Understanding speakers Specs

Discussion in 'Home Theater Lounge' started by geppy_41, May 13, 2007.

  1. geppy_41

    geppy_41 New Member

    I need to find a place where I can find out about speaker specs such as the "Q" of a speaker and what it means. Along with all the other specs. I really don't need to know the techinal jargan but what it does to the sound and how it relates to everything.


  2. DYohn

    DYohn Well-Known Member Donor

    Hmm. I'm afraid there is no such thing as understanding concepts like loudspeaker Q without getting into the "technical jargon." However, I can offer a good place to start, so maybe you can get a handle on the jargon.

    TRY THIS resource, courtesy of Eminence.
  3. cjd

    cjd New Member

    It's not that simple, even when it is. ;)

  4. Michael P

    Michael P New Member

    Hi Jeff,

    Like David said, the easiest way to understand what it does to the sound is to take in the technical jargon... slowly. :) There aren't many places to learn what these things mean without knowing anything in advance. I'll look.

    The term 'Q' (quality factor) can be used to describe many different things... resonant circuits, inductors, speaker drivers, sealed speaker systems, etc. It is basically a ratio of stored to dissipated energy, so "higher Q" means "less damping." If you look at a frequency response graph containing a peak or knee in it, Q corresponds to the sharpness. (There is some math here; I'd be happy to write some of it down for you.) For a highpass response like that of a subwoofer, the Q determines the shape of the frequency response curve around the lower corner frequency. Higher-Q systems have a response that cuts off relatively sharply, perhaps peaking before that. Lower-Q systems "roll off" more gently.

    I can't tell what particular thing you are interested in the Q of. Sometimes the particular "kind" of Q is specified by subscripts. Drivers have mechanical (Qms), electrical (Qes) and overall (Qts) factors. For sealed woofers, the system can be described by the Qtc value (which must be higher than Qts). For any given driver, larger boxes have lower Qtc, more low bass and less punch.

    There isn't much agreement on what the "best sounding" Qtc is, but 0.5 and 0.707 are popular. A system with a Q=0.5 settles down quickly if you excite it with an impulse. A system with Q=0.707 has the flattest anechoic frequency response.

    Does this help at all, or at least get you thinking?

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