Do you think you need a subwoofer?

What does it sound like when running strictly a subwoofer or two below 80Hz?

And what should I listen for when adjusting phase?

I finally got a decent amp for my pair of passive subs, a Samson Servo 550 (275wpc). It's a pro/live amp used in clubs/bars/etc.

Anyway, I feed my subs via a Paradigm X-30 active subwoofer crossover with line-level inputs.

I am currently feeding the X-30 directly from my cd player's "fixed" outputs and my monoblock tube amps from it's "variable" outs while rebuilding my passive transformer volume control.

Anyway, last night while playing assorted jazz, classical, and rock I would intermittently turn the volume down on my main speakers to listen strictly to the subs output.

I expected to hear distinct, clear-cut, drum strikes or the clean resonance of standup bass strings, but that isn't what I got. Everything was rather muted in a undefined way. It certainly fleshed things out when mixed in with the mains speakers, but I expected more attack, I guess.

The best description would be a line that an audio reviewer once used - the subs recreate the trailing edge of a note rather than the leading edge. More resonsce and decay than strike.

I've tried varying the x-o frequency from ~60Hz-120Hz.

Does this seem right?

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Great thread guys; thanks for sharing the great information.
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Rgds,
Larry
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Dear Darkmoebius: What you are hearing is right: "Everything was rather muted in a undefined way. ".

For the low bass reproduction has " means " for our " ears " it has to be working with the midrange sound, other way ( 80Hz and down ) you will heard what you already heard.

Regards and enjoy the music.
Raul.

Thanks for clearing that up Raul, I was just a little worried that I somehow burned up my subwoofer crossover. Everything sounded great when both the subs and main speakers were playing, but when I turned down the mains, the subs sounded muted and out of focus.

Amazing what an influence such a bad sound can have. I thought instruments and voices sounded pretty damn good before, but now after hearing things with the subs, mains-only sounds thin and one dimensional.

The subs added depth and flesh to everything. Amazing because it does so with very little output. It really doesn't take very much volume wise. Although, what little it does, pushes my 275 wpc sub amp to it's limits on organ music and other sustained low frequencies.

Experiment. The bass may appear fragmented or incomplete but it works its auditory illusory magic with considerable authority. Put on a piece that has critcal bass, e.g. Yo Yo Ma Bach Sonatas. Ensure the bass and upper frequencies are balanced. Then measure the sound levels three ways: combined, bass only and without bass. You'll be surprised how high the dbs are for bass only. I use a separate modded BK 442 (200wpc) amp to drive a pair of separate passive sealed 10inch Hales bass drivers through an active crossover so its always adjustable. I turn the bass way down on poor bass recordings where the woofer just pumps, e.g. sadly RCA LP Heifetz/Reiner Tchaikovsky Violin Concerto; I couldn't do that with an internal three way fixed crossover. A modded BK M200 monoblock (200wpc) amps drive the mid/tweeters. I'm always surprised how much presence the bass driver creates and how hard the bass amp works. Through countless trials I now set the crossover at 120hz. A cello works the bass amp harder than the mid/tweeter amp. I can feel the difference in the heat sinks.