Welcome back to the forum!
Let’s finetune this a bit. You “have to” (too strong a phrase) hear your field enough so that you can tell if/when it stops playing. For a lot of us, that level of volume can be the lowest possible setting on our devices, just like was said in that part of the FAQ you quoted.
Are you meaning over-the-ear headphones which would block out your sapien audio? That’s less than ideal because your headphones would be blocking the field from your ears and, therefore, your mind. Sure, your external energy systems are taking in the field (and that’s good) but our mind is also part of our energy systems. I’d think you’d want all of your energy systems to benefit from your fields. Or am I missing something?
There are many ways I can interpret these words. And I know you’re wanting clarity, so let me see if I can help you here with that.
It’s not a good idea to listen to music and fields on the same device, because most devices are designed to process only 1 audio stream at a time. When you listen to both music and fields on the same device, the standard device processes the two together, which messes up the field. So, if you’re going to do this, play your music on one device and your field audio on a different device.
The same processing thing goes on with earphones. For example, I have some earphones (earbuds and headphones, to be precise) that will play audio from two different devices at the same time. (When that happens, it confuses me, but they can do that.) In this instance, these earphones would be messing up my field.
I’m, wondering if I got there for you, because I’m not sure what you’re reaching for (since you had already found what I would think is your answer in the FAQ). Feel free to ask more questions until we get you the clarity you’re wanting.