Its lower -3db point is 61hz, so it's best that you don't drop below 80hz for a crossover.
There are a number of factors you need to look at:
There are a number of factors you need to look at:
- Capability of the speakers. We've looked at the bookshelf, but what about the center?
- Capability of the sub. If it had poor performance above 80hz, that might lead one to a lower crossover.
- Room response. If there are some problem frequencies between 80 and 120hz (big dips or peaks in response due to room modes), then sending those frequencies to the sub allows you to place the sub where those frequencies are not wildly varying at your listening position. This is the tricky part, easiest if you have test tones and a sound level meter, or free measurement software.