In a room that size, you can get away with -3dB at 40Hz pretty easily - especially with some furniture and doorways in the room. There are many floorstanding options with this level of bass output. Your room is close to mine (14x13) and my speakers are 38Hz at -3dB but I have some bass traps in the corners and speaker placement was fairly critical. So anything with a little less bass than that should be fine for your situation.
Most monitors won't have this kind of extension so if you can live with less bass, then they are a fine alternative. I personally feel that solid bass extension is required for high fidelity, but to each his own.
Arthur
Most monitors won't have this kind of extension so if you can live with less bass, then they are a fine alternative. I personally feel that solid bass extension is required for high fidelity, but to each his own.
Arthur