Hello Al7478
Gerrardasnails is correct.
From experience, I've found the best crossover frequency between the Q Acoustics 1010i and the 1000Si subwoofer is 85Hz - 90Hz. The crossover control on any subwoofer sets the upper limit to the frequencies (sounds) the subwoofer will emit. Therefore, in the case in question, signals lower than 85Hz will come from the subwoofer and signals above 85Hz will come from the 1010i speakers.
Best regards,
Steve Reichert -- PR Manager, Armour Home (Q Acoustics)