If Mac were here, he might say at this point to make the volume level on the headphone output as loud as you can without distortion, then set subsequent levels. What you are trying to do is approximate the output level of a LINE OUT jack that you don't have. It is very easy with headphones to put out more than that.

I like Notes' point to try to avoid that headphone jack because it has a habit of breaking and, as he said, will crackle terribly if jostled. A real audience killing sound. So, I suggest you get a small USB to audio interface. I've seen these from Griffin for about $30. They give you a noise-free headphone jack that supplies the line-level signal you are really needing here.

Even something as inexpensive as this would be better than using the laptop's headphone jack: http://www.newegg.com/Product/Product.aspx?Item=N82E16812186035


BIAB 2024 Win Audiophile. Software: Studio One 6.5 Pro, Swam horns, Acoustica-7, Notion 6; Win 11 Home. Hardware: Intel i9, 32 Gb; Roland Integra-7, Presonus Studio 192, Presonus Faderport 8, Royer 121, Adam Sub8 & Neumann 120 monitors