Problem with inductor Pleiades filters

There is distortion of mid lows when directional mics are used at close distance.


Possible cause: Overloading of the magnetic core due to the excessive and unnatural mid bass emphasis of the proximity effect.


Possible remedies:


Using omnidirectional mics. They sound amazing just the way they are. The simple inductor in parallel Pleiades filters will adequately reduce any remaining bass heaviness due to Fletcher Manson equal loudness curves or voice effort curves (singing softly produces much LF and HF).


Using directional mics with a higher membrane reasonant frequency used to compensate for the proximity effect. There are examples of such vintage mics by Electro-Voice, Sennheiser, Beyer etc.


Using very large magnetic core for parallel (shunt) filters or input, output transformers. Is this a reason why the signal transformers in the RCA microphone booster amplifier BA-2C are so large?


Using a resistor (variable if wanted) in series with the inductor. Then the resultant in parallel with the mic output. Is this what is used on MD421, MD441? A schematic can be seen on the AKG D1000 mic.


Using a coupling capacitor instead of an in parallel (shunt) inductor. See next euroelectron post.



Reference:
Flat frequency response from singer's vocal chords to listener's brain, Sound Picture Recording and Reproducing Characteristics - Loye, Morgan - JMPSE