I added 2 SVS SB-4000 subwoofers to my M2 system and have a question about the crossover frequency. I have only been able to find one internet post about this and it said that when JBL adds the SUB18’s to the M2’s they are crossed at 175hz.

My processer has outputs for Stereo Subwoofers and can be configured for frequency and slope. I currently have a Synthesis SA4600 with the M2 files loaded powering the M2’s and my processor's crossover set at 170hz and 24db. The system sounds great but the 175hz seems rather high for a speaker that goes down to 20hz and was wondering if someone here could confirm the 175hz information or possibly have some other recommendations.