You should just sell me your B2000. I'll give you a good price for a defective unit that has substandard equalization for your needs.
Some will say that speakers do not need to be broken in. I run a few CD's through mine at ever-increasing volumes just to exercise them a bit. But then I'll just play through them and they will naturally warm up over time.
Without knowing your bass and how the B2000 is set, it's impossible to say why your A string isn't punchy.