Not enough info, as others have said.
Regarding "fast", there is no such thing as "fast" 60hz, or 50hz, or 40hz, etc. They all travel at the speed of sound and have periods (the time for one wavelength) equalling the reciprocal of the frequency.
Many "perceive" speed or lack thereof based on distortion. High second order distortion at lower frequencies is the bane of many loudspeakers and subwoofers. Adjustability is a real plus in a crossover. The key is getting a low distortion subwoofer with a crossover that is steep enough for your main speakers to not have a bump in the upper bass where they overlap, which will also cause you, I think, to say the bass is "slow".
Regarding "fast", there is no such thing as "fast" 60hz, or 50hz, or 40hz, etc. They all travel at the speed of sound and have periods (the time for one wavelength) equalling the reciprocal of the frequency.
Many "perceive" speed or lack thereof based on distortion. High second order distortion at lower frequencies is the bane of many loudspeakers and subwoofers. Adjustability is a real plus in a crossover. The key is getting a low distortion subwoofer with a crossover that is steep enough for your main speakers to not have a bump in the upper bass where they overlap, which will also cause you, I think, to say the bass is "slow".