Re: Stereo subs - Do they rock or is it overkill?
Unless you are fortunate enough to own truly full range speakers you should acquire a quality sub as you are missing a great deal of foundational music information if you do not. I have owned several subs and have settled on the Sunfire Junior MkII as the one for my 15 x 20 living room. Sub(s) take some care and precision to integrate perfectly into the sound field and response of your main speakers but are indispensable if your music runs the gamut down to the final audible octave of 20Hz -- and a surprising amount of orchestral, electronic, new age and rock does have information in that range.
There is also a guttural impact to these bass notes that is missed entirely or distorted by even some so-called full range speakers that may grouse and grumble mightily trying to achieve those notes -- and may do so -- but in their efforts can over-power the room with bass the next ocatve or two upwards giving boominess we all have heard too often at Visions etc.
There is no better cost-effective measure to audibly improve your sound system that to insert a sub. Equal money spent on amps, preamps and sources -- let alone snake-oil high cost cables and cords -- will not improve your sound one iota in comparison. These things may make your system sound different but not better. The sub will make it better. So If your source is capable of grabbing 20Hz and feeding it into your system, you owe it to yourself to hear it and the sophisticated textures it will bring to your collection of music.