My Quad subs have specs that say -6 DB @ 25HZ. I set the Tact menu at 30HZ for measurements. My subs have several built in crossover selection points. I selected 55HZ because I measured my main speakers by themselves, saw them peak at 80HZ (at about +4DB) and then start to fade out.
(Send me an email and I can send you a picture of the graph)
The Subs have an 18DB HF roll off so crossing at 55HZ allows for the composite of the two speakers to be roughly flat, with the Tact only smoothing the result. The less correction the better.
My subs are as close to my main speakers as physically possible. Obviously trial and error can refine the results. I found that the lower the crossover point the better- provided no "hole" resulted. I also found that the even though the main speakers still contributed down to cut off at 30HZ, that the few DB of reduced volume made all the difference. Your results may vary.
(Send me an email and I can send you a picture of the graph)
The Subs have an 18DB HF roll off so crossing at 55HZ allows for the composite of the two speakers to be roughly flat, with the Tact only smoothing the result. The less correction the better.
My subs are as close to my main speakers as physically possible. Obviously trial and error can refine the results. I found that the lower the crossover point the better- provided no "hole" resulted. I also found that the even though the main speakers still contributed down to cut off at 30HZ, that the few DB of reduced volume made all the difference. Your results may vary.