One of the most damaging misconceptions about DSP quality is evaluating it primarily through target-tracking performance. This notion has unfortunately been heavily promoted as a marketing tactic by mediocre automated DSP tools for decades, since it's easy for users to verify and easy to "optimize" with filters. Consequently, many people who believe they are making a technical assessment of DSP end up falling into this trap.
In reality, nothing harms good sound more than aggressively boosting dips merely to force a flat target curve. It's often wiser to accept certain response dips as unavoidable limitations of the room or speaker placement (frequently they aren't even audible) and focus instead on what can genuinely be improved above that baseline.
As
@umamiaudio and
@Keith_W notes, even careful boosting of minimum phase dips can reduce maximum SPL, while any broader boosting degrades overall sound quality. Yet people still treat "how well dips are filled under the target" as the primary metric for judging a calibration, which is deeply misleading.
An even worse habit is extending target tracking to higher frequencies above the room's transition zone. This has also been falsely marketed for decades for the very same reasons. It's easy to demonstrate and easy to sell and has become deeply ingrained in consumer thinking.
There is some merit in using crossover design to avoid problematic dip regions, though it remains an imperfect solution. Similarly, systems employing additional support speakers with MIMO filtering have significantly improved the situation. However, traditional SISO approaches remain constrained by these misconceptions and will likely continue to suffer from them since it's easier to believe than to understand and the majority will automatically opt out of the latter.
