Speaker sensitivity

polkfan38
polkfan38 Posts: 360
edited December 2010 in Speakers
What factors determine a speakers sensitivity?
Things are more like they are now than they ever will be!
Post edited by polkfan38 on
· Share on FacebookShare on Twitter

Comments

  • cristo
    cristo Posts: 231
    edited December 2010
    Lots of things:
    enclosure design (folded horn more efficient than vented or passive radiator more efficient than sealed box),
    voice coil structure, magnet structure, size, weight/density of driven material (cone, dome, electrostatic panel, etc.),
    stiffness of surrounds, crossover design, . . . I'm sure there's more, but that's what I can think of just off the
    top of my head.
    Sensitivity is typically measured in db of spl (sound pressure level) averaged over a frequency range and measured
    at 1 meter distance from the speaker when driven by 1 watt of signal (db/W at 1m).
    It's sometimes specified as db at a particular input voltage, then you may need to know the impedance
    to convert to db/W so you're comparing apples to apples.
    2.83 volts (actually 2.8284....) with 8 ohm impedance is 1 watt (P = V²/R in this case)

    The higher the efficiency of the speaker, the louder it will be when driven by a given amount of power.
    cristo

    NAD C 545BEE cd player, Philips AF877 turntable / Shure V15V-MR with JICO SAS stylus,
    Tascam 122 mkIII cassette deck, Harman Kardon 3480 receiver, Terk FM-50 antenna in the attic,
    Soundcraftsmen SE550 stereo equalizer, Polk Monitor 10a speakers
    (with Sonicraft/Solen/Mills crossover rebuild)
    · Share on FacebookShare on Twitter
  • polkfan38
    polkfan38 Posts: 360
    edited December 2010
    The only flaw I see in your post is that "vented more sensitive than a sealed box" I have owned and seen many sealed designs with ratings over 100 dB. But I am sure the other components came into play here.
    Things are more like they are now than they ever will be!
    · Share on FacebookShare on Twitter
  • cristo
    cristo Posts: 231
    edited December 2010
    Yes, these are generalizations. Also, I guess I meant "acoustic suspension" instead of
    sealed box, as a passive radiator design (like our beloved Polks) is technically a sealed box
    but it acts more like a vented or reflex design.
    cristo

    NAD C 545BEE cd player, Philips AF877 turntable / Shure V15V-MR with JICO SAS stylus,
    Tascam 122 mkIII cassette deck, Harman Kardon 3480 receiver, Terk FM-50 antenna in the attic,
    Soundcraftsmen SE550 stereo equalizer, Polk Monitor 10a speakers
    (with Sonicraft/Solen/Mills crossover rebuild)
    · Share on FacebookShare on Twitter
  • TNRabbit
    TNRabbit Posts: 2,168
    edited December 2010
    The type & quality of materials used in the crossover can also affect the sensitivity.
    TNRabbit
    NO Polk Audio Equipment :eek:
    Sunfire TG-IV
    Ashly 1001 Active Crossover
    Rane PEQ-15 Parametric Equalizers x 2
    Sunfire Cinema Grand Signature Seven
    Carver AL-III Speakers
    Klipsch RT-12d Subwoofer
    · Share on FacebookShare on Twitter
  • polkfan38
    polkfan38 Posts: 360
    edited December 2010
    What gets me is that you see some high end stuff with sensitivity ratings in the low 80s. Wouldn't they strive to get it a little higher? For those prices?
    Things are more like they are now than they ever will be!
    · Share on FacebookShare on Twitter
  • TNRabbit
    TNRabbit Posts: 2,168
    edited December 2010
    polkfan38 wrote: »
    What gets me is that you see some high end stuff with sensitivity ratings in the low 80s. Wouldn't they strive to get it a little higher? For those prices?

    It's a balancing act between all the elements. Some of the best sounding speakers in the world are a hard load for many amplifiers (Klipsch Jubilee excepted!). My guess is to get that extra something requires dipping down in the efficiency. I think Apogee Scintillas are @ 80dB (!) efficient & dip to 1 ohm impedance at certain frequencies, but are considered by many to present one of the finest sounds on the planet.
    TNRabbit
    NO Polk Audio Equipment :eek:
    Sunfire TG-IV
    Ashly 1001 Active Crossover
    Rane PEQ-15 Parametric Equalizers x 2
    Sunfire Cinema Grand Signature Seven
    Carver AL-III Speakers
    Klipsch RT-12d Subwoofer
    · Share on FacebookShare on Twitter
  • cristo
    cristo Posts: 231
    edited December 2010
    As far as type & quality of crossover materials, as long as you're keeping the same values,
    different brands of resistors and capacitors should not affect sensitivity. Inductors can vary
    regarding resistance for a given inductance value depending on wire gauge and construction, and this can affect sensitivity slightly.
    cristo

    NAD C 545BEE cd player, Philips AF877 turntable / Shure V15V-MR with JICO SAS stylus,
    Tascam 122 mkIII cassette deck, Harman Kardon 3480 receiver, Terk FM-50 antenna in the attic,
    Soundcraftsmen SE550 stereo equalizer, Polk Monitor 10a speakers
    (with Sonicraft/Solen/Mills crossover rebuild)
    · Share on FacebookShare on Twitter