Pay attention to polarised sources like drums and vocals.
Vocals sound like someone speaking towards you, or their back facing you according to polarity.
You need flat phase characteristic speakers to hear it properly.
Warning - Once you understand and can hear the difference you can't go back.
I think he's just asking if the Z4 has an inverted output. It does as far as I can tell. The buffer as implemented is not inverting, and the gain stage still is. so BOZ+ZV4 should = correct phasing. I also modelled the circuit just to double check.
I also prefer to listen to the records as they are recorded.
Yes, I made a big mistake while I wrote the post.
BOZ invert phase and Zen V4 also invert phase. The input buffer does not invert, but output stage invert. So the absolute phase is correct. The Zen V4 shematic show the output on output capacitor as - and GND as +. Is this becouse ZEN invert phase ? (my opinion is that this is this). So combination ZEN V4 and BOZ does not invert the absolute phase, so output on output capacitor is + and GND is - to speaker.