Most music is mixed not to have any useful spectral information below that frequency anyway. And if you want beat then a better thing you can do is look at the

Most music is mixed not to have any useful spectral information below that frequency anyway. And if you want beat then a better thing you can do is look at the half-wave rectified difference between the sums of two FFT frames (with optional lowpass). This results in an onset graph that is the basis for a lot of real-time beat detection algorithms.