At a minimum buy one of these:
Item # PW8R15AUD, 15 Amp, 8 Isolated Receptacle Point of Use Unit for Audio Use on Brick Wall
That'll help with the surge portion of the equation.
If you want to deal with the dips and surges you'll need something a bit more than just a surge/filter product. For that you'll want something more like a power conditioner. There is a fair amount of debate about what the various options do and don't do and while I hesitate to do anything other than give a direct recommendation in this case I can't. I use a MonsterPower product, which probably isn't the best but was reasonably priced and I've never felt like it was doing anything bad.