subwoofer question

Sorry, Perrew.

To clarify:

The conceptual design goal of a highly damped subwoofer system is that, once the musical signal is stopped, the system will restrict the tendency of the driver to keep moving. The idea is that momentum is defeated and bass will be tighter (maybe "faster" to some) as the woofer quickly settles.

Hence my suspicion that some people equate big drivers (with lots of momentum) with slow bass. Some subwoofer tests include a measure ("group delay") of a sub's ability to accellerate, reproduce an input signal, and "settle" after the signal stops, but there is disagreement on the usefulness (and threshold audibility) of this spec. Highly damped systems typically show very low group delay relative to less highly damped systems.

Both the driver's inherent "springiness" and the box's ability to inhibit driver travel (this alone is a complex function of the box's size, shape, loading scheme, stiffness, etc.) contribute to the overall system damping. Therefore, there is no universal correlation between driver size, box size, and system damping. I don't want to overstate my technical expertise on the subject, so I'd suggest that you search a bit for technical info on "loudspeaker damping".

A little more bad news. IMHO, a subwoofer can be "overdamped" (too fast in my parlance) depending on the main speaker to which it's being mated. Again IMHO. Again, YMMV.

Good Luck

Marty

Bob is correct. My previous posts were my attempt to explain why there may be a common idea that a large driver mean larges inertia, means "slow" bass and why that idea may not hold water. I covered the momentum side. Bob closed the loop by explaining that the extra mass of a larger driver may be accellerated just as quickly as the lower mass of a smaller driver, provided that the force applied to it (the motor assembly) is also proportionately larger.

Bottom line: IMHO driver size and "speed" are not related. I am 100% sure that others will disagree.

Marty

Bob, Marty,

thanks for your answers!

We may be down to hair splitting now but if we take two similar subs like a JL Audio Fathom F113 and F112, these are very similar, do you guys still think the F113 ar faster?

Off my memmory of comparing these two at audition the sound quality was virtually indistinguishable to my ear. Both sounded very, very good (set up 2 channel with Maggies at a local hi-fi shop). I'm pretty confident that most listeners would find (provided that both are operated within their respective limits and without HT style effects info to distinguish performance below 20hz.) that they sound very much alike. The bigger sub will (presumably) play louder without distortion.

Marty