Headphone output volume.

Just tested again with an emu device which does trs subs.
The output is louder.
So how exactly can I connect ts to trs without a mixer.
I know it’s designed for mixer inserts but what’s the point in portability if I need to carry around a mixer as well.
Won’t it always attenuate If you connect a ts to trs even with special cable.
The cable you sell is just trs to trs I need ts to trs !!