subwoofer to speaker connection


I am a novice and would like to seek advice from fellow Audiogonians. In  reading the forum 128025-84361 (Jan this year) on speaker and sub connection, I am intrigued  by the comment   from rcprince “Virtually every review I have read remarks on how the mids and upper bass from the main speakers are improved when you add a subwoofer…”. I have a pair of Focus Audio Signature Series (Model 78) speaker and one Audio Physic Luna sub. Would connecting these 2 produce improvement in the sound of music? If so , how  can I  best connect my sub and speaker ? I don’t mind buying the high pass filter and inline cross over as mentioned in the above forum, if needed. Moses


moses189
Thanks both  bdp24 and stringreen for providing the "scientific" reason in having bi-amp. I will for sure buy the Hsu high pass filter and will be looking forward to detect the difference. 
On a sonewhat separate but related question I wonder if you can help to advice. There  is another Lectron amp JH50 tube (50watt) amp available from a store possibly selling for $1500. Would there be any major advantage in having 2 rather than just one such amp to drive the 2 speakers I have? (With one such amp,  I normally turn the pre-amp volume control to half way to produce adequate volume to listen in my small room, 12 ft wide, 13ft long, 8 ft high). Moses189
If you can use them as monoblocks, then yes, it would be an upgrade.
Possibly less so if you want to drive upper and lower frequencies separately.
One of the best things about monoblocks is that you can put the amps close to the speakers. Thus, using short speaker cables.
B

Thanks for your comments, gdnrbob.  I wonder if anyone would like to further comment on future upgrades of my system since spending $1500 for  another Lectron JH50 amp will not provide any tangible gain in the sound (to be used as monoblocks) after adding my sub+high pass filter, what would be the next upgrade that you would recommend: change  my  Audio focus (Signature series model 78) speaker, or Transcendent Grounded Grid Preamp, or  Linn sondek LP12  turntable with Karma cartridge?
Why not try out what you have and see if it makes a difference before you make your next move?
 I have tried the sound with and without  the Hsu bass optimizer.  I found that  combining my subwoofer with Hsu bass Optimizer with cross over at 60 Hz  to my amp,produced the music a fuller range.  The base part is especially better when listening to organ music  and a clearer voice when listening to Pavarotti singing. Any suggestion as to what would be a further worthwhile upgrade to explore with my system.