If you are using a site like youtube on repeat the music will auto-lower when you are being summoned or someone is invading.

white soapstone .

always changes color... ive never been surprise invaded once

Fuxtard, voice chat does work in PvP, but only if you're wearing the Ring of Whispers.

you can also open youtube videos on the steam browser, it allways worked for me too

It's actually a windows setting that makes this happen and it happens because dark souls 2 has in game voice capability, however it doesnt work for invaders so i dont know why the volume is even effected, and its pretty annoying.

how to stop it happening cuz its annoying when you are listening to music and either pve or pvp'ing?

Control Panel > Hardware and sound > Sound > Communications (Tab) > Select Do nothing.
Apply > Ok.

How to tell if you are being invaded if you use this fix? try sitting at a bonfire, try using a soapstone. if you cant do either you are being invaded, alt-f4 quick :)

This works great, friends and I do this all the time.

If you've placed soapstone on the ground then it will also disappear before an invasion.

Also, some stuff I use is:

Soapstones are grayed-over
You can't used over
(Easiest/Most Reliable) your internet will skip just a bit when you connect to someone.

The screen also freezes for a second, at least in my case. That's how I usually know, kinda hard to notice sometimes though.

i do alot of lunar bell red or grey invading /being invaded so it works there atleast