If you want not only deep base but 'articulate' base, get a PS Audio DL3 with a Cullen Circuits mod. It not only resolves lower frequencies better than the stock, it also opens the air around the bottom end better. You'll hear the wood of the kick drum instead of a dull thud. You'll hear the resonance of the strings on the base instead of a simple low pitch rumble.
It runs you about $1,500 new. While it is more than you want to spend, you won't find equivalent bottom end performance for under $2,000.
It runs you about $1,500 new. While it is more than you want to spend, you won't find equivalent bottom end performance for under $2,000.