for movies at their chosen playback levels—usually below calibrated cinema level. This was followed by a smooth, almost straight downward tilted curve. Most EQ adjustments were done at bass frequencies to address room resonances. How did we know that this room curve was the right target? Because Harman designed, manufactured and measured the loudspeakers. It was known that if this curve was measured in situ, the loudspeakers were working properly and the listeners would be receiving an essentially flat direct sound, the one that is primarily responsible for perceived sound quality. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1340

Categorization

• DEFINE: Clarifies what the ‘Harman curve’ actually was: a tilted in-room target derived from knowing the anechoic loudspeaker response, meant to ensure a flat direct sound rather than a flat room curve.
• XREF: Connects to Olson/Toole’s evolving debate about flat in-room vs. tilted targets, and to the reader’s broader psychoacoustics interest in how perceived sound quality maps to measured response.