Hello,
It's clearly advisable to use a mixer for this, if only to adjust the levels for example. If all the sources that 'end up' on this hub are of the same type (e.g. line level) this may work but, once again, different levels will make the task very difficult, not forgetting the problems of mass which can cause 'hum' on the line. As far as I'm concerned, it's a headphone multiplier that works very well in this configuration and I'm very happy with it.

It's as described: from one audio source to 5 headphone outputs. For something like this, you need a mixer.