Dear Sirspeedy and Rauliruegas,
On this subject, I would like to offer my opinion.
First of all, this thread has become a grenade tossing exercise, and from two people whose words in these rooms I greatly respect. Pardon me in advance if I don't have a great knowledge of intermodulation distortion and harmonic distortion, however, I do have a good set of ears being a life-long non-professional musician and a professional editor who mixes his own audio for air on a major TV network. I am your common "joe". And I am like 80 percent of us here: what I don't know in engineering and theory I make up for in listening with my head and my heart.
I have a great 2 channel system....Krell amp, Adcom GFP 750 pre-amp flowing into a pair of Dunlavy SC3's. They are great speakers: very revealing, time and phase coherant, and have a very small sweet spot. They have plenty of slam, but are rated at only around 40HZ at the low end (the top? forget about it, just glorious). Anyway, I wanted to round out the low end an extra 10 or 15 hertz. So, I bought a Von Schweikert VS-1 subwoofer, and stuck it just left of center. Now I hear this wonderful bass presence, increased slam, and an overall heft that is not too overbearing, but just enough to make me smile. I set the crossover on my sub at around 40K to let my Dunlavy's handle everything that they do best and let my sub do the rest. One sub, an extra 15 hz in the low end, and I am happy as a clam.
Sirspeedy, your explanations and experiences are very well written and understandable. Thanks for your info.
Raul, your knowledge of this hobby is at a level way above me, but I sure respect and appreciate it, always have, always will.
Just a "common Joe" here, throwing in my 2 cents.
Raise the faders on the pre-amp, it's another sunny day inside!! Cheers!