subwoofer to speaker connection

I like to thank both yogiboy and gdnrbob for sharing their experiences. I especially like to thank      gdnrbob for taking time in looking up the Audio Physic sub manual. Although my sub is an older version, with cross over settings 32, 46, 61,80,105 Hz , the overall capability is the same as that in the manual, except the new manual is lot more clear in the directions. My sub has both a volume and roomgain function to adjust the instrument sound. After reading the responses, I like to further seek input and clarification for further understanding

1.       gdnrbob mentioned that you “like using the high pass filter…but it means the sub and main speaker aren’t overlapping frequencies, and thus muddying the sound”. If I set 61Hz above to amp to run speaker and 80Hz below for the sub using the Hsu high pass filter, wouldn’t I have 61-80 Hz overlap? Would you suggest such overlap  or just 80Hz (or another frequency such as 61Hz)above to speaker and below to sub? By the way, your experience on improving the sound with connection to sub (like that express by rcprince that I first read in Jan 17 audiogon forum)  is what prompted me to explore this possibility since I have a decent sub not being used. (I did try to sell once last year at Audiogon, but no takers)

2.       Yogiboy you mentioned that you have tried many subs and always preferred your system without them. What kind of subs and speakers have your tried? May be your speaker is an excellent one and thus no need for sub.(The other day I listened to the demo of Magico speakers with Chord equipment in a store and found such fantastic sound from the set up which further prompted me to explore the improvement on my speaker since I have the spare sub) My speaker, Focus Audio, is an old one about 20 years ago that listed about US$4000 and the sub(Audio Physic)  about US$2000.  My pre-amp is Transcendent , and amp is Lectron HJ50.  I am looking to see if I can improve the sound from the speaker by connecting it with sub properly,  so I can  truly test if there an improvement.

By the way, I am very thankful to the Forum and Audiogonians in sharing and advising inexperienced individuals like me. Really appreciate the help. Moses189

The reason "the mids and upper bass from the main speakers are improved when you add a subwoofer" is because relieving the main speakers of reproducing very low bass (assuming you are highpass-filtering the signal sent to those speakers and their power amp) can greatly reduce the distortion they are producing. The lower the frequency a speaker is trying to reproduce, the harder it has to work (move air), and the more distortion is creates, generally speaking. If the woofer isn’t having to produce low bass, it can produce upper bass and mids freer of distortion.

That’s why many Maggie owners use subs with their speakers---not just to provide the very low bass that Maggies don’t, but to reduce the amount of upper bass and midrange distortion that results from relieving the panels’ magnetic-planar bass driver of moving far enough to reproduce frequencies below 40Hz or so. The same is true of many other speakers as well.

If one doesn’t highpass the signal going to the main speakers and their power amp, that advantage of bi-amping is lost.