It all begins with a sound-recording environment. My booth has been quality-controlled by https://georgethe.tech/

The noise floor (Normalized to 0dB) is -56dB, which provides a very clean sound. Applying a high-pass filter allows it to drop down to -65dB.

The room had a standing wave resonance (A "room mode") at about 70hz-80hz, which was resolved with a large bass trap from https://www.atsacoustics.com/

NEUMANN MT48 - UNIVERSAL AUDIO APOLLO TWIN X QUAD - MOTU M4 - RODECASTER PRO II - SOUND DEVICES MIXPRE 6 & 10 - ART VOICE CHANNEL PREAMP

SENNHEISER HD650 - BEYER DYNAMIC DT990 PRO 250, 770 PRO 80 & 250 OHM - STEVEN SLATE VSX - DROP ETYMOTIC ERX - LITTLE LABS MONOTOR - ADAM AUDIO A4V - YAMAHA HS5 & HS8 SUBWOOFER