Hi Chris,
If you are using a WiFi Connection to the B2 then this connection is being provided by your House Router and this Router is responsible for the quality of the connection, the B2 is passive.
The B2 is a SERVER and needs a good connection to the Router (and from there on to the internet for some functions) and if it is not being provided with a good connection then it will/can not perform properly.
Your Phone and PC may seem to work OK on your home LAN but they are just going to the Router and out to the WAN/internet, the B2 is a service on your LAN/intranet and this an extra requirement on your Router.
When people have problems with the B2 they blame the B2 because that is what they perceive they are using, however many problems are in the "plumbing" (the LAN/Router), but this is invisible to most users. Just like real household plumbing,
you are in a mess if it not functioning properly.
You issue is probable a "plumbing" problem, for instance, since you first began using Spotify have you added anything electrical to your house (that could be causing noise) or has a neighbour got a new Router that is interfering with yours?
What is the strength and quality of the WiFi signal that the B2 is seeing (there are menu functions to tell you this).
Fred