Velodyne used to a make a model SMS-1 which would measure the room resonances via microphone and adjust the bass response accordingly. All is adjustable with the crossover itself to merit individual taste or components.
Another alternative is a passive set of devices such as those made by Harrison Labs. In this case, you are on your own choosing frequency, but not slope. Though these products don't seem to be so high end, they contribute little to the twisting of frequencies as do the more 'modern' digital products that I have used.