Hi Keith
You asked for views and I have two thoughts, based on what you've said.
Firstly, while the B2 has the capacity to act as a stand-alone music system (just add speakers) you can't expect too much of it regarding playback. It offers high quality, lossless CD ripping, cataloguing and storage, user-friendly internet radio, direct streaming with Spotify Connect and an innovative YouTube music feature. One of the benefits of ownership is that new functions are added to that list from time to time, such as Sonos connectivity, at no extra cost. But playback quality options are inevitably compromised, not least by the size of the B2 box and what can, therefore, realistically fit inside it. However, attach an optical cable to it and connect the other end to an external DAC and amp and those options are greatly expanded. It will play back CD quality files as well as a high end CD player.
Secondly, I've looked closely at the B2's graphic equaliser and can't find any problem with it; in fact I was surprised how well it works. But it does what any equaliser does when it sits within a signal chain. That is, if you're not careful, it can add gain as well as tweaking the "tone". And adding gain can cause distortion. It sounds as though you are trying to use the equaliser as a tone control: if so, that will only drive you crazy. The best way to think of an equaliser in a hifi system is as a way to compensate for the acoustics in the room or, just maybe, some generic deficiencies in the rest of the system (speakers with consistently harsh treble for example). If you can find a single setting that makes everything sound a little bit better, set it and leave it like that. If you can't find that setting, the problem probably lies elsewhere.