Woofing "Q"

My Rythmik subs have variable Q. Seamless integration (to my ear) was often possible at more than one "Q" setting. Sometimes, my preferred Q setting changed, depended on other x-over variables (like slope and and x-over frequency). And, even though seamless integration was possible at different Q settings, the overall character of the system definitely changed, depending on which combo of Q and other parameters was chosen.

Generally speaking, I found that it is definitely possible to "mismatch" the Q of the sub and main speaker (when it's wrong, you'll know it), but there is no one perfectly "right" answer. I suspect that some degree of experimentation is probably useful to optimize Q to personal preference. I would personally recommend a sub with variable Q for this reason.

Marty

I'm not sure I have a great answer for that. Slightly underdamping the sub can make the system feel a bit more dynamic and punchy, slight overdamping it can make it seem more transparent. Too much damping and things can go dry and lifeless. However, for me, extreme underdamping is probably the worst condition so, twist my arm, and I'll say that underdamping the sub is worse.

Shadorne's comment re: "sealed subs only" is probably, as a practical matter, good advice for a music only system, but it may be a bit of an overstatement. The SVS subs he mentions shouldn't be dismissed. Their top model, in it's fully ported configuration, outperforms most sealed boxes on group delay tests. This test usually favors sealed, highly damped designs - but the SVS Ultra shows awfully well. Also, like all ported subs, it offers more deep, clean output capability than a typical sealed box design of similar size and amp power.

That latter item may not be critical for most music (how much musical program material has deep bass info <30hz, anyway?), but it begs a question:

How do you intend to install the subs?

If you're going to roll off the bass to your mains and cross at or above 60ish hz, I'd say sealed boxes are safer bets. If you're gonna run the main speakers full range and "snug up" a sub below their natural roll-off, then it becomes a more open question. Many users on this forum run their subs in this fashion, often rolling off their sub's upper response somewhere below 50hz. In this configuration, a ported box (particularly a good one like the SVS seems to be) may make more sense.

Good Luck

Marty

Shadorne,

Funny, I was thinking the same thing! You and I are the only two posters I can think of who always qualify their statements in a thoughtful and appropriate manner. Yay us!

Marty

Lewhite,

I'm pretty sure that trial and error is the only way to be sure that Q is adequately matched. That why I like variable Q subs, whether the Rythmik system, or SVS' open/blocked porting system. Either should allow you enough flexibility to find a good match with most main speakers. Also, both brands are sold direct with a money back in-home trial period. BTW, there may well be other brands out there with this feature, too - so I'm not suggesting that these are your only options. I will note that both appear to be highly regarded and that I'm personally very happy with my Rythmiks.

Good Luck

Marty