I also own the Presonus HP4 Headphone amp. It has plenty of volume. The way mine is setup is I took the main outputs from my Presonus Audiobox and went to the inputs of the HP4. Then I sent the outputs of the HP4 to my M-Audio BX5a powered monitors. I am also using a dbx 286s mic pre-amp before the AudioBox. This setup works for me.


BIAB 2024 Ultrapack- Studio One Pro 6.5 Windows 10