Why "identity" simulation filters in Reference are not flat?


Hi there,

I've started exploring the Reference 4 plugin, and have stumbled upon the fact that if I choose "AKG K712" as "Calibration profile", and then choose "Studio headphones with Austrian heritage" as the simulation preset, or in the same way choose "Sennheiser HD650" as the source, and "German studio headphone" for the simulation, the resulting correction curves are not flat.

I'm assuming that "Studio headphones with Austrian heritage [...] The series number [...] 712" is AKG K712, and similarly, "German studio headphone [...] model nr.650" is HD650. Thus, no correction should be needed.

So obviously, the source and target profiles for these headphones are not the same. Is that intentional, or am I dealing with some inconsistency in your package?

Attaching pictures for your convenience.


Permanently deleted user
Official comment


So, I'll explain this in steps:

  1. When you select an average profile, it takes the updated average profile (our most popular profiles have been updated down the road) and applies the flipped profile curve to the audio source so that it's as close to "flat" target as possible, by using average profile.
  2. When selecting a target from either Simulate or Custom curve, the software tries to adjust the previously achieved "flat" curve to sound like the selected target.
  3. But because of what I mentioned in the point #1, we've updated some of our average profiles, but not the Simulate targets. This is what's causing the correction to be "curvy". You can see in the graph that whenever simulate target and the profile EQ curve matches, the correction is at 0.


Hope this clears this up a bit :)


Yes, that makes sense. Thank you very much for the explanation, Matīss!

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